Psychometric properties and clinical correlates of the Frontal Behaviour Inventory in progressive supranuclear palsy: data from the PSP-NET

Neuropsychiatric symptoms, such as apathy, disinhibition and irritability, are common in Progressive Supranuclear Palsy (PSP). The Frontal Behaviour Inventory (FBI) is a useful instrument for the evaluation of behavioural disorders in neurodegenerative diseases. The main goal of the present study was to explore the psychometric properties of the FBI in PSP.OBJECTIVESNeuropsychiatric symptoms, such as apathy, disinhibition and irritability, are common in Progressive Supranuclear Palsy (PSP). The Frontal Behaviour Inventory (FBI) is a useful instrument for the evaluation of behavioural disorders in neurodegenerative diseases. The main goal of the present study was to explore the psychometric properties of the FBI in PSP.FBI was administered to the PSP-NET cohort including Italian patients diagnosed according to the Movement Disorder Society criteria. Patients underwent a clinical interview, a motor evaluation, extensive cognitive and behavioural testing.DESIGN, SETTING AND PARTICIPANTSFBI was administered to the PSP-NET cohort including Italian patients diagnosed according to the Movement Disorder Society criteria. Patients underwent a clinical interview, a motor evaluation, extensive cognitive and behavioural testing.Two hundred and eight subjects were included in this study. The internal consistency was high (Cronbach's alpha = 0.868) and no improvement of this value was noted upon removal of any item. FBI showed also good acceptability, reliability and validity. The standard error of measurement (SEM) value for FBI total score was 0.169 [SEM = SD √ (1 - Cronbach's alpha)]. Factor analysis indicated a five-factor structure: Apathy, Behavioural disorders, Impulsivity, Motor and speech frontal behaviour and Executive disorders that explained the 54.92% of the total variance. Linear regression analysis showed that global cognitive impairment significantly affects both Apathy and Motor and speech frontal behaviour factors.RESULTSTwo hundred and eight subjects were included in this study. The internal consistency was high (Cronbach's alpha = 0.868) and no improvement of this value was noted upon removal of any item. FBI showed also good acceptability, reliability and validity. The standard error of measurement (SEM) value for FBI total score was 0.169 [SEM = SD √ (1 - Cronbach's alpha)]. Factor analysis indicated a five-factor structure: Apathy, Behavioural disorders, Impulsivity, Motor and speech frontal behaviour and Executive disorders that explained the 54.