Effects of ageing and Alzheimer disease on haemodynamic response function: a challenge for event-related fMRI
Effects of ageing and Alzheimer disease on haemodynamic response function: a challenge for event-related fMRI
复制标题
DOI：
10.1049/htl.2017.0005
复制
发表时间：
2017-06-01
影响因子：
2.1
通讯作者：
Shalchy, Mahsa Alizadeh
中科院分区：
文献类型：
--
作者：
Asemani, Davud;Morsheddost, Hassan;Shalchy, Mahsa Alizadeh
功能磁共振成像(FMRI)可以生成大脑图像，显示由于感觉、认知或运动任务而产生的神经元活动。血流动力学反应功能(HRF)可作为区分阿尔茨海默病(AD)和健康老龄化的生物标志物。由于血氧水平依赖的fMRI信号非常微弱和噪声，特别是对老年人来说，为了有效地区分AD，需要一种稳健的方法来估计HRF。在应用最小描述长度小波作为额外的去噪步骤后，用反卷积算法代替前人工作中使用的平均方法来估计HRF。比较了青年组、非痴呆组和老年痴呆组在视觉和运动区的HRF幅值峰值。以前的研究经常报道年轻人和老年人之间的HRF峰值幅度有显著差异。作者的实验表明，与年轻人和老年人(无论是痴呆症还是非痴呆症)相比，HRF峰值没有显著差异。这表明，以前关于老年人和年轻人HRF峰值的相互矛盾的研究结果是源于fMRI数据中的噪声贡献。
Functional magnetic resonance imaging (fMRI) can generate brain images that show neuronal activity due to sensory, cognitive or motor tasks. Haemodynamic response function (HRF) may be considered as a biomarker to discriminate the Alzheimer disease (AD) from healthy ageing. As blood-oxygenation-level-dependent fMRI signal is much weak and noisy, particularly for the elderly subjects, a robust method is necessary for HRF estimation to efficiently differentiate the AD. After applying minimum description length wavelet as an extra denoising step, deconvolution algorithm is here employed for HRF estimation, substituting the averaging method used in the previous works. The HRF amplitude peaks are compared for three groups HRF of young, non-demented and demented elderly groups for both vision and motor regions. Prior works often reported significant differences in the HRF peak amplitude between the young and the elderly. The authors' experimentations show that the HRF peaks are not significantly different comparing the young adults with the elderly (either demented or non-demented). It is here demonstrated that the contradictory findings of the previous studies on the HRF peaks for the elderly compared with the young are originated from the noise contribution in fMRI data.