Symmetry of sensory loss in developing diabetic sensory polyneuropathy.

The medical literature presents diabetic sensory polyneuropathy (DSPN) as an axonal length-dependent symmetric pathology producing a stocking-like pattern of anesthesia in the lower extremities. This has been based on anecdotal reports. Objective research has shown that damage may not occur in a purely length-dependent manner. A stocking distribution of sensory loss is atypical, and plantar sensory loss predominates. A single-blinded, age-matched, control/experimental study was performed of the symmetry of nerve damage in developing DSPN. Control (n = 46) and experimental (n = 83) subjects were examined. The patterns of sensory loss and the severity of axonal damage were evaluated. The right/left symmetry of pathology was recorded for each individual. Although there was not a stocking pattern of anesthesia found in developing DSPN, the pattern and severity of anesthesia were found to be generally symmetric. The severity of sensory impairment was symmetric at the dorsal foot (93%), lateral foot (95%), and plantar foot (69%). The most predominant site of sensory impairment was also symmetric (81%). This argues against a purely metabolic etiology for axonal damage. An anatomic component is implied. Further research will need to include examination of the unique physical characteristics of predominantly affected nerves.