Cross-Sectional and Longitudinal Assessment of Behavior in Primary Progressive Apraxia of Speech and Agrammatic Aphasia

Introduction: Progressive agrammatic aphasia (PAA) can be associated with abnormal behaviors; however, it is unknown whether behaviors occur and/or are different in patients with primary progressive apraxia of speech (PPAOS). We aimed to compare baseline and longitudinal behavioral symptomatology between PPAOS, patients with PAA, and patients with both apraxia of speech and PAA (AOS-PAA). Methods: We recruited 89 patients for this study, 40 with PPAOS, 11 with PAA, and 38 with AOS-PAA. Behavioral disturbances were evaluated using the frontal behavior inventory (FBI) which was also split into negative behaviors and disinhibition, and the 20-item behavioral assessment scale (20-BAS). Data analysis was performed using linear regression and linear mixed models. Results: Of the 89 patients in the study, 54% were women and the mean age at onset was 68 years. All patients, regardless of diagnosis, endorsed at least one symptom on the FBI at baseline, most frequently verbal apraxia (100%), logopenia (95.6%), irritability (55.9%), and apathy (42.6%). On the 20-BAS, 47.6% of the patients endorsed at least one symptom, most commonly "crying more easily"(19.5%) and personality change (18.3%). PPAOS was the least behaviorally affected group, with differences between PPAOS and AOS-PAA mainly driven by negative behaviors as opposed to disinhibition for PPAOS and PAA. The behavioral metrics showed average sensitivity and specificity to distinguish between groups. Behavioral disturbances worsened over time although rate of behavioral change across groups was similar. Conclusion: Behavioral disturbances are more common and severe in patients with agrammatic aphasia with or without AOS compared to patients with isolated apraxia of speech.