Relative sensory sparing in the diabetic foot implied through vibration testing

BACKGROUND: The dorsal aspect of the hallux is often cited as the anatomic location of choice for vibration testing in the feet of diabetic patients. To validate this preference, vibration tests were performed and compared at the hallux and 5th metatarsal head in diabetic patients with established neuropathy. METHODS: Twenty-eight neuropathic, diabetic patients and 17 non-neuropathic, non-diabetic patients underwent timed vibration testing (TVT) with a novel 128 Hz electronic tuning fork (ETF) at the hallux and 5th metatarsal head. RESULTS: TVT values in the feet of diabetic patients were found to be reduced at both locations compared to controls. Unexpectedly, these values were significantly lower at the hallux (P<0.001) compared to the 5th metatarsal head. CONCLUSION: This study confirms the hallux as the most appropriate location for vibration testing and implies relative sensory sparing at the 5th metatarsal head, a finding not previously reported in diabetic patients.