Influence of the diabetic neuropathy on the behavior of electromyographic and sensorial responses in treadmill gait

Objective. We describe and interpret self-cadence treadmill walking by neuropathic diabetic subjects under biomechanical and somatosensorial considerations. Design. EMG variables during stance phase of neuropathic diabetic subjects were acquired and analyzed. We also evaluated sensorial and motor aspects of the feet and legs. Methods. The experimental procedures are divided as follows: (a) determination of the sensitive cronaxie and pain tolerance in selected plantar areas, (b) determination and description of temporal aspects of EMG patterns of the vastus lateralis, tibialis anterior and lateral gastrocnemius of both sides during treadmill walking. We analyze and compare the results of the sensitive cronaxie, pain tolerance and the EMG parameters obtained by two experimental groups: diabetic neuropathic (n=20) and non-diabetic control subjects (n=20). Results. The somatosensorial responses and pain tolerance threshold in the diabetic neuropathic group were significantly higher and considered far from the normal patterns. The EMG responses of the thigh and leg muscles in the diabetic neuropathic group were delayed if compared to the normal recruitment pattern, especially the tibialis anterior and vastus lateralis. Conclusions. These findings lead us to conclude that probably central and/or peripheral control mechanisms of the gait of neuropathic diabetic patients are altered due to somatosensorial and motor deficits. The mechanism of load reduction during walking was considered inefficient because of the activation delay of the vastus lateralis and tibialis anterior. We have concluded that the peripheral diabetic neuropathy damages not only somatosensorial and motor sources but also intrinsic mechanisms of motor control leading to alterations in the ankle efficiency in gait. This resulting distal inefficiency compromises some of the principal requirements for gait, such as progression and balance.