Relationship between the changes in blood flow and volume in the finger during a Braille character discrimination task

Purpose We hypothesized that skin blood flow ( SBF ) of fingers are modulated during concentrated finger perception and that the changes in SBF reflect fluctuations in finger volume ( FV ). The aim of this study, therefore, was examine the relationship between the changes in SBF and FV during Braille reading. Methods We measured SBF of the finger, cutaneous vascular conductance ( CVC ), FV , and arterial blood pressure during Braille reading performed under blind conditions in thirty healthy subjects. The subjects were instructed to read a flat plate with raised letters (Braille reading) for 15 seconds using their forefinger, and to touch a blank plate as a control for the Braille discrimination procedure. Results Arterial blood pressure slightly increased during Braille reading but remained unchanged during the touching of the blank plate. SBF , CVC , and FV were reduced during Braille reading (decreased by −26%, −29%, and −0.3 mL/100 mL respectively). Furthermore, a significant relationship was observed between the changes in SBF and FV ( r =.613) during Braille reading. Conclusion These results suggested that SBF of fingers is modulated during concentrated finger perception, and that the variability of blood flow reflects the response in FV .