How the Impact of Median Neuropathy on Sensorimotor Control Capability of Hands for Diabetes: An Achievable Assessment from Functional Perspectives

Abstract

To comprehend the sensorimotor control ability in diabetic hands, this study investigated the sensation, motor function and precision pinch performances derived from a pinch-holding-up activity (PHUA) test of the hands of diabetic patients and healthy subjects. The precision, sensitivity and specificity of the PHUA test in the measurements of diabetic patients were also analyzed. We hypothesized that the diabetic hands would have impacts on the sensorimotor functions of the hand performances under functionally quantitative measurements. One hundred and fifty-nine patients with clinically defined diabetes mellitus (DM) and 95 age- and gender-matched healthy controls were included. Semmes-Weinstein monofilament (SWM), static and moving two-point discrimination (S2PD and M2PD), maximal pinch strength and precision pinch performance tests were conducted to evaluate the sensation, motor and sensorimotor status of the recruited hands. The results showed that there were significant differences (all p<0.05) in SWM, S2PD, M2PD and maximum pinch strength between the DM and control groups. A higher force ratio in the DM patients than in the controls (p<0.001) revealed a poor ability of pinch force adjustment in the DM patients. The percentage of maximal pinch strength was also significantly different (p<0.001) between the DM and control groups. The sensitivity, specificity and area under the receiver operating characteristic curve were 0.85, 0.51, and 0.724, respectively, for the PHUA test. Statistically significant degradations in sensory and motor functions and sensorimotor control ability were observed in the hands of the diabetic patients. The PHUA test could be feasibly used as a clinical tool to determine the sensorimotor function of the hands of diabetic patients from a functional perspective.

Impacts of elevated glycaemic haemoglobin and disease duration on the sensorimotor control of hands in diabetes patients

“…In practice, precision pinch performance relies on the complex integration of impulses transmitted from sensory receptors, as well as control of muscle effectors. Therefore, it is likely to have better sensitivity and accuracy in determining asymptomatic neuropathy in hands of diabetic patients than pure sensory or strength tests . The use of rather crude methods to prevent objects slipping from their hands, as was found for the patients with longer diabetes duration in the current study, is associated with the development of microangiopathic complications .…”

“…However, the results of the 2PD tests in the current study did not differ significantly between the groups categorized by glycaemic control. There was also no evidence in previous studies regarding the impact of glycaemic control on discriminative sensation of the hand, although a recent study revealed that DM patients might have worse moving and static 2PD sensations compared with the control group [24]. In addition, similar pinch strengths between the two subgroups with different levels of glycaemic control were found in this study, which supports the findings of a recent work with regard to there being no direct correlation between grip muscle strength and the value of HbA 1c [39].…”

Dynamical Coordination of Hand Intrinsic Muscles for Precision Grip in Diabetes Mellitus

“…For example, the patients with DM showed reduced force structural complexity (lower approximate entropy values) than healthy subjects when producing grip force upon a spatially fixed apparatus within 15–50% maximum voluntary contraction (MVC) 11 . Compared to the healthy subjects, the DM patients showed higher force ratio in execution of grip-to-lift task; and the force ratio could serve as indicator to DPN whose sensitivity was 85% and specificity was 51% 10 . The debilitated grip force in DM is associated with reduced tactile sensitivity, blurred afferent inputs and reduced efferent conductivity 10 – 13 , and is related to the impaired neuromuscular control for hand and digits due to the long-term hyperglycemia 4 , 14 – 17 .…”

“…Quantitative evaluation of the hand sensorimotor function provides a useful tool for clinical diagnosis of DPN 10 . Accumulating evidence suggests that the effects of DM on hand sensorimotor function could be observed from precision grip – a fundamental grasping manner with opposable thumb and index finger.…”

Do we underestimate influences of diabetic mononeuropathy or polyneuropathy on hand functional performance and life quality?

“…The prevalence of median neuropathy among diabetes patients has been reported to be approximately 58-82%, based on an electrophysiological study 11 . Electrophysiological measurements can be used to show abnormalities of nerve functioning in the hand, especially with regard to the sensory amplitude of nerve conduction [12][13][14] . The consequences of abnormal sensory functioning of the nerve system as a result of the involvement of an impaired median nerve, ulnar nerve or both, might gradually contribute to different severities of neuropathic signs and symptoms, finally developing as mononeuropathy or polyneuropathy 15,16 .…”