Sensory neuropathy may cause central neuronal reorganization but does not respecify perceptual quality or localization of sensation.
OBJECTIVE
Functional reorganization in the somatosensory network after peripheral nerve lesions has been suspected to modify the clinical expression of symptoms. However, no conclusive evidence exists to support this notion. We addressed this question by investigating the topographic distribution of the subjective sensory report in various chronic human mononeuropathies.


METHODS
We report the clinical results of 86 patients who were diagnosed with meralgia paresthetica, 86 patients with ulnar neuropathy at the elbow, and 203 patients with carpal tunnel syndrome.


RESULTS
In the carpal tunnel syndrome group, 10% of the patients exhibited a spread of sensory symptoms beyond the innervation territory of the median nerve. As previously reported, this spread was contingent upon an indirect compressive lesion of the ulnar nerve at the wrist. In all of the patients who were affected with meralgia paresthetica or ulnar neuropathy at the elbow, the peripheral referral of sensation was always within the anatomic distribution of the affected nerve.


CONCLUSIONS
In human neuropathies, the projected sensory symptoms are restricted to the innervation territories of the affected nerves, with no extraterritorial spread. Thus, the somatosensory localization function remains accurate, despite the central reorganization that presumably occurs after nerve injury. We conclude that reorganization of the sensory connections within the central nervous system after peripheral nerve injury in humans is a clinically silent adaptive phenomenon.
Department of Neurological, Neurosurgical, and Behavioural Sciences, Clinical Neurophysiology Unit, University of Siena, Siena, Italy. ginanneschi@unisi.it
Federica
F
Ginanneschi
Mauro
M
Mondelli
Alessandro
A
Rossi
D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002349:Carpal Tunnel Syndrome / Q000503:physiopathology; D004576:Electromyography; D005073:Evoked Potentials, Somatosensory / Q000502:physiology*; D005260:Female; D020428:Femoral Neuropathy; D005385:Fingers / Q000294:innervation; D007839:Functional Laterality; D006801:Humans; D008297:Male; D008875:Middle Aged; D020422:Mononeuropathies / Q000473:pathology* / Q000503:physiopathology*; D009408:Nerve Compression Syndromes / Q000503:physiopathology; D009431:Neural Conduction / Q000502:physiology*; D011795:Surveys and Questionnaires; D020424:Ulnar Neuropathies / Q000503:physiopathology; D055815:Young Adult