Aphasia Severity Scale

The progressive aphasia severity scale (PASS) is a clinical instrument used to rate presence and severity of impairment in specific domains of speech and language in patients with PPA (Mesulam et al., 2009; Sapolsky, Domoto-Reilly, & Dickerson, 2014). The clinician uses his or her best clinical judgment to make ratings on a 5-point scale: normal (0) to questionable/very mild (0.5), mild (1.0), moderate (2.0), or severe (3.0) impairment. First, a baseline profile is established; then, follow-up assessments at periodic intervals of 6-12 months are completed. The scores of the PASS are meant to reflect the patient’s current level of functioning compared to the baseline, and therefore, detect any decline in abilities attributable to PPA. The test includes 10 discrete domains of
In order to gather quantitative information, a comprehensive language assessment is administered along with the patient interview. Tasks used in the PASS assessment are adapted from the Boston Diagnostic Aphasia Examination (BDAE) and Western Aphasia Battery (WAB). The PASS is a longitudinal assessment; therefore, the same test should be used at each evaluation to identify changes over time (Mesulam et al., 2009; Nickels et al., 2011; Sapolsky et al., 2014). Research has shown that the use of performance-based measures, such as the BDAE and the WAB fail to adequately gather information regarding the patient’s difficulty in everyday life. Whereas ratings of symptom severity according to clinical judgment provide a more accurate representation of the patient’s disease (i.e., PPA) (Mesulam et al., 2009; Sapolsky et al., 2014). The PASS differs from both the BDAE and WAB in terms of content, administrative instructions, and scoring