Comparison of a simple method for quantitation of intraepidermal nerve fibres with a standard image analysis method using hypothenar skin.

To compare a simpler method for counting intraepidermal nerve fibres with a standard computer based image analysis method in normal subjects with skin taken from the hypothenar region. In 40 healthy controls (mean age 41.1 years, range 21-71, 24 Chinese, 11 Indian, 5 Malay, 30 females) intraepidermal nerve fibres per length of epidermis were determined using immunoperoxidase staining with the panaxonal antibody PGP 9.5. Under brightfield microscopy, two methods of determining the length of the epidermis were compared. A simpler method employing a microscope intraocular lens ruler was compared with the more complex gold standard using image software analysis . Intraepidermal nerve fibres per length of epidermis using the intraocular ruler method were 3.07 nerve fibres/mm (2SD 1.56). The image software analysis obtained values of 3.05 nerve fibres/mm (2SD 1.54). Correlation between the two tests was excellent (r=0.999 p= or <0.00001). Epidermal nerve fibre counts from hypothenar skin are lower than in more proximal sites. A simple method for counting intraepidermal nerve fibres produces results similar to those using standard software image analysis. This should help the implementation of this technique for wider use.