Proprioception more impaired distally than proximally in subjects with hemispheric dysfunction

Holmes noted that with hemispheric injuries proprioceptive disturbances wer e more marked in the distal than proximal limb segments and proposed that t his difference was related to the size of cortical sensory representations. An alternative hypothesis is that sensation from distal segments projects to the contralateral hemisphere and sensation from proximal segments projec ts to both hemispheres. Selective hemispheric anesthesia was used to test t hese alternative hypotheses and revealed a decrement in distal but not prox imal proprioception with hemispheric anesthesia, thereby supporting the bil ateral projection hypothesis.