Impairments in knowledge of social norms in presymptomatic, prodromal, and symptomatic frontotemporal dementia

INTRODUCTION: We aimed to assess the knowledge of social norms in patients with behavioral variant frontotemporal dementia (bvFTD) with the Dutch version of the Social Norms Questionnaire (SNQ-NL). METHODS: The SNQ-NL was administered in 34 patients with bvFTD, 20 prodromal mutation carriers, 76 presymptomatic mutation carriers, and 56 controls. Group differences and correlations with other neuropsychological tests and gray matter volume were examined. RESULTS: Patients with bvFTD had lower total SNQ-NL scores and more over-adherence errors than presymptomatic mutation carriers and controls (P < 0.001). SNQ-NL performance correlated with tests for executive functioning and social cognition, and with gray matter volume in bilateral frontal and unilateral temporal regions. DISCUSSION: The SNQ-NL can identify impairments in knowledge of social norms in bvFTD, highlighting its significance in clinical diagnosis and upcoming clinical trials. The SNQ-NL currently fails to differentiate presymptomatic mutation carriers from controls; to this end, larger sample sizes from larger cohorts and longitudinal follow-up are warranted. Highlights: The Dutch version of the Social Norms Questionnaire (SNQ-NL) is able to detect impairment in social cognition in symptomatic bvFTD patients. A trend towards a lower performance in prodromal mutation carriers was found. Performance on the SNQ-NL is related to other measures of social cognition, executive functioning, and language. Lower SNQ-NL performance is related to gray matter volume loss in bilateral frontal and temporal regions. The SNQ-NL provides insight into the underlying cause of deficits in social cognition in bvFTD.