The influence of spatial working memory on ipsilateral remembered proprioceptive matching in adults with cerebral...

Somatosensation is frequently impaired in individuals with Cerebral Palsy (CP). This includes the sense of proprioception, which is an important contributor to activities of daily living. One means of determining proprioceptive deficits in CP has been use of an Ipsilateral Remembered (IR) position matching test. The IR test requires participants to replicate, without vision, memorized joint/limb positions previously experienced by the same (i.e. ipsilateral) effector. Given the memory component inherent to this task, the present study sought to determine the extent to which IR proprioceptive matching might be influenced by known spatial working memory deficits. Eleven adults with CP underwent IR elbow position matching, where blindfolded individuals were given either a short (2 s) or long (15 s) duration to memorize the target elbow angle. A standard clinical measure of spatial working memory (i.e. Corsi block-tapping task) was also administered. The results showed that the directional (i.e. constant) error produced across trials did not differ between the short and long target duration conditions. However, it was found that participants were significantly more consistent in their matches (i.e. had smaller variable errors) when given more time to encode proprioceptive targets in the long duration condition. The benefit of having more time was greatest for those individuals with the highest variable errors in the short target condition, and a significant association was seen between improvements in variable error and greater performance on 4/5 spatial working memory measures. These findings provide the best evidence to date that IR position matching tests are influenced by spatial working memory.