Acquired Apraxia of Speech

The scope of this page is limited to acquired and progressive apraxia of speech. See ASHA’s Practice Portal page on Childhood Apraxia of Speech (CAS) for information about speech motor programming disorders in children. CAS can, however, persist to adulthood, and special considerations should be made for adults with previously or newly diagnosed CAS seeking services due to impact on functional communications. See the Apraxia of Speech (Adults) Evidence Map for summaries of the available research on this topic.

Apraxia of speech (AOS) is a “neurologic speech disorder that reflects an impaired capacity to plan or program sensorimotor commands necessary for directing movements that result in phonetically and prosodically normal speech” (Duffy, 2013, p. 4). AOS has also been referred to in the clinical literature as verbal apraxia or dyspraxia. For the purpose of this page, AOS will refer to acquired AOS; most information, especially that regarding assessment and diagnosis, also applies to progressive AOS.

The incidence of apraxia of speech (AOS) refers to the number of new cases identified in a specific time period. The prevalence of AOS refers to the number of individuals who are living with AOS in a given time period. 

There are no reliable data on the incidence and prevalence AOS in adults due to challenges associated with the common co-occurrence of AOS with aphasia and dysarthria (Duffy, 2006; Duffy et al., 2014). Collection of data is also challenging due to difficulty distinguishing among those disorders—particularly in distinguishing between AOS characteristics and phonological errors that can occur in aphasia (McNeil et al., 2004).

McNeil et al. (2009) suggest that isolated AOS (i.e., AOS in the absence of dysarthria or aphasia) is very uncommon. Duffy (2013) observed that AOS was documented as the primary, but not necessarily the only, communication disorder for 6.9% of all motor speech disorders in the Mayo Clinic Speech Pathology practice. This percentage would undoubtedly increase drastically if the data included cases in which AOS was a secondary communication disorder (e.g., less severe than aphasia or dysarthria; Duffy, 2013; pp. 269–270).

The salient features of apraxia of speech (AOS) that have gained broad consensus for differential diagnosis (Allison et al., 2020; Ballard et al., 2014; Duffy, 2013; McNeil et al., 2009) include

  • phoneme distortions and distorted substitutions or additions,
  • reduced overall speech rate,
  • syllable segregation with extended intra- and intersegmental durations, and
  • equal stress across adjacent syllables.

The above features are consistent with deficits in planning and programming movements for speech and may increase with greater syllable length and motoric complexity. AOS can improve, remain stable, or worsen depending on specific diagnosis and time elapsed since onset (e.g., primary progressive AOS vs. acute stroke recovery).

Other Perceptual Speech Characteristics

The following speech characteristics may not be unique to AOS and can occur in the presence or absence of coexisting dysarthria or aphasia.


  • voicing errors (blurred distinctions between boundaries of voiced–voiceless consonants)
  • prolonged phonemes
  • inconsistent errors
  • telescoping of syllables (e.g., “disaur” instead of “dinosaur”)

Rate and Prosody

  • slow overall rate
  • alternating motion rates (AMRs) that may be characterized by place or manner errors
  • poorly sequenced sequential motion rates (SMRs)


  • disrupted fluency with attempts at self-correction
  • difficulty initiating articulatory sequences—may be accompanied by audible or silent groping behaviors marking false starts and restarts
  • sound and syllable repetitions

Other Problems That Can Co-Occur With AOS

Linguistic and nonspeech/non-oromotor deficits may be comorbid to AOS and typically depend on the site of the lesion. These include the following:

  • Aphasia—language comprehension and/or production deficits.
  • Dysarthria—motor speech disorder characterized by neuromuscular weakness or impaired coordination or control. The type of dysarthria co-occurring with AOS varies considerably depending on the etiology, with unilateral upper motor neuron dysarthria likely occurring most often in AOS due to stroke.
  • Nonverbal oral apraxia—difficulty programming orofacial musculature for nonspeech movements.
  • Apraxia of swallowing—difficulty programming muscles of the head and neck for coordinated swallowing.
  • Limb apraxia—difficulty programming purposeful limb movements, often of both extremities.
  • Varying degrees of unilateral (typically right-sided) weakness and spasticity.

Acquired apraxia of speech (AOS) is caused by any process or condition that compromises the structures and pathways of the brain responsible for planning and programming motor movements for speech. Causes most often include

  • stroke,
  • traumatic brain injury (TBI),
  • tumor,
  • surgical trauma (e.g., tumor resection), or
  • progressive disease.

Occasionally, AOS is the first, only, or most prominent symptom in degenerative conditions (e.g., corticobasal degeneration, progressive supranuclear palsy). The term primary progressive AOS is used in such cases (Duffy, 2006; Duffy & McNeil, 2008; Duffy et al., 2007, 2020).

Speech-language pathologists (SLPs) play a central role in screening, assessment, diagnosis, and treatment of persons with apraxia of speech (AOS). The professional roles and activities in speech-language pathology include clinical services (diagnosis, assessment, planning, and treatment); prevention and advocacy; and education, administration, and research. See ASHA’s Scope of Practice in Speech-Language Pathology (American Speech-Language-Hearing Association [ASHA], 2016b).

The following roles are appropriate for SLPs when treating persons with AOS:

  • Providing prevention information to individuals and groups at risk for AOS, as well as to service providers.
  • Educating other professionals on the needs of persons with AOS and the role that SLPs play in meeting those needs.
  • Screening individuals to determine the need for further assessment and/or referral for other services.
  • Conducting a culturally and linguistically relevant comprehensive assessment of speech, language, and communication.
  • Diagnosing the presence of AOS and establishing its severity and prognosis.
  • Using dynamic assessment for differential diagnosis.
  • Providing intervention and management of symptoms.
  • Referring to, and collaborating with, other professionals to determine the etiology of AOS and to facilitate access to comprehensive services.
  • Making decisions, as part of the interdisciplinary team, regarding eligibility for services.
  • Developing culturally and linguistically appropriate treatment plans, providing intervention and support services, documenting progress, and determining appropriate service delivery approaches and dismissal criteria.
  • Serving as a key member of an interdisciplinary team that includes individuals with AOS and their families/caregivers.
  • Counseling persons with AOS and their families/caregivers regarding communication-related issues and providing education aimed at preventing further complications related to AOS.
  • Planning for augmentative and alternative communication (AAC) in a timely manner in the case of progressive AOS.
  • Consulting and collaborating with other professionals, families/caregivers, and others to facilitate program development and to provide supervision, evaluation, and/or expert testimony, as appropriate.
  • Remaining informed of research in the area of AOS, helping advance the knowledge base related to the nature and treatment of this disorder, and using evidence-based practice to guide intervention.
  • Advocating for individuals with AOS and their families at the local, state, and national levels.

As indicated in the ASHA Code of Ethics (ASHA, 2016a), SLPs who serve this population should be appropriately trained to do so. SLPs who diagnose and treat AOS must possess skills in differential diagnosis of motor speech disorders and comorbid language disorders, have specialized knowledge in phonological encoding disorders and motor learning theory, and have experience with appropriate intervention techniques.

See the Assessment section of the Apraxia of Speech (Adults) Evidence Map for pertinent scientific evidence, expert opinion, and client/caregiver perspective.


Screening identifies the need for further assessment and may be completed prior to a comprehensive evaluation. Screening can be completed using nonstandardized procedures. There are no apraxia of speech (AOS)–specific standardized screening tools available to date.

During screening, SLPs also look for signs of comorbid language, cognitive-communication, and swallowing deficits associated with the neurological insult.

It is best practice to complete a hearing screening to rule out hearing loss that might affect testing. If the individual wears hearing aids, the devices need to be inspected to ensure that they are in working order, and they need to be worn during screening.

Results of screening procedures are interpreted within the context of the individual’s cognitive–linguistic and sensory deficits. Screenings are ideally conducted in the language(s) used by the person, with sensitivity to cultural and linguistic diversity.

Screening may result in recommendations for

  • rescreening,
  • comprehensive assessments, and/or
  • referral for other examinations or services.

Comprehensive Assessment

A comprehensive assessment is conducted for individuals suspected of having AOS and uses both standardized and nonstandardized measures (see assessment tools, techniques, and data sources).

Consistent with the World Health Organization’s (WHO) International Classification of Functioning, Disability and Health framework (ASHA, 2016b; WHO, 2001), comprehensive assessment of individuals with AOS is conducted to identify and describe

  • impairments in body structure and function, including underlying strengths and weaknesses in speech sound production and verbal/nonverbal communication;
  • comorbid deficits such as other types of apraxia, aphasia, and dysarthria;
  • limitations in activity and participation, including functional status in communication, interpersonal interactions, self-care, and learning;
  • contextual (environmental and personal) factors that serve as barriers to, or facilitators of, successful communication and life participation; and
  • quality-of-life issues due to communication impairments and functional limitations relative to premorbid level of function, as well as social and community involvement.

See Person-Centered Focus on Function: Acquired Apraxia of Speech [PDF] for an example of assessment data consistent with the International Classification of Functioning, Disability and Health framework.

Comprehensive assessment focuses on functional aspects of speech generation:

  • Intelligibility—the degree to which listeners understand the acoustic signal produced by the individual.
  • Comprehensibility—the degree to which a listener understands the individual based on the acoustic signal plus other linguistic and nonspeech cues.
  • Efficiency—the rate at which the individual communicates an intelligible or comprehensible utterance; critical to setting meaningful functional targets in treatment planning.

Comprehensive assessment typically includes the following features:

Case History

This includes a review of current medical status, medical history, surgical history, prior level of function, education, occupation, and cultural and linguistic background. A case history may address activity/participation, contextual, and quality-of-life issues.

Self-Reported Areas of Concern

An SLP may evaluate functional communication status and the psychosocial impact of a given medical condition on the patient and caregiver(s) and identify meaningful functional goals for the individual and caregiver(s). An SLP may also identify communication difficulties, contexts of concern (e.g., social interactions, work activities), language(s) used in those contexts, and the individual’s goals and preferences.

Identification of Contextual Barriers and Facilitators

  • Facilitators—Examples are ability and willingness to use low- and high-tech augmentative and alternative communication systems (AAC), family support, and motivation to return to prior level of function.
  • Barriers—Examples are reduced confidence in verbal communication, cognitive deficits, and visual and motor impairments.

The identification of such barriers and facilitators assists the SLP in determining the potential for effective use of compensatory techniques and strategies, including the use of AAC.

Sensory and Motor Status

A person’s sensory and motor status may affect their ability to access nonspeech communication methods (e.g., writing, using gestures). Therefore, these factors may influence performance on speech assessment tasks. Consultation with members of the interdisciplinary team (e.g., occupational therapy) may be valuable.

Oral–Motor Mechanisms and Nonspeech Oral Praxis

This pertains to the integrity of the structure and function of the respiratory, phonatory, resonatory, and articulatory (lips, tongue, velum, hard palate, dentition) systems. Oral–motor mechanisms and nonspeech oral praxis includes the strength, speed, and range of movement of the components of the oral–motor system. It also refers to steadiness, tone, accuracy, and coordination of movements for speech and nonspeech tasks. Assessment of these systems is useful in differentiating AOS from dysarthria and oral apraxia.

Perceptual Speech Characteristics

This pertains to salient features of speech that aid in differential diagnosis (see the Differential Diagnosis section below). This includes analysis of the perceptual correlates of the respiratory, phonatory, resonatory, and articulatory subsystems. Analysis of such characteristics may use standardized and/or nonstandardized assessment and may include analysis of natural communication samples gathered in different modalities (i.e., speaking or reading) and contexts (i.e., social, educational, or vocational), as well as more structured tasks (e.g., imitative speech tasks, multiple repetitions of multisyllabic words). The SLP may also examine the influence of stress and/or fatigue on verbal communication (e.g., influence of physiologic and contextual factors that impact communication success).

Voice and Resonance Assessment

Abnormal features of voice and resonance (e.g., harsh, breathy, weak voice; hypernasality, hyponasality) are typically absent in isolated AOS. Analysis of voice may help differentiate AOS from dysarthria. See the Differential Diagnosis section below.

Language Assessment

Language assessment consists of expressive and receptive language. Analysis of language may help differentiate AOS from aphasia. See the Differential Diagnosis section below. 

Motor Speech Planning

AOS results from an impaired ability to plan commands that direct the correct movements for speech (Duffy, 2013). Assessment of motor speech planning includes the production of stimuli of differing motoric complexity—phonemes, syllables, monosyllabic/multisyllabic words, and sentences that place varying demands on the speech motor system. Motor speech planning assessment contrasts the following items:

  • oral/nasal versus voiced distinction
  • consonant clusters across syllables versus within syllables
  • stressed versus unstressed syllables and words
  • automatic/reactive versus volitional/propositional speech
  • imitation versus self-generated responses

Assessment of motor speech planning also examines the following:

  • Contextual speech—to assess integrated functioning of all the speech subsystems.
  • Vowel prolongation—to examine respiratory–phonatory coordination and vocal quality.
  • Diadochokinetic rates—to measure the repetition of specific sounds in a given period of time. These include
    • alternating motion rates—to judge speed and regularity of movement of articulators (e.g., /papapa/); and
    • sequential motion rates—to evaluate the ability to move quickly and sequentially from one articulatory posture to another, an impairment that is particularly characteristic of AOS (e.g., /pataka/).
  • Acoustic and physiologic assessments—using instrumental and perceptual procedures to quantify abnormalities in voice onset time, rate, prosody and stress, articulation, and trial-to-trial variability.

Assessment Results

Assessment may result in the following outcomes:

  • Diagnosis of AOS.
  • Clinical description of the characteristics and severity of the disorder.
  • Statement of prognosis and recommendations for intervention that relate to overall communication adequacy, including AAC measures as needed. See ASHA’s Practice Portal page on Augmentative and Alternative Communication.
  • Identification of relevant follow-up services for appropriate intervention and support for individuals with AOS.
  • Referral to other professionals as needed—including, for example, the following professionals:
    • occupational therapist—for nonspeech, sensory–motor, or fine motor issues
    • physical therapist—if gross motor skills or overall muscle tone is of concern
    • neurologist—if the causal diagnosis is uncertain or if other neurological signs or symptoms are identified that require further investigation or management.

Differential Diagnosis

AOS often co-occurs with or presents similarly to other neurogenic communication disorders such as dysarthria and aphasia. AOS does not involve muscle weakness, paralysis, spasticity, or involuntary movements typically associated with dysarthria or language comprehension or production deficits that characterize aphasia.

Differential diagnosis between these conditions and AOS is essential. The chart below provides a basic comparison between characteristics of these disorders.

Characteristic AOS Dysarthria Aphasia
Muscle weakness No Yes No
Articulatory deficits Yes Yes No
Prosodic deficits Yes Yes No
Language processing deficits No No Yes
Consistent error patterns* No Yes No
Groping for articulatory postures Yes No No

*See the “Distinguishing AOS From Aphasia” section below for further details.

Please note that the chart above does not capture all the nuances of differential diagnosis of AOS. Information below may further clarify this subject.

Distinguishing AOS From Dysarthria

The dysarthria subtypes that are most difficult to distinguish from AOS are ataxic and unilateral upper motor neuron dysarthria, and the latter may often co-occur with AOS. Poorer performance on sequential motion rates (SMRs) than on alternating motion rates (AMRs) in AOS may distinguish it from ataxic dysarthria (Duffy, 2013). Examination of speech subsystems using speech—and, sometimes, nonspeech—tasks is crucial in distinguishing AOS from dysarthria. AOS is primarily marked by articulatory and prosodic deficits, unlike dysarthria in which other speech subsystems can be affected—most notably, resonance. Unlike AOS, dysarthria is generally not influenced by automaticity of speech production, stimulus modality, and linguistic variables (Duffy, 2013).

Distinguishing AOS From Aphasia

AOS may be difficult to differentiate from aphasia in its clinical presentation, and the conditions frequently co-occur. Duffy (2013) notes distinctions between AOS and aphasia (e.g., prosodic errors, language processing deficits) reflected in the comparison chart above.

Aphasia may be so severe that AOS may be masked during assessment. Although speech sound errors are thought to arise from different processing impairments (motor planning deficits in AOS vs. linguistic breakdowns in aphasia), error patterns are often similar, particularly in very mild or very severe presentations. Temporal acoustic characteristics of speech help distinguish AOS from aphasia better than perceptual characteristics alone (Haley et al., 2012). Nevertheless, many people with speech sound errors following a neurological injury may not be easily classifiable, with borderline presentations possible similar to both AOS and aphasia with phonemic paraphasia (Haley et al., 2017). Speech error patterns have, at various times, been described as consistent or inconsistent in speakers with AOS and considered as a potential diagnostic feature (see, e.g., McNeil et al., 2009; Wertz et al., 1984). However, recent evidence concludes that error consistency is often present both in people with AOS and in people with aphasia without AOS and is therefore not useful for differential diagnosis (Haley et al., 2020).

Assessment Considerations: Progressive Conditions

Periodic reassessment of individuals with AOS is important because neurological recovery can occur for several months or longer in the context of acquired AOS. Ongoing assessment can also be used to examine an individual’s responses to rehabilitation and to life adaptations after the injury. Progressive conditions such as primary progressive AOS require periodic reassessment to ensure that the individual is communicating at maximal levels of independence and to plan for additional communication adaptations that may become necessary with disease progression.

Assessment Considerations: Cultural and Linguistic Factors

The SLP considers the influence of cultural and linguistic factors on the individual’s communication style and the potential impact of impairment on function when selecting screening and assessment tests. The assessment is conducted in the language(s) used by the person with AOS, with the use of interpretation services as necessary (see collaborating with interpreters, transliterators, and translators).

Although the impact of AOS on speech changes is the same across languages (i.e., disrupted articulation and prosody), the impact on communication is different. For example, speakers of tonal languages may require special consideration when working with AOS, as AOS may contain prosodic deficits. Prosodic deficits in tonal languages may have the capacity to change the meaning of a given word.

Appropriate accommodations and modifications can be made to the testing process to reconcile cultural and linguistic variations. Comprehensive documentation includes descriptions of these accommodations and modifications. If a standardized test is modified or if accommodations are provided that are not allowed for in the assessment, standardized scores are invalid and inappropriate to report.

See the Treatment section of the Apraxia of Speech (Adults) Evidence Map for pertinent scientific evidence, expert opinion, and client/caregiver perspective.

The goal of intervention is to help the individual achieve the highest level of independent function for participation in daily living (WHO, 2001). Intervention is designed to

  • use strengths and address weaknesses related to underlying structures and functions that affect communication;
  • facilitate the individual’s activities and participation to develop new skills and strategies; and
  • eliminate barriers and enhance skills that increase successful communication and participation, including the development and use of appropriate accommodations.

For individuals with apraxia of speech (AOS), treatment goals focus on facilitating the efficiency, effectiveness, and naturalness of communication by

  • improving speech production and intelligibility and
  • using augmentative and alternative communication (AAC), such as gestures, manual signs, electronic speech output devices, and context-specific communication boards when indicated.

Barriers to successful communication and participation can be minimized for individuals with AOS by

  • modifying the environment (e.g., reducing background noise, maintaining eye contact, and decreasing the distance between speaker and listener);
  • informing listeners about the individual’s communication needs and their preferred method of communication; and
  • encouraging the speaker to use strategies for repairing breakdowns in communication (e.g., repeating, rephrasing, using gestures, writing).

See Person-Centered Focus on Function: Acquired Apraxia of Speech [PDF] for an example of functional goals consistent with the International Classification of Functioning, Disability and Health framework.

Family-Centered Practice

The goal of family-centered practice for individuals with AOS is to create a partnership so that family members fully participate in all aspects of the individual’s care. The range of services offered to families includes

  • counseling,
  • providing resources and information,
  • coordinating services,
  • advocating for practices that incorporate family preferences and address family priorities, and
  • teaching specific skills to family members and other significant communication partners (see family-centered practice).

Treatment Considerations

When designing a treatment program for an individual with AOS, consider the following factors:

Client Autonomy and Personal Preferences

  • Treatment begins with meaningful and self-selected speech stimuli (e.g., words and phrases).
  • The ability to exercise choice and control over practice conditions has been shown to enhance motor skill learning, even when choices are incidental (e.g., which target to practice first; Wulf & Lewthwaite, 2016).

    Task Difficulty

    • Stimulability is often used to determine initial therapy targets; however, more difficult targets may promote better generalization (Ballard, 2001; Maas et al., 2008; Odell, 2002).
    • Motor performance and learning may be enhanced by setting positive expectations that a learner will be able to complete a task (i.e., moderating perceived task difficulty; Wulf & Lewthwaite, 2016).

    Task Hierarchy

    • Consistent with the principles of motor learning, practice is hierarchical, and selection of stimulus targets promotes success at each step (Guadagnoli & Lee, 2004).
    • Tasks typically begin at the syllable level (Duffy, 2013; Schor et al., 2012; Ziegler et al., 2010) unless the individual has some success at the word or phrase level.
    • Single sounds (phonemes) or nonspeech oral–motor movement patterns that approximate speech gestures (e.g., lip rounding and tongue elevation) might be targeted initially if the individual is not yet capable of meaningful speech (Duffy, 2013), especially when oral apraxia is absent.
    • For individuals who are nonverbal, reflexive actions (e.g., cough, laugh) may be initially elicited as reflexes and then shaped to volitional control and, ultimately, to voluntary speech production (Simpson & Clark, 1989).
      Examples of Stimulus and Task Variables That Affect Responses*
      Easier More difficult
      Oral/nasal distinctions Voiced distinctions
      Bilabial and lingual/alveolar place of articulation Other places of articulation
      Consonant clusters that cross syllables Consonant clusters within syllables
      Shorter syllables Longer syllables
      High-frequency syllables and words Low-frequency syllables and words
      Stressed syllables and words Unstressed syllables and words
      Automatic/reactive speech Volitional/propositional speech
      Imitation of a model Self-generation of response (especially in those with coexisting aphasia)
      *Source: Duffy (2013).


      • Acquisition of new target behaviors may be enhanced by feedback that is frequent and specific.
      • Retention and generalization may be greater when feedback is intermittent rather than constant (e.g., 60% of the time) and more general or evaluative (e.g., that was correct or incorrect).
      • Both initial skill acquisition as well as retention and generalization are improved when there is a delay (e.g., 5 seconds) between response and feedback (Austermann Hula et al., 2008).
      • Learning may be enhanced when feedback is provided following correct responses in comparison to incorrect responses (Wulf & Lewthwaite, 2016).
      • Self-monitoring and self-correction can facilitate learning and maintenance of skills (Rosenbek et al., 1973).

      Treatment Approaches

      Treatment can be restorative (i.e., aimed at improving or restoring impaired function) and/or compensatory (i.e., aimed at compensating for deficits not amenable to retraining). In the case of progressive AOS, it may also help maintain speech functioning.

      Approaches aimed at improving speech production and intelligibility focus on reestablishing motor plans/programs and improving the ability to select and activate them and set program parameters (e.g., speed) in specific situations (Knock et al., 2000). These treatment approaches include articulatory–kinematic approaches, sensory cueing, rate and/or rhythm control, and various combinations thereof.

      Approaches used to compensate for AOS focus on teaching use of strategies or external aids and creating or personalizing those resources (e.g., using gestures, writing, or drawing to communicate).

      Some approaches may be used in both restorative and compensatory capacities. For example, AAC is used to provide functional communication options while supporting, enhancing, and potentially improving speech production (Lasker et al., 2008; Yorkston et al., 2010).

      Treatment Options

      Below are brief descriptions of treatment options for addressing AOS, grouped by approach. This list is not exhaustive, and the inclusion of any specific treatment does not imply endorsement from ASHA. Please see the Apraxia of Speech (Adults) Evidence Map for systematic reviews of AOS interventions.

      Treatment selection depends on a number of factors, including severity of the disorder, communication needs of the individual, and presence and severity of co-occurring conditions (e.g., aphasia and associated language and cognitive deficits, dysarthria, or progressive neurological diseases).

      Apraxia in other systems may play a role in treatment. For example, similar to limb weakness, the presence of limb apraxia may impact access to AAC.

      Articulatory–Kinematic Approaches

      Articulatory–kinematic approaches are based on principles of motor programming/planning. They

      • provide frequent and intensive practice of speech targets;
      • focus on accurate speech movement;
      • include external sensory input for speech production (e.g., auditory, visual, tactile, and cognitive cues);
      • consider practice schedules, such as random versus blocked practice (see, e.g., Wambaugh et al., 2014, 2016); and
      • provide appropriate types and schedules of feedback regarding performance.

      See Bislick et al. (2012) and Maas et al. (2008) for discussions of motor learning principles as they apply to the treatment of motor speech disorders.

      Multiple Input Phoneme Therapy

      Multiple input phoneme therapy is appropriate for individuals with severe AOS. The program proceeds through a hierarchy of steps that stress phoneme generalization using multiple input stimuli. The individual’s stereotypic utterances are used as initial stimuli; the clinician models these utterances while simultaneously providing a gestural/prosodic cue (e.g., tapping the individual’s arm). The clinician then fades the voice and mimes the movement while the individual continues to produce the target. New words use the initial phoneme of a stereotypic utterance (e.g., “one” to “win”). The number of targets and the length and phoneme complexity progressively increase. The individual initially repeats the stereotypic utterance in a nonvolitional manner and eventually regains volitional control and the ability to spontaneously express words and phrases (Stevens, 1989; Stevens & Glaser, 1983).

      Sound Production Treatment

      Sound production treatment is intended to improve production of consonants that are problematic for a particular speaker. It uses a treatment hierarchy that incorporates modeling and repetition of minimal-contrast word pairs. Auditory, visual, and tactile cues are used, along with articulatory placement cueing and graphemic cues (Wambaugh et al., 1998; Wambaugh & Mauszycki, 2010).

      Speech Motor Learning Treatment Approach

      The speech motor learning treatment approach addresses the underlying inability to plan and program the production of speech motor targets in varying phonetic contexts and in utterances longer than single words or nonwords. Nonwords, constructed from a corpus of target consonants and vowels, are used as treatment stimuli. Treatment proceeds in steps, taking the individual from imitated blocked practice of each nonword to self-initiated production of a series of nonwords. Eventually, real words and phrases containing these words are identified and rehearsed until the criterion is met (van der Merwe, 2011).

      Sensory Cueing Approaches

      Many treatments for AOS incorporate sensory input (e.g., visual, auditory, proprioceptive, and tactile cues) to teach the movement sequences for speech. Sensory cues can be used separately or in combination (i.e., multisensory approach). Feedback is an important aspect of motor learning. These external cues may facilitate speech production by providing additional feedback to the individual if they cannot benefit from, or do not receive, sufficient intrinsic sensory feedback.

      Integral Stimulation

      Integral stimulation is a method for practicing movement gestures for speech production that involves imitation and emphasizes multiple sensory models (e.g., auditory, visual, tactile). This method is part of many treatment approaches. Treatment follows a “listen to me, watch me, do what I do” sequence, in which the individual hears and sees how the clinician produces a targeted sound sequence or word/phrase and then imitates (Rosenbek et al., 1973).

      Tactile Cueing

      Tactile cueing methods of speech facilitation are those that provide direct tactile input for correct speech production. Using these methods, the SLP applies pressure or otherwise touches the individual’s face, neck, and head to provide a tactile cue for correct production or speech movement gesture.

      Prompts for Restructuring Oral Muscular Phonetic Targets (PROMPT)

      PROMPT is a tactile method of treatment based on touch pressure, kinesthetic, and proprioceptive cues (Bose et al., 2001; Chumpelik, 1984; Freed et al., 1997). Using this approach, the clinician uses finger placements on the individual’s face and neck to cue various aspects of speech production (e.g., place and manner of articulation) and help the individual limit unnecessary movements. PROMPT requires specialized training.

      Visual Cueing

      Visual cueing methods provide visual cues for shape, placement, or movement of the articulators. Visual cues can be provided via low-tech methods (e.g., simple hand signs or visual feedback via a mirror) or more technologically advanced methods that utilize computer software and screen, ultrasound images, and other forms of biofeedback (e.g., acoustic/spectrographic feedback displays).


      Electropalatography utilizes a palatal device with electrodes to record and visualize contact of the tongue on the palate while an individual makes different speech sounds (Howard & Varley, 1995). Electropalatography provides real-time visual feedback as well as a split-screen option so that the SLP can model the correct tongue placement while the patient observes.

      Electromagnetic Articulography

      Electromagnetic articulography uses miniature receiver coils placed on and in the mouth (e.g., tongue dorsum, corners of the mouth, or velar margin) to record and provide a visual display of tongue, mouth, palate, and jaw movements during treatment. AOS treatment research involving electromagnetic articulography has focused on tongue placement (see, e.g., Katz et al., 1999, 2010).

      Word and Phrase–Focused Approaches

      Script Training

      Script training is a functional approach to treating neurogenic communication disorders (Holland et al., 2002). It is used to facilitate verbal communication on specific topics selected by the individual. Script training helps the individual who wants to speak relatively normally on a few personally relevant topics. A number of phrases are practiced so that they become automatic and can be inserted into conversation relatively fluently (Henry et al., 2018; Youmans et al., 2011).

      Rate and Rhythm Control Approaches

      Rate and rhythm control approaches (also called prosodic facilitation approaches) use intonation patterns (melody, rhythm, and stress) to improve speech production. Although these approaches are aimed at improving prosody, they may also result in improved articulation for individuals with AOS (Mauszycki & Wambaugh, 2011). Using these patterns, the clinician guides the individual through a gradual progression of steps that increase the length of utterances, decrease dependence on the clinician, and decrease reliance on intonation (Martin et al., 2001).

      Contrastive Stress

      Contrastive stress is used when speaking to highlight a particular word in a phrase or sentence; varying the stressed word also changes the meaning of the sentence. In treating AOS, contrastive stress can be used in target phrases or sentences to improve the individual’s ability to produce speech with varying intonation contours (Wertz et al., 1984).

      Melodic Intonation Therapy

      Melodic intonation therapy uses melody, rhythm, and stress to facilitate speech production. The clinician provides models of intoned utterances of varying lengths. Reliance on intonation is gradually decreased over time. Melodic intonation therapy was first designed for individuals with nonfluent aphasia, many of whom have co-occurring AOS (Sparks et al., 1974; Sparks & Holland, 1976; Zumbansen et al., 2014).

      Metrical Pacing Treatment

      Metrical pacing treatment is a pacing technique that uses rhythmical sequences of tones that provide metrical templates to guide the production of target utterances. Individuals are asked to produce target utterances at the same time as pacing signals. The synchronization pulse is generated by a computer and can be varied by rate (corresponding to speech rate) and metrical structure (syllable number and stress pattern) to simulate natural stress patterns of speech (Brendel & Ziegler, 2008).

      Rhythmic Pacing Strategies

      Rhythmic pacing strategies use various rate control techniques to provide temporal cues that help pace speech production. Techniques include hand or finger tapping and use of a pacing board or metronome (Dworkin et al., 1988; Mauszycki & Wambaugh, 2008).

      Transcranial Direct Current Stimulation

      Transcranial direct current stimulation is an experimental procedure in which transcranial direct current is delivered to the left inferior frontal gyrus to modulate cortical activity. It has been used in conjunction with articulatory–kinematic treatment to improve the speech of individuals with AOS secondary to stroke. Speech targets consist of syllables and words that are presented auditorily and are repeated by the individual (Marangolo et al., 2011).

      Augmentative and Alternative Communication (AAC)

      AAC involves supplementing or replacing natural spoken language with writing and/or aided (e.g., picture communication, line drawings, speech-generating devices, and tangible objects) or unaided (e.g., manual signs, gestures, and finger spelling) symbols. Whereas aided symbols require some type of transmission device, the production of unaided symbols requires only body movements. When selecting AAC systems or devices, it is important to determine the individual’s willingness to use them. See Lasker and Bedrosian (2001) for a discussion on promoting acceptance of AAC by adults with acquired communication disorders. See ASHA’s Practice Portal page on Augmentative and Alternative Communication for additional information.

      Treatment Considerations: Factors Influencing Treatment Decisions

      Severity of co-occurring conditions may influence treatment decisions. For example, improving the functional communication of an individual with severe language and cognitive impairments following a stroke may take precedence over treatment of their AOS. Treatment for individuals with progressive AOS resulting from degenerative disease is often appropriate, particularly for those with no significant language or cognitive impairments. The goal of treatment is to maximize communication at each stage of the disease, not to reverse decline (Duffy, 2013). Goals in the early stages might begin with efforts to improve speech and maintain comprehensibility, followed by establishing the use of compensatory strategies, including AAC (Duffy & McNeil, 2008; Jung et al., 2013).

      Service Delivery

      In addition to determining the optimal speech and language treatment for an individual with AOS, the clinician considers other service delivery variables that may have an impact on treatment outcomes, such as format, provider, dosage, timing, and setting.


      Format refers to the structure of the treatment session (e.g., group and/or individual). The appropriateness of treatment format (individual vs. group vs. both) depends on the primary goal at a particular point in the treatment process. For example, initial treatment may involve intensive drills to improve speech production and/or practice in using AAC aids. However, once the individual has made progress on these goals, group treatment may be incorporated to provide opportunities for practice.


      Provider refers to the person providing the treatment (e.g., SLP, trained volunteer, caregiver). SLPs treat the speech motor and communication aspects of AOS and train individuals in the use of AAC. It is important to involve family members, caregivers, and other communication partners in the treatment process to help them understand the individual’s communication needs and learn strategies to facilitate communication. Other professionals (e.g., physical therapist or occupational therapist) may be involved in the treatment of comorbid deficits. It is important for SLPs to collaborate with other professionals regarding treatment and to take advantage of opportunities for co-treatment.


      Dosage refers to the frequency, intensity, and duration of service. Treatment dosage for AOS should be consistent with principles of motor learning (Maas et al., 2008; Rosenbek et al., 1973; Wambaugh et al., 2014). Intensive and individualized treatment is often stressed because of the need for repetitive production practice in motor speech disorders like AOS. See Ballard et al. (2015) for a discussion of average dosage.


      Timing refers to the initiation of intervention relative to diagnosis. Generally speaking, treatment begins as early as possible post onset. Treatment can also be appropriate when an extended amount of time has elapsed since onset, particularly if an individual has not received any treatment for AOS during that time.


      Setting refers to the location of treatment (e.g., home, community-based). A naturalistic treatment environment that incorporates a variety of communication partners may facilitate generalization and carryover of skills.

      Allison, K. M., Cordella, C., Iuzzini-Seigel, J., & Green, J. R. (2020). Differential diagnosis of apraxia of speech in children and adults: A scoping review. Journal of Speech, Language, and Hearing Research, 63(9), 2952–2994.

      American Speech-Language-Hearing Association. (2016). Scope of practice in speech-language pathology [Scope of practice].

      American Speech-Language-Hearing Association. (2023). Code of ethics [Ethics].

      Austermann Hula, S. N., Robin, D. A., Maas, E., Ballard, K. J., & Schmidt, R. A. (2008). Effects of feedback frequency and timing on acquisition, retention, and transfer of speech skills in acquired apraxia of speech. Journal of Speech, Language, and Hearing Research, 51(5), 1088–1113.

      Ballard, K. J. (2001). Response generalization in apraxia of speech treatments: Taking another look. Journal of Communication Disorders, 34(1–2), 3–20.

      Ballard, K. J., Tourville, J., & Robin, D. A. (2014). Behavioral, computational, and neuroimaging studies of acquired apraxia of speech. Frontiers in Human Neuroscience, 8, 1–9.

      Ballard, K. J., Wambaugh, J. L., Duffy, J. R., Layfield, C., Maas, E., Mauszycki, S., & McNeil, M. R. (2015). Treatment for acquired apraxia of speech: A systematic review of intervention research between 2004 and 2012. American Journal of Speech-Language Pathology, 24(2), 316–337.

      Bislick, L. P., Weir, P. C., Spencer, K., Kendall, D., & Yorkston, K. M. (2012). Do principles of motor learning enhance retention and transfer of speech skills? A systematic review. Aphasiology, 26(5), 709–728.

      Bose, A., Square, P. A., Schlosser, R., & van Lieshout, P. (2001). Effects of PROMPT therapy on speech motor function in a person with aphasia and apraxia of speech. Aphasiology, 15(8), 767–785.

      Brendel, B., & Ziegler, W. (2008). Effectiveness of metrical pacing in the treatment of apraxia of speech. Aphasiology, 22(1), 77–102.

      Chumpelik, D. (1984). The PROMPT system of therapy: Theoretical framework and applications for developmental apraxia of speech. Seminars in Speech and Language, 5(2), 139–156.

      Duffy, J. R. (2006). Apraxia of speech in degenerative neurologic disease. Aphasiology, 20(6), 511–527.

      Duffy, J. R. (2013). Motor speech disorders: Substrates, differential diagnosis, and management. Mosby.

      Duffy, J. R., & McNeil, M. R. (2008). Primary progressive aphasia and apraxia of speech. In R. Chapey (Ed.), Language intervention strategies in aphasia and related neurogenic communication disorders (pp. 543–564). Lippincott Williams & Wilkins.

      Duffy, J. R., Peach, R. K., & Strand, E. A. (2007). Progressive apraxia of speech as a sign of motor neuron disease. American Journal of Speech-Language Pathology, 16(3), 198–208.

      Duffy, J. R., Strand, E. A., & Josephs, K. A. (2014). Motor speech disorders associated with primary progressive aphasia. Aphasiology, 28(8–9), 1004–1017.

      Duffy, J. R., Utianski, R. L., & Josephs, K. A. (2020). Primary progressive apraxia of speech: From recognition to diagnosis and care. Aphasiology. Advance online publication.

      Dworkin, J. P., Abkarian, G. G., & Johns, D. F. (1988). Apraxia of speech: The effectiveness of a treatment regimen. Journal of Speech and Hearing Disorders, 53(3), 280–294.

      Freed, D. B., Marshall, R. C., & Frazier, K. E. (1997). Long-term effectiveness of PROMPT treatment in a severely apractic-aphasic speaker. Aphasiology, 11(4–5), 365–372.

      Guadagnoli, M. A., & Lee, T. D. (2004). Challenge point: A framework for conceptualizing the effects of various practice conditions in motor learning. Journal of Motor Behavior, 36(2), 212–224.

      Haley, K. L., Cunningham, K. T., Jacks, A., Richardson, J. D., Harmon, T., & Turkeltaub, P. E. (2020). Repeated word production is inconsistent in both aphasia and apraxia of speech. Aphasiology. Advance online publication.

      Haley, K. L., Jacks, A., de Riesthal, M., Abou-Khalil, R., & Roth, H. L. (2012). Toward a quantitative basis for assessment and diagnosis of apraxia of speech. Journal of Speech, Language, and Hearing Research, 55(5), S1502–S1517.

      Haley, K. L., Jacks, A., Richardson, J. D., & Wambaugh, J. L. (2017). Perceptually salient sound distortions and apraxia of speech: A performance continuum. American Journal of Speech-Language Pathology, 26(2S), 631–640.

      Henry, M. L., Hubbard, H. I., Grasso, S. M., Mandelli, M. L., Wilson, S. M., Sathishkumar, M. T., Fridriksson, J., Daigle, W., Boxer, A. L., Miller, B. L., & Gorno-Tempini, M. L. (2018). Retraining speech production and fluency in non-fluent/agrammatic primary progressive aphasia. Brain, 141(6), 1799–1814.

      Holland, A., Milman, L., Munoz, M., & Bays, G. (2002, June). Scripts in the management of aphasia [Paper presentation]. World Federation of Neurology Aphasia and Cognitive Disorders Section Meeting, Villefranche, France.

      Howard, S., & Varley, R. (1995). III: EPG in therapy using electropalatography to treat severe acquired apraxia of speech. European Journal of Disorders of Communication, 30(2), 246–255.

      Jung, Y., Duffy, J. R., & Josephs, K. A. (2013). Primary progressive aphasia and apraxia of speech. Seminars in Neurology, 33(4), 342–347.

      Katz, W. F., Bharadwaj, S. V., & Carstens, B. (1999). Electromagnetic articulography treatment for an adult with Broca’s aphasia and apraxia of speech. Journal of Speech, Language, and Hearing Research, 42(6), 1355–1366.

      Katz, W. F., McNeil, M. R., & Garst, D. M. (2010). Treating apraxia of speech (AOS) with EMA-supplied visual augmented feedback. Aphasiology, 24(6–8), 826–837.

      Knock, T. R., Ballard, K. J., Robin, D. A., & Schmidt, R. A. (2000). Influence of order of stimulus presentation on speech motor learning: A principled approach to treatment for apraxia of speech. Aphasiology, 14(5–6), 653–668.

      Lasker, J. P., & Bedrosian, J. L. (2001). Promoting acceptance of augmentative and alternative communication by adults with acquired communication disorders. Augmentative and Alternative Communication, 17(3), 141–153.

      Lasker, J. P., Stierwalt, J. A. G., Hageman, C. F., & LaPointe, L. L. (2008). Using motor learning guided theory and augmentative and alternative communication to improve speech production in profound apraxia: A case example. Journal of Medical Speech-Language Pathology, 16(4), 225–233.

      Maas, E., Robin, D. A., Austermann Hula, S. N., Freedman, S. E., Wulf, G., Ballard, K. J., & Schmidt, R. A. (2008). Principles of motor learning in treatment of motor speech disorders. American Journal of Speech-Language Pathology, 17(3), 277–298.

      Marangolo, P., Marinelli, C. V., Bonifazi, S., Fiori, V., Ceravolo, M. G., Provinciali, L., & Tomaiuolo, F. (2011). Electrical stimulation over the left inferior frontal gyrus (IFG) determines long-term effects in the recovery of speech apraxia in three chronic aphasics. Behavioural Brain Research, 225(2), 498–504.

      Martin, V. C., Kubitz, K. R., & Maher, L. M. (2001). Melodic intonation therapy. Perspectives on Neurophysiology and Neurogenic Speech and Language Disorders, 11(3), 33–37.

      Mauszycki, S. C., & Wambaugh, J. L. (2008). The effects of rate control treatment on consonant production accuracy in mild apraxia of speech. Aphasiology, 22(7–8), 906–920.

      Mauszycki, S. C., & Wambaugh, J. L. (2011, May). Acquired apraxia of speech: A treatment overview. The ASHA Leader, 16(5), 16–19.

      McNeil, M. R., Pratt, S. R., & Fossett, T. R. (2004). The differential diagnosis of apraxia of speech. In B. Maassen, R. Kent, H. Peters, P. van Lieshout, & W. Hulstijn (Eds.), Speech motor control in normal and disordered speech (pp. 389–413). Oxford University Press.

      McNeil, M. R., Robin, D. A., & Schmidt, R. A. (2009). Apraxia of speech: Definition and differential diagnosis (2nd ed.). In M. R. McNeil (Ed.), Clinical management of sensorimotor speech disorders (pp. 249–268). Thieme.

      Odell, K. H. (2002). Considerations in target selection in apraxia of speech treatment. Seminars in Speech and Language, 23(4), 309–324.

      Rosenbek, J., Lemme, M., Ahern, M., Harris, N., & Wertz, T. (1973). A treatment for apraxia of speech in adults. Journal of Speech and Hearing Disorders, 38(4), 462–472.

      Schor, A., Aichert, I., & Ziegler, W. (2012). A motor learning perspective on phonetic syllable kinships: How training effects transfer from learned to new syllables in severe apraxia of speech. Aphasiology, 26(7), 880–894.

      Simpson, M. B., & Clark, A. R. (1989). Clinical management of apractic mutism. In P. Square-Storer (Ed.), Acquired apraxia of speech in aphasic adults (pp. 241–266). Taylor & Francis.

      Sparks, R., Helm, N., & Albert, M. (1974). Aphasia rehabilitation resulting from melodic intonation therapy. Cortex, 10(4), 303–316.

      Sparks, R., & Holland, A. (1976). Method: Melodic intonation therapy for aphasia. Journal of Speech and Hearing Disorders, 41(3), 287–297.

      Stevens, E. R. (1989). Multiple input phoneme therapy. In P. Square-Storer (Ed.), Acquired apraxia of speech in aphasic adults (pp. 220–238). Taylor & Francis.

      Stevens, E. R., & Glaser, L. E. (1983). Multiple input phoneme therapy: An approach to severe apraxia and expressive aphasia. In R. H. Brookshire (Ed.), Clinical Aphasiology Conference Proceedings (pp. 148–155). BRK Publishers.

      van der Merwe, A. (2011). A speech motor learning approach to treating apraxia of speech: Rationale and effects of intervention with an adult with acquired apraxia of speech. Aphasiology, 25(10), 1174–1206.

      Wambaugh, J. L., Kalinyak-Fliszar, M. M., West, J. E., & Doyle, P. J. (1998). Effects of treatment for sound errors in apraxia of speech and aphasia. Journal of Speech, Language, and Hearing Research, 41(4), 725–743.

      Wambaugh, J. L., & Mauszycki, S. C. (2010). Sound production treatment: Application with severe apraxia of speech. Aphasiology, 24(6–8), 814–825.

      Wambaugh, J. L., Nessler, C., Wright, S., & Mauszycki, S. (2014). Sound production treatment: Effects of blocked and random practice. American Journal of Speech-Language Pathology, 23(2), 225–245.

      Wambaugh, J. L., Nessler, C., Wright, S., Mauszycki, S., & DeLong, C. (2016). Sound production treatment for acquired apraxia of speech: Effects of blocked and random practice on multisyllabic word production. International Journal of Speech-Language Pathology, 18(5), 450–464.

      Wertz, R. T., LaPointe, L. L., & Rosenbek, J. C. (1984). Apraxia of speech in adults: The disorder and its management. Grune & Stratton.

      World Health Organization. (2001). International Classification of Functioning, Disability and Health.

      Wulf, G., & Lewthwaite, R. (2016). Optimizing performance through intrinsic motivation and attention for learning: The OPTIMAL theory of motor learning. Psychonomic Bulletin & Review, 23(5), 1382–1414.

      Yorkston, K. M., Beukelman, D. R., Strand, E. A., & Hakel, M. (2010). Management of motor speech disorders in children and adults. Pro-Ed.

      Youmans, G., Youmans, S. R., & Hancock, A. B. (2011). Script training treatment for adults with apraxia of speech. American Journal of Speech-Language Pathology, 20(1), 23–37.

      Ziegler, W., Aichert, I., & Staiger, A. (2010). Syllable- and rhythm-based approaches in the treatment of apraxia of speech. Perspectives on Neurophysiology and Neurogenic Speech and Language Disorders, 20(3), 59–66.

      Zumbansen, A., Peretz, I., & Hébert, S. (2014). Melodic intonation therapy: Back to basics for future research. Frontiers in Neurology, 5, 1–11.


      Content for ASHA's Practice Portal is developed through a comprehensive process that includes multiple rounds of subject matter expert input and review. ASHA extends its gratitude to the following subject matter experts who were involved in the development of the Acquired Apraxia of Speech page:

      • Kirrie J. Ballard, PhD, CCC-SLP
      • Heather M. Clark, PhD, CCC-SLP
      • Shannon Cook Mauszycki, PhD, CCC-SLP
      • Joseph R. Duffy, PhD, CCC-SLP
      • Katarina Haley, PhD, CCC-SLP
      • Adam Jacks, PhD, CCC-SLP
      • Edwin Maas, PhD
      • Malcolm R. McNeil, PhD, CCC-SLP
      • Christina Nessler, MS, CCC-SLP
      • Edythe A. Strand, PhD, CCC-SLP
      • Rene Utianski, PhD, CCC-SLP
      • Darlene S. Williamson, MA, CCC-SLP

      Citing Practice Portal Pages

      The recommended citation for this Practice Portal page is:

      American Speech-Language-Hearing Association. (n.d.). Acquired Apraxia of Speech. (Practice Portal). Retrieved month, day, year, from

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