Two-point discrimination values vary depending on test site, sex and test modality in the orofacial region: a preliminary study

Abstract

The two-point discrimination (TPD) test is one of the most commonly used neurosensory tests to assess mechanoperception in the clinical settings. While there have been numerous studies of functional sensibility of the hand using TPD test, there have been relatively not enough reports on TPD in the orofacial region. Objective The aims of the present study were to determine the normal values of TPD in the six trigeminal sites (the forehead, cheek, mentum, upper lip, lower lip, and the tongue tip) and to investigate the effect of the site, sex, and test modality on the TPD perception.Material and Methods Forty healthy volunteers consisting of age-matched men (20) and women (20) with a mean age of 27.1 years were recruited. One examiner performed the TPD test using a simple hand-operated device, i.e., by drawing compass with a blunt or sharp-pointed tip. The static TPD with a blunt-pointed tip (STPDB), moving TPD with a blunt-pointed tip (MTPDB), and static TPD with a sharp-pointed tip (STPDS) were measured. The predictors were the site, sex, and test modality, and the outcome variable was the TPD value. Three-way ANOVA was used for statistics.Results The analysis showed a significant effect of the site, sex and test modality on the TPD values. Significant differences between the test sites were observed with the descending order from the forehead and cheek>mentum>upper lip and lower lip>tongue tip and index finger. Women showed lower TPD values than those of men. The STPDS measurements were consistently lower than those of the STPDB and MTPDB.Conclusions The normal values of TPD in this study suggest that the cheek and forehead were less sensitive than other regions evaluated and women were more sensitive than men. The STPDS was the most sensitive test modality.

The Role of Demographic and Symbolic Features in Clinical Arabic Graphesthesia Testing

“…It is possible that controlling for certain variables such as the orientation of symbols, hand positions, and the direction of writing in our study decreased the spatial processing demand needed to interpret the stimuli, leading to the differences in performance by gender. Gleaning from studies on 2-point discrimination, a lower threshold of detection has been found in women [19,20]; however, the exact reason for these performance differences may not be from cognitive privileges bestowed by gender. For example, studies that looked at 2-point discrimination in men and women found that detection thresholds decreased with increasing body fat ratio [21] or with decreasing fingertip size [22] (fingertip graphesthesia), attributes more commonly found in women.…”

Tactile trigeminal region acuity in temporomandibular disorders: A reliability and cross‐sectional study

“…Neurosensory tests aim to evaluate somatosensory alterations . One of the most relevant aspects to evaluate is tactile perception, by means of sensory tests that evaluate the fibres type A myelinic fibres .…”

“…One of the most relevant aspects to evaluate is tactile perception, by means of sensory tests that evaluate the fibres type A myelinic fibres . Of all the tests used to assess tactile sensation, 2‐PD has been widely used to assess the condition of mechanoreceptors . It is widely documented that tactile acuity varies according to the body area assessed .…”

“…[12][13][14] Neurosensory tests aim to evaluate somatosensory alterations. 15 One of the most relevant aspects to evaluate is tactile perception, by means of sensory tests that evaluate the fibres type A myelinic fibres. 16 Of all the tests used to assess tactile sensation, 2-PD has been widely used to assess the condition of mechanoreceptors.…”

“…16 Of all the tests used to assess tactile sensation, 2-PD has been widely used to assess the condition of mechanoreceptors. 15 It is widely documented that tactile acuity varies according to the body area assessed. 17 The sensory neural pathways in charge of the oro-facial zone such as the lip and tongue, or those of the fingers are particularly specialised in the processing of spatial information; therefore, damage to these pathways is likely to manifest more prominently as a loss of spatial acuity.…”