The Cambridge Questionnaire for Apathy and Impulsivity Traits (CamQUAIT): a novel assessment tool for frontotemporal lobar degeneration-related syndromes

STATE OF THE ART: Apathy and impulsivity are common in syndromes associated with frontotemporal lobar degeneration (FTLD). They are associated with high carer distress and poor patient outcomes. There are limited treatment options and progress has been hindered by a lack of appropriate outcome measures. This study aimed to develop a carer-rated questionnaire oriented to people with syndromes associated with FTLD. METHODOLOGY: Principal component and Rasch analysis were conducted on carer-, clinician- and patient-reported questionnaires and performance-based tests of behavioural change in the "Pick's Disease and Progressive Supranuclear Palsy Prevalence and Incidence" (PiPPIN) study. We identified two key components which informed subsequent item development for a novel scale which we call the Cambridge Questionnaire for Apathy and Impulsivity Traits (CamQUAIT). The resulting scale comprised two subscales assessing "motivation and support" (CamQUAIT-M) and "impulsivity and challenging behaviours" (CamQUAIT-C). An independent sample of 132 carers for people with FTLD-associated syndromes completed the CamQUAIT, along with a battery of existing measures. The CamQUAIT was reduced to 15 items following Rasch analysis. RESULTS: Both subscales showed good construct validity as assessed by high Person separation index (CamQUAIT-M = 0.9; CamQUAIT-C = 0.7) and Cronbach's alpha (CamQUAIT-M = 0.9; CamQUAIT-C = 0.8). The subscales correlated moderately with each other (r = 0.376, p < 0.001), and with existing measures of behavioural change. CONCLUSION: The CamQUAIT is a targeted measurement tool to assess apathy, impulsivity, and related behavioural change in the context of FTLD-related syndromes. The scale demonstrates good measurement properties and is sensitive to group differences, providing a suitable outcome measure to evaluate novel symptomatic treatments.