Aphasia Evidence Map for pertinent scientific evidence, expert opinion, and client/caregiver perspective.
Aphasia is an acquired neurogenic language disorder resulting from an injury to the brain—most typically, the left hemisphere. Aphasia involves varying degrees of impairment in four primary areas:
- Spoken language expression
- Spoken language comprehension
- Written expression
- Reading comprehension
Depending on an individual’s unique set of symptoms, impairments may result in loss of ability to use communication as a tool for life participation (Threats & Worrall, 2004).
A person with aphasia often has relatively intact nonlinguistic cognitive skills, such as memory and executive function, although these and other cognitive deficits may co-occur with aphasia.
A number of classification systems are used to describe the various presentations of aphasia. One of the most common is based on the pattern of impaired language abilities. Using this system, aphasia is categorized as either nonfluent or fluent, based on characteristics of spoken language expression (Davis, 2007; Goodglass & Kaplan, 1972). See ASHA’s resource titled
Classification of Aphasia [PDF] for descriptions of aphasia types using this classification system.
A person’s symptoms may not fit neatly into a single aphasia type, and classification may change over time as communication improves with recovery. In addition, symptoms can co-occur with other speech and language impairments such as dysarthria and apraxia of speech, which can complicate classification.
The outcome of aphasia varies significantly from person to person. The most predictive indicator of long-term recovery is initial aphasia severity, along with lesion site and size (Plowman, Hentz, & Ellis, 2012). Other predictors of long-term recovery include age, gender, education level, and other comorbidities (Laska, Hellblom, Murray, Kahan, & Von, 2001; Payabvash et al., 2010; Pedersen, Vinter, & Olsen, 2004).
Factors that may negatively affect improvement include poststroke depression (Berg, Palomäki H., Lehtihalmes M., Lönnqvist J., & Kaste, 2003) and social isolation after onset of aphasia (Hilari & Northcott, 2006; Vickers, 2010).