Assessing for Sensorimotor and Cognitive Impairments in ALS Patients

Abstract

ALS is a debilitating neurodegenerative disease characterized by the degeneration of both upper and lower motor neurons (Gordon 2013). Recently, it has been found that up to 50% of individuals with ALS have evidence of cognitive impairment and approximately 15% meet the diagnostic criteria for frontotemporal dementia (FTD). Moreover, the pathology of ALS has been found to be widespread (Neumann et al., 2006; Robberecht and Philips, 2013). To this day, traditional clinical examinations have been used to assess ALS patients, which have been shown to be subjective. This led us to ask the question: could introducing a novel method of assessment (robotics) give us a more objective and reproducible approach? Also, could using a different method reveal other impairments caused by ALS reflecting the evolving picture of its more widespread pathology? In this thesis, we assessed 14 subjects, 12 diagnosed with ALS and 2 diagnosed with PLS. The assessment of subjects consisted of two parts: 1) a clinical assessment and 2) a robotic assessment using the KINARM Exoskeleton. We then correlated the performance of subjects on the robotic tasks with their clinical examination results. The robotic assessment consisted of 8 tasks, divided into 4 categories 1) Motor tasks which included Visual guided reaching, and Ball on Bar. 2) Motor-cognitive tasks included Reverse visually guided reaching (RVGR), Object hit, and Object hit and avoid. 3) Cognitive tasks included Spatial Span, and Trail Making A and B 4) A sensory task, Arm Position Matching. The results of this thesis indicate that subjects showed various deficits along a spectrum of sensorimotor and cognitive functions, related to various networks in the brain. Some tasks and parameters were more commonly impaired such as the Reaction Time and RVGR. Some subjects were more impaired in sensorimotor tasks than cognitive tasks and vice versa. Robotic tasks were shown to be objective and accurate; most subjects could tolerate them. Examining a larger cohort of subjects in the future could enable us to further observe for patterns of impairment and phenotypes within the ALS population.