Effect of Socks on the Assessment of Vibration Sensation

Objective. To investigate the difference between the measurement of vibration sensation without and with socks. Material and Methods. Fifty healthy volunteers (H group) and 19 patients with diabetic polyneuropathy (PNP group) were included. The sites of measurement were the great toe (GT) and medial malleolus (MM). A standard 128？Hz tuning fork was used in the measurements. Results. Mean duration of vibration sensations without and with socks was as follows: in the H group, 19.4 ± 4.2 and 19.5 ± 4.2？s at GT and 15.1 ± 3.3 and 14.6 ± 3.3？s at MM; in the PNP group, 13.4 ± 3.8 and 12.7 ± 4.1？s at GT and 11.9 ± 3.8 and 11.7 ± 3.4？s at MM. No significant difference was found between the measurements without and with socks, except those found at the MM in group H ( ). This significant difference was further analyzed in terms of effect size which was concluded to be practically insignificant (Cohen’s ). Shorter mean vibration duration was measured at MM as compared to GT that could be explained by the damping effect. Conclusions. Wearing socks of moderate thickness does not have any important effect on the duration of vibration sensation. This might be considered as a reflection of the remarkable properties of vibration sensation. 1. Introduction The evaluation of vibration sensation informs the clinician about the integrity of mechanoreceptors in the skin, rapidly conducting large-diameter afferent fibers in the peripheral nerves and the dorsal column-medial lemniscus pathways in the central nervous system [1, 2]. Therefore, diminished vibration sensation is an important finding in the diagnosis of disorders affecting the dorsal column-medial lemniscal system and may also be an early sign of peripheral neuropathies [3]. It is known in everyday practice that patients, due to the physical properties of this sensory modality, can perceive vibration through layers of clothes [4]. However, the validity of examining vibration sensation over the clothes is unknown. This recently resulted in a debate during a case presentation in our clinic in which one of the authors tried to perform the examination on a clothed subject for the sake of speed. The present study was designed under the inspiration of this dispute with the hope of providing some new insights into the characteristics of vibration sensation. 2. Methods 2.1. Subjects Fifty healthy volunteers (H group; median age was 37 years, 22 male) and 19 patients with diabetic polyneuropathy (PNP group; median age was 57 years, 5 male) were included in the study (Table 1). The H group mainly consisted of volunteer