Multidimensional apathy in ALS: validation of the Dimensional Apathy Scale

Abstract

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 three 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 MotorNeurone Disease Register and were asked to complete the DAS, the standardised Apathy Evaluation Scale, and the Geriatric Depression Scale-Short form. 83 ALS patients, 75 carers and 83 sex-age-education matched controls participated.Results: When compared to 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.Conclusion: 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.3

A Novel Assessment and Profiling of Multidimensional Apathy in Alzheimer’s Disease

“…The discriminant validity was shown to be good, where Emotional apathy was not associated with depression, which supports the distinction between these two respective concepts of emotional neutrality and emotionality previously observed [30,31].…”

“…A combination of Executive and Initiation apathy was shown to be central in AD, which was further supplemented by an apathy subtype awareness deficit. Furthermore, in the scope of previous multidimensional apathy research in amyotrophic lateral sclerosis and Parkinson's disease [30,31], these findings add to the complexities of apathy profiles and indicate a unique AD profile, further taking in to account apathy subtype awareness difficulties.…”

“…We also found no significant difference on the standardized depression measure between AD self-and informant/carer-ratings, providing further support that emotional aspects of functioning, both neutral (apathy) and negative (depression) are not prone to the awareness deficits. In the scope of previous research, amyotrophic lateral sclerosis and Parkinson's disease [30,31] have not shown apathy awareness deficits, which could suggest this is specific to dementia. Furthermore, this adds the construct of apathy subtype awareness to the emerging Dimensional Apathy framework that can be measured through discrepancy scores between self-and informant-carer ratings.…”

“…Both the carer-rated and self-rated packs contained the DAS [29,30], Apathy Evaluation Scale (AES) [19] and the Geriatric Depression Scale-Short form (GDS-15) [33,34] and the carers completed the Lawton Instrumental Activities of Daily Living (LIADL) [35].…”

“…The Dimensional Apathy Scale (DAS) [29] has been designed to assess different apathy subtypes by a subscale-based, quantitative method that has been validated in amyotrophic lateral sclerosis [30] and Parkinson's disease [31]. The DAS measures lack of motivation for planning, attention and organization (Executive apathy), indifference or emotional neutrality (Emotional apathy) and self-generation of though (Initiation apathy).…”