PERIPHERAL NEUROPATHY EFFECT ON ANKLE INVERSION AND EVERSION DETECTION THRESHOLDS

A servo-controlled foot platform was used to quantify, in upright stan ce, the thresholds for sensing ankle inversion and eversion movements in seven geriatric patients with peripheral neuropathy (PN) confirmed by nerve conduction studies and seven age- and gender-matched (C) cont rols with normal nerve conduction function, The PN group had a 3.6-fol d larger (p = 0.0026) threshold (mean [SD] 1.37[1.74]degrees) for perc eiving the presence and direction of an ankle rotation at a 75% rate o f success (TH75) than did the C group (0.3[0.17]degrees). Inversion ac uity was approximately twice that of eversion acuity in both groups, T he PN group demonstrated better proprioceptive acuity in unipedal stan ce than in bipedal stance, whereas no such difference was found in the C group. Semiquantitative clinical tests of PN group proprioception a t the ankle performed in the seated position failed to demonstrate sig nificant differences from controls save in one case; however, the resu lts of such tests at the toe were abnormal in all patients, In the ger iatric population, PN is associated with deficits in ankle propriocept ion known theoretically to hamper maintenance of unipedal balance. It is significant that these deficits are associated with a clinically de monstrable loss of position sense at the toe but not the ankle. (C) 19 95 by the American Congress of Rehabilitation Medicine and the America n Academy of Physical Medicine and Rehabilitation