1st Department of Neurology, Institute of Psychiatry and Neurology, Warsaw, Poland.
Curr Alzheimer Res. 2011 Sep;8(6):689-98. doi: 10.2174/156720511796717212.
At 3 years after diagnosis, the risk of Alzheimer disease (AD) for patients with mild cognitive impairment (MCI) is estimated to be 18% to 30%. To improve treatment of patients at high dementia risk there is a need for a better prediction of the risk for transition from MCI to AD. Olfactory deficits are a hypothetical predictor of conversion form MCI to AD. Furthermore, several studies point at volumetric reduction of medial temporal lobe structures as predictors of conversion form MCI to AD. The primary aim of this study was to evaluate whether investigations of odor deficits in MCI combined with neuropsychological tests and MRI examinations can improve prediction of the development of dementia.
Changes in olfactory functions, cognitive functions, and volume of medial temporal lobe structures (hippocampus, parahippocampal gyrus, and amygdala) were evaluated in a 24-month follow-up study in 49 MCI patients and 33 controls.
In the MCI group, a prediction of strong cognitive functions deterioration based on poor performance in Olfactory Identification tests shows sensitivity of 57% and specificity of 88%. The test based on cognitive functions only shows a sensitivity of 44%, and 89%, respectively. Combined tests having a criteria of poor olfactory identification performance AND poor results of neuropsychological tests showed a sensitivity of 100% and specificity of 84%. Furthermore, correlation was found between the results of Olfactory Identification tests at baseline and deterioration of cognitive functions at follow up. Odor identification threshold did not appear to be a dementia predictor. A correlation of progress of cognitive function deterioration, odor identification deterioration, and decrease of volume of the hippocampus was also observed.
Prediction of MCI to dementia conversion can be improved by supplementing the neuropsychological tests with odor identification tests. A follow up study of hippocampus volume reduction, OI performance and cognitive functions deterioration will further increase prediction accuracy.
在诊断后 3 年，轻度认知障碍（MCI）患者患阿尔茨海默病（AD）的风险估计为 18%至 30%。为了提高高痴呆风险患者的治疗效果，需要更好地预测从 MCI 向 AD 转化的风险。嗅觉缺陷是从 MCI 向 AD 转化的假设预测指标。此外，多项研究指出内侧颞叶结构体积减少是从 MCI 向 AD 转化的预测指标。本研究的主要目的是评估 MCI 患者嗅觉缺陷的调查结果结合神经心理学测试和 MRI 检查是否能提高痴呆发展的预测能力。
在一项 24 个月的随访研究中，对 49 名 MCI 患者和 33 名对照者的嗅觉功能、认知功能和内侧颞叶结构（海马体、海马旁回和杏仁核）体积变化进行了评估。
在 MCI 组中，基于嗅觉识别测试中表现不佳的强认知功能恶化预测显示敏感性为 57%，特异性为 88%。仅基于认知功能的测试显示敏感性为 44%，特异性为 89%。联合测试，即嗅觉识别表现不佳和神经心理学测试结果不佳的标准，显示敏感性为 100%，特异性为 84%。此外，在基线时嗅觉识别测试的结果与随访时认知功能的恶化之间存在相关性。嗅觉识别阈值似乎不是痴呆的预测指标。还观察到认知功能恶化的进展、嗅觉识别恶化和海马体体积减少之间的相关性。
通过将嗅觉识别测试补充到神经心理学测试中，可以提高对 MCI 向痴呆转化的预测。进一步的研究将观察海马体体积减少、OI 表现和认知功能恶化的后续研究，将进一步提高预测的准确性。
