Functional assessment of neurologic impairment: track analysis in diabetic and compression neuropathies.

A laboratory approach to measuring neurologic impairment has been developed that is applicable to systemic disease as well as localized nerve injury. This approach compares individual parameters of the experimental rat hind footprint (walking track) with weight- and sex-matched control track parameters; classic mathematical indexing is not utilized. The normal track data obtained for the Sprague-Dawley rat showed a significant increase in print length (PL), toe spread (TS), and intermediate toe spread (ITS) with increasing rat weight. A significant difference between male and female rats above 400 gm also was noted. For a localized injury (sciatic nerve cut), this approach demonstrated that the contralateral hind footprint was a "compensated" rather than a normal track. This approach to track analysis also was capable of demonstrating progressive neurologic impairment for a sciatic nerve compression model and a systemic disease such as diabetes, as well as demonstrating reversal of these abnormal patterns when the "disease state" was treated.