Dual tasking paradigm in clinical stages of early Alzheimer’s disease

Abstract

AbstractBackgroundIn Alzheimer’s disease (AD) both motor and cognitive domains are impaired [1‐2]. However, these domains are usually assessed independently, even when performing dual‐task (DT) paradigms, the cognitive‐motor interaction (CMI) is not taken into account which may lead to misinterpretation of the patient’s global state. To date, there are no precise markers to neither detect subtle signs of pre‐clinical neurodegeneration nor accurately monitor disease progression.MethodWe have evaluated the motor and cognitive components of a DT paradigm concurrently (Figure 1). 50 participants, aged 60 to 80 years, were included in the study, distributed across four cohorts corresponding to progressive clinical stages of early AD [3]: 1) amyloid negative, cognitively healthy participants (control group), 2) amyloid positive pre‐symptomatic AD, 3) Mild Cognitive Impairment (MCI) due to AD and 4) mild AD. Two inertial measurement units (IMUs) (Physilog, GaitUp S.A.) were attached to each foot to measure gait parameters and a small microphone (Wireless GO, RØDE) was attached to the shirt to record counting. Both timing and gait features were extracted from raw data, however only conventional features, correct response rate (CRR) and gait speed, were considered for this abstract and were used to evaluate the CMI based on Plummer’s classification system [5]. Moreover two‐way ANOVA was carried out to evaluate the effect of cohort and cognitive load conditions on the CMI.ResultOur results show that there is a significant drop in performance at both the cognitive and motor tasks while performing DT and that this drop is more pronounced as we move toward stages of greater cognitive impairment and as we increase the cognitive load of the task (Figure 2). Moreover, CMI shows a cognitive‐priority trade‐off in all cohorts (better/similar counting while slower walking), but movement toward mutual interference effect (worst counting and slower walking) when increasing cognitive load and state of cognitive decline (Figure 3).ConclusionTo our knowledge, this is the first feasibility study assessing the CMI at preclinical and early clinical stages of AD. Our preliminary results suggest that the DT paradigm is a sensitive method to detect early signs of neurodegeneration and monitor AD progression.