Brain：嗅觉检查有助帕金森症早期诊断

近日，最新一期的《大脑》（Brain）杂志发表了日本研究人员的发现，通过嗅觉检查，能够对帕金森氏症患者容易出现的认知障碍进行早期诊断，今后有望对帕金森氏症患者的认知障碍进行早期治疗。

东京大学副教授武田笃率领的研究小组报告说，研究小组从2009年开始，对尚未表现出认知障碍的44名帕金森氏症患者，实施了识别12种气味的检查。结果发现，有10名存在重度嗅觉障碍的患者此后出现了认知障碍，而没有嗅觉障碍的人则没有出现认知障碍。

帕金森氏症是由于脑部多巴胺神经细胞减少，导致手脚震颤和身体僵硬的难治之症，而且并发认知障碍的概率很高。

对于帕金森氏症的震颤等症状，现在已可用药物疗法改善，因此他们认为：“如果能够迅速对认知障碍进行治疗，将有助于改善帕金森氏症患者的症状。”（生物谷Bioon.com）

doi:10.1093/brain/awr321
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Severe olfactory dysfunction is a prodromal symptom of dementia associated with Parkinson's disease: a 3 year longitudinal study

Toru Baba, Akio Kikuchi, Kazumi Hirayama, Yoshiyuki Nishio, Yoshiyuki Hosokai, Shigenori Kanno, Takafumi Hasegawa, Naoto Sugeno, Masatoshi Konno, Kyoko Suzuki, Shoki Takahashi, Hiroshi Fukuda, Masashi Aoki, Yasuto Itoyama, Etsuro Mori and Atsushi Takeda

Dementia is one of the most debilitating symptoms of Parkinson's disease. A recent longitudinal study suggests that up to 80% of patients with Parkinson's disease will eventually develop dementia. Despite its clinical importance, the development of dementia is still difficult to predict at early stages. We previously identified olfactory dysfunction as one of the most important indicators of cortical hypometabolism in Parkinson's disease. In this study, we investigated the possible associations between olfactory dysfunction and the risk of developing dementia within a 3-year observation period. Forty-four patients with Parkinson's disease without dementia underwent the odour stick identification test for Japanese, memory and visuoperceptual assessments, 18F-fluorodeoxyglucose positron emission tomography scans and magnetic resonance imaging scans at baseline and 3 years later. A subgroup of patients with Parkinson's disease who exhibited severe hyposmia at baseline showed more pronounced cognitive decline at the follow-up survey. By the end of the study, 10 of 44 patients with Parkinson's disease had developed dementia, all of whom had severe hyposmia at baseline. The 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 the score of odour stick identification test for Japanese. We also found an association between severe hyposmia and a characteristic distribution of cerebral metabolic decline, which was identical to that of dementia associated with Parkinson's disease. Furthermore, volumetric magnetic resonance imaging analyses demonstrated close relationships between olfactory dysfunction and the atrophy of focal brain structures, including the amygdala and other limbic structures. Together, 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 Parkinson's disease dementia.