Graphesthesia

Definition

Graphesthesia is the ability to recognize writing on the skin. Its name derives from Greek grapha (writing) and aisthesis(perception). Graphesthesia was first described in 1920 by Sir Henry Head. In the sensorimotor exam, with the patient’s eyes closed, the examiner writes single numbers or letters on the palm of the hand or fingertips with something relatively blunt, like the dull point of a pencil. Considered a measure of fine tactual discrimination, the inability to decipher the numbers or letters being written could be the result of lesions anywhere in the medial lemniscal system, from the dorsal columns to the cortex. If more of the elementary functions (such as vibration and proprioception) are intact, then the inability to perform on this task might suggest a functional disturbance in the hand region of the postcentral gyrus. Typically, the performance on the right is compared with that on the left to help identify the lateralized deficits. Body parts other than the...