Measuring vibration threshold with a graduated tuning fork in normal aging and in patients with polyneuropathy

Objective-To provide clinically useful vibration threshold normal values. Methods-The graduated Rydel-Seiffer tuning fork was evaluated in 198 healthy controls and 59 patients with a polyneuropathy. The measures were done in triplicate at four locations: the distal interphalangeal joint of the index finger, ulnar styloid process, interphalangeal joint of the hallux, and internal malleolus. The values obtained with this tuning fork in healthy controls and patients with polyneuropathy were compared with the values of an electronic device, the Vibrameter. Results-Vibration sense was better perceived in the arms compared with the legs. There was a significant age related decline of vibration sense at all locations. The values from the Rydel-Seiffer tuning fork and the Vibrameter were significantly correlated in both groups. The sensitivity of these two instruments for the four sites examined in the polyneuropathy group ranged from 29-76% and 31-73%, respectively and was the highest at the hallux for both instruments. Conclusion-This study provides clinical useful normal values of vibration threshold for the Rydel-Seiffer tuning fork. This is a simple and easily applicable instrument that assesses vibration sense semiquantitatively and should therefore have a place in routine neurological examination.