Dysarthria in Adults


See the Assessment section of the Dysarthria Evidence Map for pertinent scientific evidence, expert opinion, and client/caregiver perspectives.

Screening

Screening for dysarthria is pass/fail. It does not provide a diagnosis or a detailed description of the severity and characteristics of speech deficits associated with dysarthria but, rather, identifies the need for further assessment.

Screening may result in recommendations for

  • dysarthria assessment and/or
  • referral for other examinations or services.

Dysarthria Assessment

Assessment of individuals with suspected dysarthria should be conducted by an SLP using both standardized and nonstandardized measures (see assessment tools, techniques, and data sources).

The goal of the dysarthria assessment is to

  • describe perceptual characteristics of the individual's speech and relevant physiologic findings;
  • describe speech subsystems affected (i.e., articulation, phonation, respiration, resonance, and prosody) and the severity of impairment for each;
  • identify other systems and processes that may be affected (e.g., swallowing, language, cognition); and
  • assess the impact of the dysarthria on speech intelligibility and naturalness, communicative efficiency and effectiveness, and participation.

See, for example, Duffy (2013) and Lowit and Kent (2010).

The severity of the disorder does not necessarily determine the degree of disability. Speech-related disability will depend on the communication needs of the individual and the comprehensibility of his or her speech in salient contexts.

Consistent with the World Health Organization's (WHO) International Classification of Functioning, Disability, and Health (ICF) framework (ASHA, 2016b; WHO, 2001), the assessment identifies and describes

  • impairments in body structure and function, including underlying strengths and weaknesses in speech production and verbal/nonverbal communication;
  • the individual's 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
  • the impact of communication impairments on quality of life and functional limitations relative to the individual's premorbid social roles and abilities and the impact on his or her community.

See Person-Centered Focus on Function: Dysarthria [PDF] for an example of assessment data consistent with ICF.

Typical Components of the Dysarthria Assessment

The assessment process includes consideration of the individual's hearing and vision status. This may include hearing screening, inspection of hearing aids, and provision of an amplification device, if needed. If the individual wears corrective lenses, these should be worn during the assessment.

The assessment section below is not prescriptive—it outlines the components of a very thorough exam. Some components may not be applicable in all clinical settings.

Case History

  • Medical diagnosis and history
    • Onset and course of symptoms
    • Associated deficits (e.g., language, cognitive-communication, and swallowing, problems)
    • Medical procedures, hospitalizations, prior treatments and their outcomes
    • Other medical and rehabilitation specialty referrals and interventions and their outcomes
    • Medications and potential side effects/symptoms
  • Review of auditory, visual, motor, cognitive, language, and emotional status (if not included as part of the assessment)
  • Education, vocation, and cultural and linguistic backgrounds
  • Patient and family report
    • Awareness, observations, and perspectives
    • Person-specific communication needs
    • Impact of the presenting problem on activities and participation
  • Identification of facilitators of and barriers to communication
    • Extent to which the level of effort for speaking changes in different contexts (e.g., when fatigued, at different times of day, relative to medication schedule)
    • Adaptability in different communication contexts (e.g., in noisy environments, with distractions, with multiple communication partners, with unfamiliar listeners)

Nonspeech Examination

  • Assessment of speed, strength, range, accuracy, coordination, and steadiness of nonspeech movements and assessment of the speech subsystems using objective measures, as available. The following are typically included:
    • Completion of a cranial nerve exam (CN V, VII, IX, X, XI, XII)—to assess facial, oral, velopharyngeal, and laryngeal function and symmetry
    • Observation of facial and neck muscle tone—at rest and during nonspeech activities (Clark & Solomon, 2012)
    • Assessment of sustained vowel prolongation—to determine if there is adequate pulmonary support and sufficient laryngeal valving for phonation
    • Assessment of alternating motion rates (AMRs) and sequential motion rates (SMRs) or diadochokinetic rates—to judge speed and regularity of jaw, lip, and tongue movement and, to a lesser extent, articulatory precision (see Kent, Kent, & Rosenbek, 1987)

Speech Production

  • Vocal quality and ability to change loudness and pitch—to assess laryngeal/phonatory function (see ASHA's Practice Portal page on Voice Disorders)
  • Stress testing—2 to 4 minutes of reading or speaking aloud to assess deterioration over time (can use spontaneous conversation, reading text aloud, or counting)
  • Motor speech planning or programming—repetition of simple and complex multisyllabic words and sentences to determine if apraxia of speech (AOS) is present (see ASHA's Practice Portal page on Acquired Apraxia of Speech)

Prosody—use of variations in pitch, loudness, and duration to convey emotion, emphasis, and linguistic information (e.g., meaning, sentence type, syntactic boundaries); speech naturalness reflects prosodic adequacy

  • Recommendations for speech sampling include the following:
    • Use connected speech (reading and spontaneous speech) to observe variations in pitch, loudness, and duration.
    • Use targeted prosodic tasks, including asking and answering questions; contrastive stress tasks; and reading statements using prosodic variation to express different emotions.

Speech Intelligibility—the degree to which the listener (familiar/unfamiliar) understands the individual's speech; typically reported as a percentage of words correctly identified by a listener

  • Recommendations for speech sampling include the following:
    • Use material unknown to the listener and with low semantic predictability.
    • Include words that provide a sampling of most of the phonemes.
    • Tasks include single-word production and sentence production (recorded and later transcribed by a judge).

Comprehensibility—the degree to which the listener understands the spoken message, given other information or cues (e.g., topic, semantic context, gestures) to enhance communication; typically reported as percentage of words correctly identified by a listener

  • Materials and tasks are similar to those used to assess speech intelligibility.
  • Various cues (e.g., auditory, visual, contextual) are provided to the listener.
  • The speaker's use of comprehensibility strategies or the potential to adopt these strategies can also be assessed during these tasks.

Efficiency—the rate at which intelligible or comprehensible speech is communicated; typically reported as the number of intelligible or comprehensible words per minute

  • Sentence-level materials and tasks are similar to those used to assess speech intelligibility and comprehensibility.
  • Sentences are transcribed by a judge, and the number of correct words per minute are computed.

Other components of the assessment may include a review of the following, which may lead to further, in-depth assessment of these areas:

  • Language—assess receptive and expressive language skills in oral and written modalities to help distinguish between dysarthria and aphasia. See ASHA's Practice Portal page on Aphasia.
  • Cognitive-Communication—identify aspects of verbal or nonverbal communication that may be affected by disruptions in cognition (e.g., attention, memory, organization, executive function). See ASHA's resources on cognitive-communication.
  • Swallowing—assess swallowing function. See ASHA's Practice Portal page on Adult Dysphagia.


Assessment may result in the following outcomes:

  • Diagnosis of dysarthria and classification of dysarthria type.
  • Clinical description of the dominant auditory-perceptual speech characteristics and the severity of the disorder.
  • Presence of co-morbid conditions, including apraxia of speech, aphasia, cognitive-communication disorder, or swallowing disorder.
  • Statement of prognosis and recommendations for intervention that relate to overall communication adequacy.
  • Development of an intervention or management plan (in collaboration with patient, family, and rehabilitation team), including (a) prosthetic or surgical management or (b) augmentative and alternative communication (AAC), as appropriate. See ASHA's Practice Portal page on Augmentative and Alternative Communication.
  • Identification of relevant follow-up services, including support for individuals with dysarthria.
  • Referral to other professionals as needed (e.g., neurologist, psychologist).

Differentiating Among Dysarthria Types

Given the overlap in speech characteristics and other deficits across the dysarthrias, it may be difficult to determine dysarthria type, particularly when the underlying etiology is unknown (Fonville et al., 2008; Van der Graaff et al., 2009; Zyski & Weisiger, 1987). However, there are a number of distinguishing speech characteristics and physical findings that can be useful in making a differential diagnosis. See Distinguishing Perceptual Speech Characteristics and Physiologic Findings by Dysarthria Type.

Distinguishing Dysarthria From Apraxia of Speech

Listed below are characteristics and comparisons often used to distinguish dysarthria from apraxia of speech (AOS). Some dysarthria types (e.g., ataxic, hyperkinetic, and unilateral upper motor neuron) share some characteristics with AOS and can be difficult to distinguish (Bislick, McNeil, Spencer, Yorkston, & Kendall, 2017; Duffy, 2013).

  • Muscle weakness or spasticity are present in several dysarthria types; AOS does not present with muscle weakness or spasticity unless there is a concomitant dysarthria.
  • Several subsystems can be affected in dysarthria—unlike AOS, which is predominated by articulatory and prosodic deficits.
  • In contrast to AOS, dysarthric speech may present with more consistent error patterns and is generally not influenced by automaticity of speech production, stimulus modality, and linguistic variables (Duffy, 2013).
  • Other apraxic speech characteristics, such as a larger variety of articulatory errors and groping for articulatory postures, are typically not seen in dysarthria.
  • Poorer performance on SMRs than on AMRs in AOS may distinguish it from ataxic dysarthria (Duffy, 2013).

For more information about AOS, see ASHA's Practice Portal page on Acquired Apraxia of Speech.

Distinguishing Dysarthria From Aphasia

Aphasia affects language comprehension and expression in both spoken and written modalities; dysarthria affects only speech production.

When an individual has both dysarthria and aphasia, and verbal expression is significantly impaired, the clinician will need to determine if the problem is motor based or language based—or some combination of the two.

Intelligibility and speech naturalness can be significantly compromised by dysarthria; however, delays during speech and/or attempts by the speaker to revise content might indicate language expression problems associated with aphasia. In such cases, it may be necessary to assess written language expression as well as oral and written language comprehension to make a definitive diagnosis. If deficits are found in these modalities, it is likely that language problems are contributing to verbal expression difficulties (Duffy, 2013). For more information about aphasia, see ASHA's Practice Portal page on Aphasia.

Cultural and Linguistic Factors

When selecting screening and assessment tests, the SLP considers the influence of cultural and linguistic factors on the individual's communication style and the potential impact of impairment on function. Variations in dialect should be taken into consideration before marking phonemes in error if they were not part of the client's repertoire or dialect prior to injury or disease.

The assessment is conducted in the language(s) used by the person with dysarthria, with the use of interpretation services as necessary. See ASHA's Practice Portal pages on Collaborating With Interpreters, Transliterators, and Translators and Bilingual Service Delivery.

Appropriate accommodations and modifications must be made to the testing process to reconcile cultural and linguistic variations. Comprehensive documentation includes descriptions of these accommodations and modifications. Scores from standardized tests should be interpreted and reported with caution in these cases.

Content Disclaimer: The Practice Portal, ASHA policy documents, and guidelines contain information for use in all settings; however, members must consider all applicable local, state and federal requirements when applying the information in their specific work setting.