Letter to the Editor

Abstract

We have read the article entitled “Diabetic Driving Studies—Part 1: Brake Response Time in Diabetic Drivers With Lower Extremity Neuropathy” (JFAS 56:568–572, 2017) published in the May/June issue of your Journal with outmost interest because it has presented the data from a valuable and important study in an attempt to find an answer to a substantial question. The presented results bring an interesting finding that the study participants with a history of any ulceration, amputation, or Charcot neuroarthropathy (n = 136 trials [68.0%]) had a mean brake response time that was shorter (0.721 ± 0.139 seconds) and the range narrower (range 0.50 to 1.30 seconds) compared with participants without such a history (n = 64 trials [32.0%]) who had a brake response time of 0.833 ± 0.229 (range 0.51 to 1.68) seconds (p < .001). From the clinical viewpoint, we would expect the opposite, because these complications usually signal a greater degree of lower extremity neuropathy. In a search for an explanation, in addition to the comparatively small number of participants, a question was raised of possible hypoglycemia which could have occurred during or shortly before some of “the brake tests,” thus would have accidentally influenced the subjects' reaction time. Furthermore, the study population consisted of type 2 diabetes mellitus patients—their treatment, however, was not described. The wide range of hemoglobin A1c values (5.5% to 10.1%) suggests that the study group might have also included patients treated with hypoglycemic drugs such as insulin or sulphonylurea derivatives. We would, therefore, like to ask Meyr et al to specify whether the blood glucose levels were checked, a history of recent hypoglycemia had been determined before “the brake test,” and whether all the patients involved had been treated with nonhypoglycemic agents. We also, with great respect, suggest considering the question of hypoglycemia into the protocol of this interesting and important study, if its continuation is planned. Diabetic Driving Studies—Part 1: Brake Response Time in Diabetic Drivers With Lower Extremity NeuropathyThe Journal of Foot and Ankle SurgeryVol. 56Issue 3PreviewAlthough the effect of lower extremity pathology and surgical intervention on automobile driving function has been a topic of contemporary interest, we are unaware of any analysis of the effect of lower extremity diabetic sensorimotor neuropathy on driving performance. The objective of the present case-control investigation was to assess the mean brake response time in diabetic drivers with lower extremity neuropathy compared with that of a control group and a brake response safety threshold. The driving performances of participants were evaluated using a computerized driving simulator with specific measurement of the mean brake response time and frequency of abnormally delayed brake responses. Full-Text PDF Author's Reply to Letter to the EditorThe Journal of Foot and Ankle SurgeryVol. 59Issue 2PreviewThanks for your letter and interest in our investigation. We were also surprised that the group with a history of specific diabetic foot pathology (ulceration, partial foot amputation, Charcot neuroarthropathy) relatively outperformed the group with only evidence of lower extremity sensorimotor neuropathy. However, as stated in the Discussion, we continue to believe that this statistically significant finding has limited clinical significance, “as both groups demonstrated mean brake response times in excess of a recommended driving safety threshold of 0.700 seconds.” We are unaware of any investigation (including our own) that has measured the effect of acute blood glucose levels, hypoglycemic events, and/or specific pharmacologic agents on brake response times, and agree that this might represent an interesting avenue for future investigations. Full-Text PDF