Back to basics: ankle reflex in the evaluation of peripheral neuropathy in type 2 diabetes mellitus

Ankle reflex is a simple screening tool frequently used in the detection of peripheral neuropathy.

The purpose of this study is to assess the performance characteristics of ankle reflex in detecting diabetic peripheral neuropathy (DPN) by evaluating the sensitivity, specificity and the predictive ability of the ankle reflex, a component of Neuropathy Disability Score (NDS) with reference to Nerve Conduction Studies (NCS).

A total of 151 patients with type 2 diabetes were assessed (47 males, 104 females). Grading of neuropathy was done using Neuropathy Symptom Score (NSS), NDS and NCS. Patients were divided into two groups, those with abnormal NCS (Group 1) and those with normal NCS (Group 2). Demographic characteristics, biochemistry, NSS and NDS were assessed between the two groups. Taking NCS as the gold standard, sensitivity, specificity and predictive ability of the ankle reflex were calculated and compared with other tests included in NDS, namely vibration sense, superficial pain and temperature sensation.

There were 59 (39.1%) patients in Group 1 and 92 (60.9%) in Group 2. NSS and NDS demonstrated strong positive association with NCS. Taking NCS as the gold standard, ankle reflex yielded the highest sensitivity and specificity (91.5 and 67.4%, respectively), closely followed by that of vibration sense.

Ankle reflex is a powerful screening tool with high sensitivity and negative predictive value, but a combination of ankle reflex and vibration sense has superior sensitivity and specificity compared with either of them done alone for the detection of DPN in clinical settings.