Predictive Value of Somatosensation for Manual Dexterity and Upper Limb Motor Function in Stroke Survivors

Objectives: One of the most disabling impairments following stroke is upper limb impairment. Despite the important role of somatosensory function in motor control and high prevalence of somatosensory deficits in stroke survivors, little attention has been paid to its effect on UE motor function in chronic stroke survivors. Thus, the aim of this study is to explore the correlation between different somatosensations and manual dexterity as well as UE motor function in these patients. Methods: In this correlational study, 225 chronic stroke survivors (112 female and 113 male) participated, selected by simple non-probability method among the stroke survivors admitted to the rehabilitation centers in Tehran. The lower-order somatosensations, including light touch and wrist Proprioception, were evaluated by Weinstein Enhanced Sensory Test (WEST) and Wrist Position Sense Test (WPST), respectively. The higher-order somatosensations were measured by static and moving 2-Point Discrimination (s2PD and m2PD, respectively), Hand Active Sensation Test (HAST) and Haptic Object Recognition Test (HORT). Gross and fine manual dexterity and UE motor function were assessed using Box-Block Test (BBT), Purdue Pegboard Test (PPT) and Wolf Motor Function Test (WMFT), respectively. Results: The multiple regression models showed that WPST alone accounted for the 38.8%- 56.6% of the variance in manual dexterity and UE motor function. The WEST was the second most significant predictor in all regression models. The HORT, m2PD and HAST explained a small percent of the variance in regression models.  Discussion: These results suggest that treatments that target somatosensory impairments, especially wrist Proprioception and light touch, may be particularly important for improving manual dexterity and UE motor function in chronic stroke survivors.