Multidimensional apathy in ALS:validation of the Dimensional Apathy Scale

AIM: Apathy is a prominent symptom of amyotrophic lateral sclerosis (ALS), but measurement is confounded by physical disability. Furthermore, it has been traditionally measured as a unidimensional symptom despite research demonstrating a multifaceted construct. The new Dimensional Apathy Scale (DAS) has been specifically designed for patients with motor disability to measure 3 neurologically based subtypes of apathy: Executive, Emotional and Initiation. We aimed to explore this behavioural symptom by examining the substructure of apathy in ALS and to determine the reliability and validity of the DAS in patients and their carers.  METHOD: Patients and carers were recruited through the national Scottish Motor Neurone Disease Register and were asked to complete the DAS, the standardised Apathy Evaluation Scale, and the Geriatric Depression Scale-Short Form. 83 patients with ALS, 75 carers and 83 sex-matched, age-matched and education-matched controls participated.  RESULTS: When compared with healthy controls, patients showed a significant increase in apathy on the Initiation subscale, and were significantly less apathetic on the Emotional subscale. Scores on the DAS patient and carer versions did not significantly differ. Internal consistency reliability, convergent and discriminant validity were found to be good for the DAS subscales. There was no association between the DAS and functional disability using the ALS Functional Rating Scale.  CONCLUSIONS: Apathy in ALS is characterised by a specific profile of increased initiation apathy and reduced emotional apathy. The DAS is a reliable and valid measure for the assessment of multidimensional apathy in ALS

Multidimensional apathy in behavioural variant frontotemporal dementia, primary progressive aphasia and Alzheimer’s disease

Apathy is prevalent in dementia, such as behavioral variant frontotemporal dementia (bvFTD), primary progressive aphasia (PPA), and Alzheimer disease (AD). As a multidimensional construct, it can be assessed and subsumed under a Dimensional Apathy Framework. A consistent apathy profile in bvFTD and PPA has yet to be established. The aim was to explore apathy profiles and awareness in bvFTD, PPA, and AD. A total of 12 patients with bvFTD, 12 patients with PPA, 28 patients with AD, and 20 matched controls, as well as their informants/carers, were recruited. All participants completed the Dimensional Apathy Scale (DAS), assessing executive, emotional, and initiation apathy subtypes, a 1-dimensional apathy measure, depression measure, and functional and cognitive screens. Apathy subtype awareness was determined through DAS informant/carer and self-rating discrepancy. Apathy profile comparison showed patients with bvFTD had significantly higher emotional apathy than patients with AD (P <.01) and significantly higher apathy over all subtypes than patients with PPA (Ps <.05). Additionally, patients with bvFTD had significantly lower awareness for emotional apathy (P <.01) when compared to patients with AD and PPA. All patient groups had significant global apathy over all subtypes compared to controls. The emergent apathy profile for bvFTD seems to be emotional apathy (indifference or emotional/affective neutrality), with lower self-awareness in this subtype. Further, lower self-awareness for executive apathy (lack of motivation for planning, organization, or attention) differentiates bvFTD from PPA. Future research should investigate the cognitive and neural correlates as well as the practical impact of apathy subtypes

The brief Dimensional Apathy Scale: A short clinical assessment of apathy

Objective: Apathy is a prominent syndrome across neurodegenerative diseases. The Dimensional Apathy Scale (DAS) assesses three apathy subtypes—executive, emotional, and initiation—and is sensitive and valid in amyotrophic lateral sclerosis (ALS), Alzheimer’s disease (AD), and Parkinson’s disease. This study describes the development of the brief DAS (b-DAS), which will enable apathy to be swiftly detected in the clinic. Method: 102 ALS and 102 AD patients’ previously collected data were used. Mokken analyses were performed on item-level data of each informant/carer-rated DAS subscale (executive, emotional, and initiation) for the initial scale reduction. Item-total correlational analyses against standard apathy (convergent validity criteria) and depression (divergent validity criteria) measures and qualitative examination of items aided final item selection. Receiver operating curve analysis determined optimal cutoffs for the reduced subscales. Results: Mokken analyses suggested unidimensionality of each DAS subscale. Three items were removed that failed to satisfy monotone homogeneity model requirements, three items were removed due to validity criteria not being met, and six items were removed due to a combination of lower item scalability and item-total correlations. Item-theme examination further reduced the b-DAS to nine items, three per subscale, with a supplemental awareness deficit assessment being added. Sensitivity- and specificity-based optimal cutoffs were calculated for each b-DAS subscale. Conclusions: This study presents the b-DAS, an informant/carer-based robust yet short multidimensional apathy instrument with good convergent and divergent validity, with recommended clinical cutoffs. The b-DAS is appropriate for use in the clinic and for research to quickly and comprehensively screen for apathy subtype impairments