Aphasia is an acquired neurogenic language disorder resulting from an injury to the brain, most typically the left hemisphere, that affects all language modalities. Aphasia is not a single disorder, but instead is a family of disorders that involve varying degrees of impairment in four primary areas:
- spoken language expression
- spoken language comprehension,
- written expression, and
- reading comprehension.
A person with aphasia often has relatively intact nonlinguistic cognitive skills, such as memory and executive function skills, although these and other cognitive deficits may co-occur with aphasia. Sensory deficits such as auditory and visual agnosia and visual field deficits (e.g., hemianopia or visual field cuts) may also be present.
Because categorizing aphasia subtypes can be difficult, there is debate over the terminology used to classify aphasia. While no single classification system is completely adequate, some common classifications of aphasia are based on the location of brain damage or the patterns of impaired language abilities in fluency of verbal expression, auditory comprehension, repetition, and word retrieval. Sometimes the terms motor aphasia and sensory aphasia (or nonfluent and fluent aphasia) are used. See the common classifications of aphasia adapted from Aphasiology: Disorders and Clinical Practice (Davis, 2007).
It should be noted that a person's symptoms may not fit neatly into a single aphasia type. Further, the initial presenting symptoms can change with recovery, and consequently, the classification that fits most accurately may shift. This is particularly true as a person's communication improves. In addition, symptoms can co-occur with other speech and language impairments such as dysarthria and/or apraxia of speech, which can complicate assessment and treatment.
The outcome of aphasia is difficult to predict given the wide variability of symptoms. Aphasia outcome varies significantly from person to person, depending upon the lesion location and the severity of the brain insult. The most predictive indicator of long-term recovery is initial aphasia severity, along with lesion site and size (Plowman, Hentz, & Ellis, 2011). Other factors that are often considered regarding prognosis include the person's age, gender, education level, and other comorbidities. When examined more closely, however, these factors do not appear to be strong predictors of the extent of recovery.
Incidence and Prevalence
The "incidence" of aphasia refers to the number of new cases identified in a specified time period. It is estimated that there are 80,000 new cases of aphasia per year in the United States (National Stroke Association, 2008).
"Prevalence" of aphasia refers to the number of people who are living with aphasia in a given time period. The National Institute of Neurological Disorders and Stroke (NINDS) estimates that approximately 1 million people, or 1 in 250 in the United States today, suffer from aphasia (NINDS, n.d.).
Fifteen percent of individuals under the age of 65 experience aphasia; this percentage increases to 43% for individuals 85 years of age and older (Engelter et al., 2006).
No significant differences have been found in the incidence of aphasia in men and women. However, some data suggest differences may exist by type and severity of aphasia. For example, Wernicke's and global aphasia occur more commonly in women and Broca's aphasia occurs more commonly in men (Hier, Yoon, Mohr, & Price, 1994; National Aphasia Association, 2011).
Signs and Symptoms
Aphasia symptoms vary across individuals, with some of the variation being related to the neural regions that are damaged and to the extent of that damage. Signs and symptoms may or may not be present in individuals with aphasia and may vary in severity and level of disruption to communication. Signs and symptoms may also vary depending on the speaking situation. For example, a person may need to pause frequently to find words during a conversation that requires a higher level of complexity and precision, but then may have no apparent difficulties when exchanging small talk. Examples of common signs and symptoms of aphasia are listed below.
Common verbal expression impairments include
- difficulty finding words (anomia)
- speaking with effort or haltingly
- speaking in single words (e.g., names of objects)
- speaking in short, fragmented phrases
- omitting smaller words like "the," "of," and "was" (telegraphic speech)
- putting words in the wrong order
- substituting sounds and/or words (e.g., bed is called "table" or dishwasher a "wishdasher")
- making up words (e.g., jargon)
- fluently stringing together nonsense words and real words, but leaving out or including an insufficient amount of relevant content.
Common auditory comprehension impairments include
- difficulty understanding spoken utterances
- providing unreliable answer to "yes/no" questions
- failing to understanding complex grammar (e.g., The dog was chased by the cat.)
- requiring extra time to understand spoken messages (e.g., like translating a foreign language)
- finding it very hard to follow fast speech (e.g., radio or television news)
- misinterpreting subtleties of language (e.g., takes the literal meaning of figurative speech such as "It's raining cats and dogs.")
- lacking awareness of errors.
Very often, a person with aphasia experiences both expressive and receptive difficulties, but each to varying degrees. In addition, the person with aphasia may have similar (parallel) difficulties in written expression and reading comprehension.
Common reading comprehension impairments include
- difficulty comprehending written material
- difficulty recognizing some words by sight
- inability to sound out words
- substituting associated words for a word
- difficulty reading noncontent words (e.g., function words such as to, from, the).
Common written language impairments include
- difficulty writing or copying letters, words, and sentences
- writing single words only
- substituting incorrect letters or words
- spelling or writing nonsense syllables or words
- writing run-on sentences that don't make sense
- writing sentences with incorrect grammar.
Aphasia is caused by damage to the language centers of the brain. In most people, these language centers are located in the left hemisphere, but aphasia can also occur as a result of damage to the right hemisphere; this is often referred to as crossed aphasia to denote that the right hemisphere is language dominant in these individuals. Common causes of aphasia are
- ischemic: blockage that disrupts blood flow to a region of the brain
- hemorrhagic: a ruptured blood vessel that damages surrounding brain tissue
- traumatic brain injury
- brain tumors
- brain surgery
- brain infections
- other neurological diseases (e.g., dementia).
Stroke is the most common cause of aphasia. According to the National Aphasia Association (2011), about 25% to 40% of stroke survivors experience aphasia. Approximately 35%-40% of adults admitted to an acute care hospital with a diagnosis of stroke are diagnosed with aphasia by the time they are discharged (Dickey et al., 2010; Pedersen, Jorgensen, Raaschou, & Olsen, 1995).
Roles and Responsibilities
Speech-language pathologists (SLPs) play a central role in the screening, assessment, diagnosis, and treatment of persons with aphasia. The professional roles and activities in speech-language pathology include clinical/educational services (diagnosis, assessment, planning, and treatment), prevention and advocacy, and education, administration, and research. See ASHA's Scope of Practice in Speech-Language Pathology.
Appropriate roles for SLPs include, but are not limited to,
- providing prevention information to individuals and groups known to be at risk for aphasia
- educating other professionals on the needs of persons with aphasia and the role of SLPs in diagnosing and managing aphasia
- screening individuals who present with language and communication difficulties; determining the need for further assessment and/or referral for other services
- conducting a culturally and linguistically relevant comprehensive assessment of language and communication
- diagnosing the presence or absence of aphasia
- referring to other professionals to rule out other conditions and to facilitate access to comprehensive services
- developing treatment plans, providing treatment, documenting progress, and determining appropriate dismissal criteria
- counseling persons with aphasia and their families regarding communication-related issues and providing education aimed at preventing further complications relating to aphasia
- consulting and collaborating with other professionals, family members, 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 aphasia and helping advance the knowledge base related to the nature and treatment of aphasia
- advocating for individuals with aphasia and their families at the local, state, and national levels.
As indicated in the Code of Ethics (ASHA, 2010), SLPs who serve this population should be specifically educated and appropriately trained to do so.
See the Assessment section of the aphasia evidence map for pertinent scientific evidence, expert opinion and client/caregiver perspective.
Screening does not provide a detailed description of the severity and characteristics of aphasia, but rather is a procedure for identifying the need for further assessment. Screening is an invaluable tool in the appropriate referral of persons with aphasia to speech-language pathology services and is an important first step in determining the need for treatment. It is conducted in the language(s) used by the person, and with sensitivity to cultural and linguistic diversity.
Screenings are completed by the SLP or other professional. Standardized and nonstandardized methods are used to screen oral motor functions, speech production skills, comprehension and production of spoken and written language, and cognitive aspects of communication. Screening typically focuses on body structures/functions, but may also address activities/participation and contextual factors affecting communication (see International Classification of Functioning, Disability and Health [ICF] framework proposed by the World Health Organization [WHO], 2001).
Screening may result in recommendations for rescreening; comprehensive speech, language, swallowing, or cognitive-communication assessments; or referral for other examinations or services.
Individuals identified with aphasia through screening are referred to an SLP for a more comprehensive assessment of language and communication.
Assessment is conducted to identify and describe
- underlying strengths and deficits related to spoken and written language that affect communication performance
- effects of the language disorder on the individual's activities and participation in ideal settings, everyday contexts, and employment settings
- contextual factors that serve as barriers to or facilitators of successful communication and participation for individuals with spoken and written language disorders
- the impact on quality of life for the individual and the impact on his or her family.
Assessment may result in
- diagnosis of a language disorder
- description of the characteristics and severity of the language disorder
- prognosis for change (in the individual or relevant contexts)
- recommendations for intervention and support
- identification of the effectiveness of intervention and supports
- referral for other assessments or services.
Prior to assessment, consider the influence of cultural and linguistic factors on the individual's communication style and discuss the potential impact of the impairment on quality of life and participation in daily activities with the person with aphasia, their family, and the treatment team in order to customize the assessment. In addition, evaluate sensory functions to identify deficits (e.g., auditory and visual acuity deficits, auditory and visual agnosia, and visual field cuts) that can potentially impede assessment and treatment procedures (Murray & Chapey, 2001). Also consider cognitive functions (e.g., executive function) prior to assessment.
A comprehensive assessment is sensitive to cultural and linguistic diversity and addresses the components within the WHO framework (see ASHA's Scope of Practice in Speech-Language Pathology), including body structures/functions, activities/participation, and contextual factors. Assessment should occur in the language(s) used by the person with aphasia.
Assessment can be static (i.e., using procedures designed to describe current levels of functioning within relevant domains) and/or dynamic (i.e., ongoing process using hypothesis-testing procedures to identify potentially successful intervention and support procedures). Assessment typically includes
- relevant case history, including medical status, education, occupation, and socioeconomic, cultural, and linguistic backgrounds
- review of auditory, visual, motor, cognitive, and emotional status
- standardized and nonstandardized methods, selected with consideration of ecological validity:
- client's report of areas of concern (listening, speaking, reading, writing), contexts of concern (e.g., social interactions, work activities) and language(s) used in those contexts, and goals and preferences;
- administration of standardized assessment tools and/or nonstandardized sampling or observational methods to assess and describe the individual's knowledge and skills in the areas of language form (phonology and alphabetic symbols, morphology and orthographic patterns, and syntax), content (lexicon and semantics), and use (pragmatics) across spoken and written modalities;
- analysis of natural communication samples gathered in modalities (listening, speaking, reading, or writing) and specific contexts (social, educational, or vocational) identified as problematic;
- assessment of oral, speech, and motor (e.g., hemiparesis, limb apraxia, apraxia of speech) function;
- identification of contextual barriers and facilitators and potential for effective compensatory techniques and strategies, including the use of augmentative and alternative communication (AAC)
- follow-up services to monitor spoken and written language status and ensure appropriate intervention and support in individuals with identified language disorders.
A number of valid and reliable aphasia screening tools and comprehensive assessment batteries are available to assist SLPs. These measures may be helpful in assessing basic communication difficulties or may provide a more detailed description of the type and severity of aphasia.
Comprehensive Standardized Test Battery Versus Nonstandardized Testing
Assessment of individuals with aphasia is completed in a number of ways and incorporates a range of assessment measures. In some cases, an entire standardized test battery is administered. In other cases, the clinician may give selected subtests from standardized test batteries, recognizing the impact on the psychometric properties when using subtests in this manner. This impact includes understanding that when tools are not administered according to standardized procedures, scores cannot be reported; only subjective descriptions of a person's functioning can be made. In other cases, nonstandardized tools developed by the clinician are used to probe aspects of speech, language, and cognition. The decision to use standardized or nonstandardized assessment procedures is determined by the clinician based upon a variety of factors, including the needs of the person with aphasia, the complexity of impairment, payer rules, facility policy, and other considerations.
See the Treatment section of the aphasia evidence map for pertinent scientific evidence, expert opinion and client/caregiver perspective.
Aphasia treatment is individualized to address the specific areas of need identified during assessment as well as the specific goals identified by the person with aphasia and his or her family. Additionally, treatment occurs in the language(s) used by the person with aphasia either by a bilingual SLP or with the use of trained interpreters, when necessary. In general, the aim of aphasia treatment includes
- restoring language abilities by addressing all impaired communication modalities and focusing on training in those areas in which a person makes errors
- strengthening intact modalities and behaviors to support and augment communication
- compensating for language impairments by teaching strategies and by incorporating augmentative and alternative methods of communication if they help to improve communication
- training family and caregivers to effectively communicate with persons with aphasia using communication supports and strategies, in order to maximize communication competence
- facilitating generalization of skills and strategies in all communicative contexts
- educating persons with aphasia, their families, caregivers, and other significant persons about the nature of spoken and/or written language disorders, the course of treatment, and prognosis for recovery.
Because of the complexity and nature of aphasia, and based on the individual's language profile and values, interventions vary. There are many ways to organize treatment options, including by aphasia type or by primary signs and symptoms. However, since most individuals with aphasia present with a variety of communication deficits and bring different backgrounds and unique needs to the treatment situation, treatments here are organized using the framework proposed in the WHO's ICF framework (2001).
This framework considers two overarching components: health conditions and contextual factors. The health conditions component is most relevant to the treatment descriptions below, while the contextual factors must be considered for all patients throughout the treatment process. Health conditions include body functions and structures and activity and participation.
Copyright 2008 by Aphasia Institute. Adapted with permission.
In the section below, some of the aphasia treatments described directly address body function impairments (e.g., difficulty formulating syntactically correct sentences, finding words, comprehending words or sentences), while others focus on communication activity and participation (e.g., working directly on functional tasks or situations in everyday activities such as answering the phone, completing paperwork, or ordering food). Regardless of the approach used, the ultimate goal of aphasia treatment is to maximize the individual's quality of life and communication success, using whichever approach or combination of approaches meets the needs and values of that individual.
The following are brief descriptions of both general and specific treatments for persons with aphasia. It is important to note that while the interventions below are categorized by a specific ICF domain (e.g., impairment-based treatment), the outcomes of treatment may extend across domains (Simmons-Mackie & Kagan, 2007). Where available, links to evidence and expert opinion regarding the intervention are provided. This list is not exhaustive nor does inclusion of any specific treatment approach imply endorsement from ASHA.
A treatment approach that addresses all communication modalities (spoken, written, and gestures) and focuses on training those areas in which a person makes errors.
Treatment involving the use of software programs targeting various language modalities.
Constraint Induced Language Therapy (CILT)
Intensive treatment approach focused on increasing verbal output. In contrast to many other approaches, CILT discourages the use of compensatory communication strategies, such as gestures or writing.
Melodic Intonation Therapy (MIT)
Treatment using intonation patterns (melody, rhythm, and stress) to increase the length of phrases and sentences. Reliance on intonation is gradually decreased over time. MIT targets improvement in spoken language expression.
Treatment designed to improve decoding and comprehension of written language.
Treatments designed to improve the grammatical structure of utterances, including
Treatment of Underlying Forms
An approach, grounded in linguistic theory, designed to improve sentence production for people with agrammatism that starts with training more complex sentence structures.
Verb Network Strengthening Treatment
A verb treatment approach designed to improve word retrieval in simple active sentences. Verbs are trained with pairs of related nouns to improve sentence production.
Chaining (Forward and Reverse)—an approach that breaks tasks/words/sentences into small parts and teaches the beginning (or end) part first.
Sentence Production Program for Aphasia—a prescribed treatment program designed to aid the production of specific sentence types.
Word Finding Treatment
Treatments designed to improve word finding in spontaneous utterances, including
Word Retrieval Cueing Strategies (semantic and cueing verbs)—an approach that provides additional information, such as the beginning sound of a word or contextual cues, to prompt word recall.
Gestural Facilitation of Naming—an approach that uses gestural interventions to facilitate verbalization.
Response Elaboration Training—a treatment approach designed to improve word finding and increase the number of content words used by a person with aphasia. The clinician elaborates on the person with aphasia's utterances to improve conversational abilities.
Semantic Feature Analysis Treatment—a word retrieval treatment where the person with aphasia identies important semantic features of a target word (e.g., building, books, quiet for "library"); this is thought to activate the semantic network and possibly aid in retrieval of nontargeted but related words.
An intervention designed to improve expression via written language.
Treatment approaches focusing on the use of effective and efficient communication strategies via nonverbal and alternative means, including
Augmentative and Alternative Communication (AAC)—treatment involving the use of augmentative aids, such as picture and symbol communication boards and electronic devices, to help individuals with aphasia express themselves.
Visual Action Therapy—treatment used with individuals with global aphasia. This nonvocal approach trains persons with aphasia to use hand gestures to indicate specific items.
Promoting Aphasics' Communication Effectiveness (PACE)—treatment designed to improve conversational skills using any modality to communicate messages. Both the person with aphasia and the clinician take turns as message sender or receiver, promoting active participation from the person with aphasia.
Oral Reading for Language in Aphasia (ORLA)—treatment using auditory, visual, and written cues to assist the person with aphasia in reading sentences aloud.
Treatment approaches engaging communication partners to facilitate improved communication in persons with aphasia, including
Conversational Coaching—treatment designed to improve communication between the person with aphasia and primary communication partners. The SLP serves as the "coach" for both partners.
Supported Communication Intervention (SCI)—an approach to aphasia rehabilitation that emphasizes the need for multimodal communication, partner training, and opportunities for social interaction. The three essential elements of SCI are incorporating augmentative and alternative communication, training communication partners, and promoting social communication, including participation in an aphasia group.
Social and Life Participation Effectiveness—an approach that focuses on the real-life goals of the person with aphasia, considering what the person can do with and without support. Intervention may also focus on others affected by aphasia, such as family members. Learn more.
Treatment designed to address social communication deficits, such as appropriate word choice, nonverbal communication, and understanding the rules of conversation.
Treatment approach in which communication skills are addressed in natural, relevant situations where the person with aphasia takes on the role of instructor to "novices" during conversations about topics of interest to the person with aphasia. The relationship allows both parties to demonstrate and reinforce communication strategies.
Treatment approach in which the clinician and person with aphasia construct a monologue or dialogue that is practiced intensely so that the person with aphasia can communicate about a topic of interest to them.
See the service delivery section of the aphasia evidence map for pertinent scientific evidence, expert opinion and client/caregiver perspective.
In addition to determining the type of speech and language treatment that is optimal for the person with aphasia, consider other service delivery variables that may have an impact on treatment outcomes such as format, provider, dosage, and timing.
Format refers to the structure of the treatment session (e.g., group vs. individual) provided to the person with aphasia.
Provider refers to the person providing the treatment (e.g., SLP, trained volunteer, caregiver).
Dosage refers to the frequency, intensity, and duration of service.
Timing refers to the timing of rehabilitation relative to the onset of aphasia.
Setting refers to the location of treatment (e.g., home, community-based).
In addition to the service delivery variables mentioned above, it is important to consider a person's language needs when selecting the language of intervention. Damage to the language center of the brain in bilingual individuals may produce aphasia across languages. Recovery of language may vary depending on the type of aphasia, how languages were acquired-simultaneously or sequentially-and the degree of proficiency and demands for the use of each language.
The goal of intervention might not be a full recovery of all language(s) used. For example, consider the patient/client with severe global aphasia who spoke English at work and Spanish at home and in the community. Return to work may not be feasible. English might be incorporated into treatment at a minimum; however, Spanish might be the primary focus to return the person to daily activities. It is essential to consider the linguistic demands on the patient/client.
Questions to consider when treating bilingual individuals with aphasia include the following:
- How many languages does the person speak?
- At what point did he or she learn English or a secondary language?
- When and with whom does he or she use each language? For example, what language(s) are spoken at work, at home, and with family or friends?
- What is the prognosis? How will that impact language(s) that are needed to communicate?
In addition to considering these questions, clinicians may need to consult with another professional, such as a bilingual SLP, a cultural/language broker (a person trained to help the clinician understand the person's cultural and linguistic background to optimize treatment), and/or an interpreter. An SLP will need to determine the language of treatment and its impact on cross-language generalization (i.e., improvement in the nontreated language). The language of intervention must involve the language that the person uses in the home. Demands for services in additional languages will depend on the person's ability to return to premorbid levels of functioning.
In the United States, Title VI of the Civil Rights Act of 1964 (Title VI of the Civil Rights Act, 42 U.S.C §§ 2000 et seq.) ensures equal access to services regardless of language spoken. Therefore, health care organizations are required to seek the assistance of an interpreter for provision of service when there is not a client-clinician language match.
Executive Order 13166, issued by President Clinton on August 11, 2000, clarifies that all federal agencies shall develop and implement a system by which persons with limited English proficiency (LEP) can access services and shall ensure that persons with LEP have the opportunity to provide input to federally funded agencies (Moxley, 2002). Federal agencies that fail to meet these guidelines are at risk of facing a number of potential consequences, including losing federal funding if they are found to be discriminatory in practice (Limited English Proficiency, 2013).
Views of the natural aging process and acceptance of disability vary by culture. Cultural views and preferences may not be consistent with medical approaches typically used in the U.S. health care system. It is essential that the clinician demonstrate sensitivity to family wishes when sharing potential treatment recommendations and outcomes. Clinical interactions should be approached with cultural humility.
Note: This section is under construction and will be developed in full detail based on the work of ASHA's Cultural Competence Practice Portal team.
Organizations and Related Content
Bhogal, S. K., Teasell, R., & Speechley, M. (2003). Intensity of aphasia therapy, impact on recovery. Stroke, 34, 987-993.
Brady, M. C., Kelly, H., Godwin, J, & Enderby, P. (2012). Speech and language therapy for aphasia following stroke. Cochrane Database of Systematic Reviews, 5, CD000425.
Cherney, L., Patterson, J., & Raymer, A. (2011). Intensity of aphasia therapy: Evidence and efficacy. Current Neurology and Neuroscience Reports, 11, 560-569.
Cherney, L., Patterson, J., Raymer, A., Frymark, T., & Schooling, T. (2010). Updated evidence-based systematic review: Effects of intensity of treatment and constraint-induced language therapy for individuals with stroke-induced aphasia. ASHA's National Center for Evidence-Based Practice in Communication Disorders. Rockville, MD: American Speech-Language-Hearing Association.
Civil Rights Act of 1964 § 7, 42 U.S.C. § 2000e et seq (1964).
Davis, G. A. (2007). Aphasiology: Disorders and clinical practice (2nd ed.). Needham Heights, MA: Allyn & Bacon.
Dickey, L., Kagan, A., Lindsay, M. P., Fang, J., Rowland, A., & Black, S. (2010). Incidence and profile of inpatient stroke-induced aphasia in Ontario, Canada. Archives of Physical Medicine and Rehabilitation, 91, 196-202.
Engelter, S. T., Gostynski, M., Papa, S., Maya, F., Claudia, B., Vladeta, A.G., … Phillipe, A. L. (2006). Epidemiology of aphasia attributable to first ischemic stroke: Incidence, severity, fluency, etiology, and thrombolysis. Stroke, 37, 1379-1384
Faroqui-Shah, Y., Frymark, T., Mullen, R., & Wang, B. (2010). Effect of treatment for bilingual individuals with aphasia: A systematic review of the evidence. Journal of Neurolinguistics, 23(4), 319-341.
Framework for Outcome Measurement (FROM). Aphasia Institute. Toronto, Ontario, Canada. OR Kagan, A., Simmons-Mackie, N., Rowland, A., Huijbregts, M., Shumway, E., McEwen, S., … & Sharp, S. (2008). Counting what counts: A framework for capturing real-life outcomes of aphasia intervention. Aphasiaology, 22(3), 259-280.
Hier, D. B., Yoon, W. B., Mohr, J. P. & Price, T. R. (1994). Gender and aphasia in the stroke bank.
Brain and Language, 47 , 155-167.
Hurkmans, J., de Bruijn, M., Boonstra, A., Jonkers, R., Bastiaanse, R., Arendzen, H., & Reinders-Messelink, H. (2012). Music in the treatment of neurological language and speech disorders: A systematic review. Aphasiology, 26, 1-19.
Intercollegiate Stroke Working Party. (2012). National clinical guidelines for stroke (3rd ed.). London, United Kingdom: Royal College of Physicians.
Limited English Proficiency - A Federal Interagency Website (2013). Available from www.lep.gov
Lingraphica (n.d.). Who gets aphasia? Retrieved from http://www.aphasia.com/about-aphasia/who-gets-aphasia
Moxley, A. (2002, November 05). Make your grant count: Igniting change through research. The ASHA Leader.
Murray, L. L., & Chapey, R. (2001). Assessment of language disorders in adults. In R. Chapey (Ed.), Language intervention strategies in aphasia and related neurogenic communication disorders (pp. 55-126). Philadelphia, PA: Lippincott, Williams & Wilkins.
Mesulam, M. (2001). Primary progressive aphasia. Annals of Neurology, 49, 425-432.
National Aphasia Association (2011). www.aphasia.org
National Institute of Neurological Disorders and Stroke. (n.d.). NINDS aphasia information page. Retrieved from http://www.ninds.nih.gov/disorders/aphasia/aphasia.htm
National Stroke Association. (2008). http://www.stroke.org
National Stroke Foundation (2010). Clinical guidelines for acute stroke management 2010. Melbourne, Australia: Author.
Stroke Foundation of New Zealand and New Zealand Guidelines Group (2010). New Zealand Clinical Guidelines for Stroke Management 2010.Wellington, New Zealand: Stroke Foundation of New Zealand.
Pedersen, P. M., Jorgensen, H. S., Raaschou, H. O., & Olsen, T. S. (1995). Aphasia in acute stroke: Incidence, determinants, and recovery. Annals of Neurology, 38, 659-666.
Plowman, E., Hentz, B., & Ellis, C. (2012). Post-stroke aphasia prognosis: A review of patient-related and stroke-related factors. Journal of Evaluation in Clinical Practice, 18, 689-694.
Rogers, M. (2004). Aphasia, primary progressive. In R. D. Kent (Ed.), The MIT encyclopedia of communication disorders (pp. 245-249). Cambridge, MA: MIT Press.
Taylor-Goh, S. (Ed.) (2005). Royal College of Speech and Language Therapists Clinical Guidelines: 5.12 Aphasia. Bicester, United Kingdom: Speechmark.
Simmons-Mackie, N., & Kagan, A. (2007). Application of the ICF in aphasia. Seminars in Speech and Language, 28, 244-253.
Simmons-Mackie, N., Raymer, A., Armstrong, E., Holland, A., & Cherney, L. R. (2010). Communication partner training in aphasia: A systematic review. Archives of Physical Medicine and Rehabilitation, 91, 1814-1837.
Catalan Agency for Health Technology Assessment and Research (2007). Stroke: Clinical practice guideline (2nd ed.). Barcelona, Spain: Author.
Teasell, R. W., Foley, N. C., & Salter, K. (2011). Evidence-based review of stroke rehabilitation (14th ed.). Retrieved from www.ebrsr.com
Management of Stroke Rehabilitation Working Group (2010). VA/DOD clinical practice guideline for the management of stroke rehabilitation. Journal of Rehabilitation Research & Development, 47(9), 1-43.
World Health Organization. (2001). International classification of functioning, disability and health. Geneva, Switzerland: Author.