Di Sclafani V, Clark H W, Tolou-Shams M, Bloomer C W, Salas G A, Norman D, Fein G
Department of Psychiatry, University of California, San Francisco, USA.
J Int Neuropsychol Soc. 1998 Nov;4(6):559-65. doi: 10.1017/s1355617798466049.
Studies of Alzheimer's disease patients show that individuals with larger premorbid brains have a later onset of disease, or a lessened severity of cognitive impairment, or both. This may be due to a "functional reserve" associated with the greater number of neurons and synapses available in larger brains. We used magnetic resonance imaging and the MicroCog Assessment of Cognitive Functioning to examine the association between intracranial volume (premorbid brain size) and neuropsychological function in abstinent crack-cocaine and crack-cocaine-alcohol dependent individuals. There were no significant differences between the crack-only and the crack-alcohol dependent participants in neuropsychological performance or in intracranial volume. The abstinent cocaine-dependent individuals (both crack-only and crack-alcohol) were significantly impaired in many neuropsychological domains. Intracranial volume accounted for a significant proportion of the variance in neuropsychological performance. This result is consistent with the finding in the Alzheimer's literature that larger brains can maintain function to a greater degree, or for a longer period of time, in the face of cerebral disease or insult. Functional reserve may be a heretofore little recognized protective mechanism of the brain that has consequences for the severity of expression of cerebral disease or insult throughout life.
对阿尔茨海默病患者的研究表明，病前脑容量较大的个体发病较晚，或认知障碍的严重程度较轻，或两者兼而有之。这可能是由于与较大脑内可用的更多神经元和突触相关的“功能储备”。我们使用磁共振成像和认知功能的微观认知评估来研究戒断的快克可卡因依赖者和快克可卡因 - 酒精依赖者的颅内体积（病前脑大小）与神经心理功能之间的关联。仅使用快克可卡因的参与者和同时使用快克可卡因与酒精的参与者在神经心理表现或颅内体积方面没有显著差异。戒断的可卡因依赖个体（包括仅使用快克可卡因和同时使用快克可卡因与酒精的个体）在许多神经心理领域都有显著损害。颅内体积在神经心理表现的方差中占很大比例。这一结果与阿尔茨海默病文献中的发现一致，即较大的脑在面对脑部疾病或损伤时能够在更大程度上或更长时间内维持功能。功能储备可能是一种迄今为止很少被认识到的大脑保护机制，它对一生中脑部疾病或损伤的严重程度表达有影响。
