Use of Monofilament in the Detection of Foot Lesions in Older Adults

The purpose of this study was to compare Semmes-Weinstein monofilament testing between elderly and young patients in both a diabetic and nondiabetic population. Monofilament mapping (10 g) was performed on 115 patients: 74 who were greater than 60 years of age (47 with diabetes) and 41 who were younger than 60 years (20 with diabetes). Sensations were assessed at 15 predefined pressure/risk points. Sensations were found to have perfect correlation between the same point on the left and right foot (r = 1.0) for each of the 15 points. The data for the 15 points were divided in 2 subsets: one for 8 points similar to a validated method and another with 7 new points on the dorsum and ankle area. Scores on both subsets differed significantly by age group (P < .0001) and diabetes status (P < .001), with older patients and patients with diabetes having higher scores. Analysis of covariance was used to estimate 15-point scores for the 4 combinations of age group and diabetes status, adjusting for foot ulceration, callus, deformity, and ischemia. In older patients without diabetes, each subset score was used to detect future neuropathy if 4 or more points were insensitive. The detections agreed in 37 of 47 cases. In all 10 cases of disagreement, the 7-point subset detected no neuropathy, suggesting that inclusion of the additional points could improve diagnostic specificity. The significant differences noted between young and old patients suggest the importance of aging-related changes, and raise questions about current scoring methods for detection of neuropathy in older adults with diabetes.