外傷性脳損傷における言語性IQ低下因子についての検討

Lowered VIQ Level Following Traumatic Brain Injury

　要旨　外傷性脳損傷（以下，脳外傷）患者は，その後遺症として，高次脳機能障害を合併することがしばしばみられる。われわれは2000～2002年に，神奈川リハビリテーション病院にて脳外傷と診断した延べ人数237名のうち，知的機能の評価としてWAIS-Rを行い，VIQがPIQより有意に低下した12例について，後方視的にFunctional Independence Measure（FIM），神経心理学的検査，画像診断での病巣について検討した。その結果，VIQ値がPIQ値に比べて有意に低下する群の存在が確認された。また，脳挫傷などによる損傷部位が異なっていても，神経心理学的検査結果が一致することが確認できた。さらに，VIQの低下群でもPIQの「符号」やTrail Making Test，語の流暢性は低下することがわかった。この結果は，以前に筆者らが報告した「びまん性軸索損傷32例」の結果と類似しており，高次脳機能障害の主因が軸索の損傷であることが改めて推察された。

　A Patient with traumatic brain injury（TBI）is often associated with incidence of congnitive dysfunction as a sequela. We have conducted WAIS-R to 237 patients who were diagnosed as TBI at the Kanagawa Rehabilitation Hospital in order to assess their intellectual function. Twelve patients, whose VIQ being marked significantry lower than PIQ, were retrospectively analyzed in terms of their Functional Independence Measure（FIM）, neuropsychological test results and lesions found in diagnostic images. In consequence, presence of a patient group whose VIQ level is significantly lowered due to the TBI sequela is recognized, in addition to a finding that trauma sites of cerebral contusion or other incidents are not necessarily corresponding to the results of neuropsychological test. Furthermore, based on an observation that those patients with lowerd VIQ level are also associated with aggravation of PIQ ‘digit symbol’, Trail Making Test, or word fluency levels. This result was before similar with the result of “32 cases of DAI（diffuse axonal injury）” which authors reported, and it was guessed anew that the main factor of a cognitive dysfunction was damage on axon.

（Received : August 16, 2004）