Department of Neurology, National Hospital Organization, Sendai-Nishitgaga Hospital, Kagitori-honcho, Taihaku-ku, Sendai, Japan.
Department of Behavioral Neurology and Cognitive Neuroscience, Seiryo-machi, Aoba-ku, Sendai, Japan.
J Parkinsons Dis. 2014;4(2):181-7. doi: 10.3233/JPD-130277.
Dementia is one of the most debilitating symptoms of Parkinson's disease (PD), but the development of dementia is still difficult to predict at early stages of the disease. We recently found that hyposmia, one of the most typical non-motor features of PD, was a predictive feature of Parkinson's disease with dementia (PDD). In that work, multivariate logistic analysis identified severe hyposmia and visuoperceptual impairment as independent risk factors for subsequent dementia within 3 years. The patients with severe hyposmia had an 18.7-fold increase in their risk of dementia for each 1 SD (2.8) decrease in scores on the odor stick identification test for Japanese (OSIT-J). We also found an association between severe hyposmia and a specific pattern of cerebral metabolic decline, which was identical to findings observed in PDD. Furthermore, volumetric magnetic resonance imaging analyses demonstrated close relationships between olfactory dysfunction and atrophy of focal brain structures, including the amygdala and other limbic structures. Our findings suggest that brain regions related to olfactory function are closely associated with cognitive decline and that severe hyposmia is a prominent clinical feature that predicts the subsequent development of PDD. We have now started a randomized, double-blind study using donepezil for the PD group with severe hyposmia. We hope that this clinical trial will allow us to establish a therapeutic intervention that can improve the prognosis of advanced PD.
痴呆是帕金森病（PD）最具致残性的症状之一，但在疾病早期仍难以预测痴呆的发生。我们最近发现，嗅觉减退是 PD 最典型的非运动特征之一，是帕金森病伴痴呆（PDD）的预测特征。在这项工作中，多元逻辑分析确定严重嗅觉减退和视知觉障碍是 3 年内发生痴呆的独立危险因素。嗅觉减退严重的患者，其气味识别测试（OSIT-J）得分每降低 1 个标准差（2.8），其痴呆风险增加 18.7 倍。我们还发现严重嗅觉减退与大脑代谢下降的特定模式之间存在关联，这与 PDD 中的观察结果一致。此外，容积磁共振成像分析表明嗅觉功能障碍与包括杏仁核和其他边缘结构在内的局灶性脑结构的萎缩密切相关。我们的研究结果表明，与嗅觉功能相关的脑区与认知能力下降密切相关，严重嗅觉减退是预测 PDD 后续发展的突出临床特征。我们现在已经开始对嗅觉减退严重的 PD 患者进行多奈哌齐的随机、双盲研究。我们希望这项临床试验能够为我们提供一种治疗干预措施，改善晚期 PD 的预后。
