A Novel Tool for Quantitative Assessment of Lower Limb Proprioception: Demonstration with Healthy Adults, Elderly, and Stroke Survivors

Stroke-survivors suffer from impairments in daily functions due to the brain damage that they endured. Elderly adults may have similar impairments because of aging. For some of them, proprioception is often impaired, and this impairment affects motor functions, including gait. Current clinical proprioception assessment is often subjective and not accurate, and the treatment focuses solely on the motor disorders often neglecting the somatosensory impairments. Here, we develop a novel tool and protocol for lower-limb proprioception assessment. We built a measurement setup with magnetic tracking and a support against gravity for the evaluated limb, and designed a protocol for assessing proprioception in both legs using a position-matching test. To control the possible differences in motor abilities between the participants and the different legs, the assessment is performed with (1) position-matching between legs and (2) position recall within the same leg. We analyze the absolute, constant, and variable errors in matching distances, and the size and shape of the error-ellipses. We demonstrated our approach in characterization of lower-limb proprioception impairment among healthy young adults, elderly adults, and stroke-survivors. We expected to see smaller matching errors and variability among the young adults, compared to other groups. Some elderly and stroke survivors have large matching errors and large scattered ellipses that overlap. The young adults have smaller matching errors and barely any overlap. This tool can improve current rehabilitation interventions by allowing treatment of somatosensory or motor aspects as needed for each individual, especially for elderly and for patients suffering from proprioceptive impairments.