A Novel Ecological Approach Reveals Early Executive Function Impairments in Huntington’s Disease

Abstract

Introduction: Impairments in executive functions are common in neurogenetic disorders such as Huntington’s disease (HD) and are thought to significantly influence the patient’s functional status. Reliable tools with higher ecological validity that can assess and predict the impact of executive dysfunction in daily-life performance are needed. This study aimed to develop and validate a novel non-immersive virtual reality task (“EcoKitchen”) created with the purpose of capturing cognitive and functional changes shown by HD carriers without clinical manifestations of the disease (Premanifest HD), in a more realistic setting. Materials and Methods: We designed a virtual reality task with three blocks of increasing executive load. The performance of three groups (Controls, CTRL; Premanifest HD individuals, HP; Early Manifest HD patients, HD) was compared in four main components of the study protocol: the EcoKitchen; a subjective (self-report) measure – “The Adults and Older Adults Functional Assessment Inventory (IAFAI)”; the “Behavioural Assessment of Dysexecutive Syndrome battery (BADS)”; and a conventional neuropsychological test battery. We also examined statistical associations between EcoKitchen and the other executive, functional and clinical measures used. Results: The HD group showed deficits in all the assessment methods used. In contrast, the HP group was only found to be impaired in the EcoKitchen task, particularly in the most cognitively demanding blocks, where they showed a higher number of errors compared to the CTRL group. Statistically significant correlations were identified between the EcoKitchen, measures of the other assessment tools, and HD clinical features. Discussion: The EcoKitchen task, developed as an ecological executive function assessment tool, was found to be sensitive to early deficits in this domain. Critically, in premanifest HD individuals, it identifies dysfunction prior to symptom onset. Further it adds a potential tool for diagnosis and management of the patients’ real-life problems.

Available Virtual Reality-Based Tools for Executive Functions: A Systematic Review

“…Júlio et al conducted research to get a comprehensive picture of the real-life executive deficits shown by Huntington's disease (HD) patients using a novel VR task – “EcoKitchen” (Júlio et al, 2016 , 2019 ). It was designed and developed to evaluate planning, multi-tasking, set-shifting, cognitive flexibility, self-monitoring, sequencing, divided attention and scanning skills.…”

“…In a first preliminary study, the authors showed that this VR-based task appeared sensitive to early deficits in both premanifest HD and manifest HD than controls, with clinical groups that showed an overall slower cognitive and motor performance and a higher number of attention errors (Júlio et al, 2016 ). In the following study, the same three groups underwent complete evaluation with EcoKitchen and traditional neuropsychological batter (e.g., Phonemic Verbal Fluency test, Semantic Verbal Fluency test, Stroop test, Symbol Digit Modalities Test, Digit Span Test, TMT and WCST) (Júlio et al, 2019 ). Manifest HD group showed deficits in all assessment measures with a statistically significant correlation between the EcoKitchen, traditional neuropsychological battery and HD clinical features.…”

The effect of impulsivity and inhibitory control deficits in the saccadic behavior of premanifest Huntington’s disease individuals

“…Finally, the fact that significant differences were absent at the level of conventional neuropsychological test results between Pre-HD and CTRL participants leads us to hypothesize that the neuropsychological test battery used, even if extensive, was not sufficiently sensitive to the subtle and earliest changes that occur in HD cognition—subtle changes synonymous of small effect sizes, might need larger samples of premanifest gene carriers for testing novel hypotheses. Also, having a set of more ecological neuropsychological tests would probably help to better distinguish between the Pre-HD and CTRL groups, as cognitive assessment methods that resemble daily-life tasks have proven to be more successful at differentiating premanifest HD individuals far from estimated disease onset and controls [95, 96].…”

Assessment of cognitive instrumental activities of daily living: a systematic review

“…In conclusion, the main benefits of virtual reality for the evaluation of IADLs include affordability, safety, efficiency, applicability to a wide range of conditions and ease of data capture and qualification [21,34].…”

“…Indeed, difficulties performing IADLs have been closely associated with deficits in executive functions, which increase the need to develop effective compensatory strategies to meet the demands of IADLs [3,18]. Deficits in executive functions are a predictor of participation and functional outcomes of various pathologies [19]; they occur in over 66% of patients having had a mild stroke [20] and predict functional outcomes at three, six, nine and twelve months in stroke patients [21,22]. EF has been found to explain 37% of the variance of functional status in individuals with mild cognitive impairment, unlike other cognitive processes [23].…”