Possible demographic influences on differentiating normal from aphasic performance

To determine the psychometric validity of current language impairment, communication activity limitation, and quality of life measures for differentiating normal from chronically aphasic adults, we examined possible threats to test accuracy by the demographic variables age, educational level, and gender. A total of 18 chronically aphasic and 18 nonaphasic adults were evaluated with six measures. The results of correlational analyses indicated that, within the normal adult and aphasic adult groups, there exist significant relationships between some, but not all, demographic variables and performance on language impairment, communication activity limitation, and quality of life measures. Moreover, for certain variables, the strengths of these relationships differ significantly between normal and aphasic groups. Thus, adjustments in test scores or norms may be necessary to diagnose the presence or absence of aphasia. Otherwise, the tests' ability to differentiate between normal and aphasic adults may be compromised.

Readers will be able to: (1) explain the relationship between test accuracy and psychometric validity; (2) state the direction of significant relationships (i.e., positive or negative) among demographic variables and test performance, within normal and aphasic adult groups; (3) explain necessary considerations in the adjustment of general test norms or scores based on a particular subject's age, education, or gender.