The ALS-FTD-Q: a new screening tool for behavioural disturbances in ALS

Objective: The assessment of behavioral disturbances in amyotrophic lateral sclerosis (ALS) is important because of the overlap with the behavioral variant of frontotemporal dementia (ALS-bvFTD). Motor symptoms and dysarthria are not taken into account in currently used behavioral questionnaires. We examined the clinimetric properties of a new behavioral questionnaire for patients with ALS (Amyotrophic Lateral Sclerosis-Frontotemporal Dementia-Questionnaire [ALS-FTD-Q]).
Methods: In addition to other clinimetric properties, we examined reliability, clinical validity, and construct validity of the ALS-FTD-Q, using data from patients with ALS (n = 103), ALS-bvFTD (n = 10), bvFTD (n = 25), muscle disease control subjects (n = 39), and control subjects (n = 31). Construct validity of the ALS-FTD-Q was assessed using the Frontal Systems Behavior scale (FrSBe), Frontal Behavioral Inventory (FBI), Hospital Anxiety and Depression Scale, ALS Functional Rating Scale-Revised, Frontal Assessment Battery, Mini-Mental State Examination, and a fluency index. In addition, the point prevalence of behavioral disturbances according to the ALS-FTD-Q was compared with those obtained with the FrSBe and FBI.
Results: The internal consistency of the ALS-FTD-Q was good (Cronbach [alpha] = 0.92). The ALS-FTD-Q showed construct validity because it correlated highly with other behavioral measures (r = 0.80 and 0.79), moderately with measures of frontal functions and global cognitive functioning (r = 0.37; r = 0.32), and poorly with anxiety/depression and motor impairment (r = 0.18 for both). The ALS-FTD-Q discriminated between patients with ALS-bvFTD, patients with ALS, and control subjects. The point prevalence of behavioral disturbances in patients with ALS measured with the ALS-FTD-Q was lower than that for the FrSBe and FBI.
Conclusion: The ALS-FTD-Q is a feasible and clinimetrically validated instrument for the screening of behavioral disturbances in ALS.