Vibration testing with the Rydel-Seiffer tuning fork
In a large series of patients, routine clinical testing was compared to quantitative vibratory testing (QVT). Neuromuscular physicians more often overestimated than underestimated vibratory loss when compared to QVT. In a large series of patients, routine clinical vibratory testing was compared to quantitative vibratory testing (QVT).(1) Neuromuscular physicians more often overestimated than underestimated vibratory loss when compared to QVT. There have been attempts to standardize timed vibration testing.(2)
The 64 Hz Rydel-Seiffer tuning fork (RSTF) provides a more quantitative assessment of vibratory sensation. There is a black and white display of two arrows and two sets of numbers from 2 to 8 (Figure).
The RSTF method is no more time consuming than routine vibratory testing and and is less cumbersome than timed vibratory testing; some have suggested it replace traditional testing. The results correlate with QVT. In a series of 184 subjects, quantitative vibration testing with the RSTF correlated with the amplitude of the sural sensory nerve action potential.(3) Panosyan, et al reported a discrepancy between the readings of the black vs the white triangle and suggested greater accuracy is possible by darkening the white triangle with a marker, conforming to the original (1903) design featuring 2 black triangles.(4)
1. Peters EW, Bienfait HM, de Visser M, de Haan RJ. The reliability of assessment of vibration sense. Acta Neurol Scand 2003; 107:293-298.
2. Botez SA, Liu G, Logigian E, Herrmann DN. Is the bedside timed vibration test reliable? Muscle Nerve. 2009;39:221-3.
3. Pestronk A, Florence J, Levine T, et al. Sensory exam with a quantitative tuning fork: rapid, sensitive and predictive of SNAP amplitude. Neurology 2004;62:461–464.
4. Panosyan FB, Mountain JM, Reilly MM, Shy ME, et al. Rydel-Seiffer fork revisited: Beyond a simple case of black and white. Neurology. 2016;87:738-40