The Impact of Type 2 Diabetes and Associated Diabetic Peripheral Neuropathy on Grip Force Control and Hand Function
Yahya, Abdalghani A
University of Kansas
Physical Therapy & Rehabilitation Sciences
Copyright held by the author.
MetadataShow full item record
There is cumulative evidence that fine motor skills and hand function are deficient in individuals with type 2 diabetes (T2D) and associated diabetic peripheral neuropathy (DPN). This might impact their ability to perform essential tasks such as buttoning a shirt, picking up pills, and monitoring blood sugar. Understanding the nature of such deficits is of utmost importance. This dissertation explores the sensorimotor involvement to deficits in hand dexterity: Sensory such as proprioception and motor such as grip force control. Several questions were addressed. First, does T2D and DPN cause finger proprioception deficits? Second, does T2D and DPN affect grip force control? Third, what is the role of sensation, specifically proprioception, in motor performance? Because little is known about testing proprioception in a manner relevant to dexterity tasks, data presented in Chapter 2 tested the reliability and feasibility of a novel device and methods of pinch proprioception. Twenty-one healthy subjects attempted to actively reproduce a target position between the index finger and thumb without visual feedback over two consecutive days. Nineteen subjects performed the same procedure, but in a one-day setting and under two conditions: With and without vibration applied to the dorsal part of their dominant hand. Two additional subjects with T2D and DPN were tested as well. Similar results of pinch proprioception were achieved between the two consecutive days indicating that the device and methods were reliable in tracking proprioception between the index finger and thumb. Also, disruption of pinch proprioception sense was achieved as subjects were less accurate in matching the target position under the influence of vibration. The two subjects with T2D and DPN showed less accuracy in matching the target position indicating that their sense of proprioception is affected by their disease. While the pinch proprioception device and methods showed promise in detecting proprioception deficits in subjects with T2D and DPN as shown in Chapter 2, we did not know whether DPN is the leading cause of such deficits. It is known that DPN causes sensory deficits hindering proprioception in the lower extremities, but the evidence is limited on the hands. To address this limitation, Chapter 3 describes an experiment with 13 subjects with T2D and DPN, 11 subjects with T2D without DPN, and 12 healthy subjects; all groups were age-matched. All subjects were tested for pinch proprioception utilizing the same device and methods described in Chapter 2. It was found that the accuracy and precision of the pinch proprioception were particularly affected in subjects with T2D and DPN. The T2D without DPN subjects showed similar findings to the healthy subjects indicating that DPN is a contributing factor to these deficits. Therefore, building on the findings from Chapter 2, it was concluded that damage to muscle spindles associated with DPN is very likely what caused pinch proprioceptive deficits. In Chapter 4, the focus shifted to grip force control. Several recent studies have shown deficits in controlling grip force in people with diabetes (type 1 and T2D). For instance, some studies showed an increase in grip force magnitude while others demonstrated that this variable was decreased in diabetic subjects with and without DPN. The same subjects described in the previous chapter were asked to grip and lift an object and then hold it at a specific height to address the inconsistent findings. Grip force magnitude, as well as temporal parameters of grip force control, were analyzed. It was found that the grip force magnitude was higher in subjects with T2D and DPN, and they took longer to perform the lifting task as compared to those with T2D without DPN and healthy subjects. These data provide evidence that T2D by itself does not present with any deficits in grip force control, and DPN might be responsible for deficits in grip force magnitude and temporal parameters. Finally, Chapter 5 is focused on the study of dexterous motor activities that involve object manipulation and require sensory feedback that plays a major role in adjusting grip forces when holding an object. Deficits in hand dexterity in people with T2D have been shown via Jebsen-Taylor Hand Function Test (JTHFT) and Moberg Pickup Test (MPUT); i.e., subjects spent more prolonged time to perform functional tasks. In addition to the finding of impairments in pinch proprioception, grip force control, and hand dexterity in people with T2D and DPN, decrements in pinch proprioception were positively correlated with longer time to perform dexterity tasks. Other aspects of sensory deficits (tactile sensation) were more associated with higher grip force magnitude. It was concluded that while tactile sensation was more associated with higher grip forces, pinch proprioception deficits appear to contribute to increasing the time needed to perform a lifting task. Overall, the results suggest that DPN is a major concern that causes proprioceptive, grip force control, and hand dexterity problems. The integrity of proprioceptive signals, as well as tactile sensation, affect different profiles of grip force control to different degrees. Proprioception is more related to timing while tactile sensation appears to affect the grip force production. Therefore, intact sensory information (tactile and proprioceptive) is necessary to perform dexterity tasks which seem to be problematic for subjects who suffer from T2D and DPN. Clinicians should be aware of the nature of hand dexterity deficits in the presence of DPN when screening and developing rehabilitation programs.
- Dissertations 
- KU Med Center Dissertations and Theses 
Items in KU ScholarWorks are protected by copyright, with all rights reserved, unless otherwise indicated.
We want to hear from you! Please share your stories about how Open Access to this item benefits YOU.