Sensory relearning after nerve repair.

One of the challenges in reconstructive surgery is to ensure hand sensibility is regained after median nerve repair. We assessed tactile gnosis in 54 patients (mean age 32 [range 4-72] years) after repair of transected median or ulnar nerves at the wrist level. We found that there is a well-defined critical period for sensory relearning after nerve repair. There is an optimum capacity below age 5-10 years followed by a rapid decline, which levels out after puberty. The curve correlates with previously published data on critical periods for language acquisition among immigrants. Recovery of functional sensibility after nerve repair is based on a learning process and in many ways is analogous to learning a second language.