A new electrophysiological biomarker of mild cognitive impairment

　Dr. Yamasaki and Prof. Tobimatsu (Dept. of Clinical Neurophysiology, Kyushu University) previously reported that radial optic flow (OF) motion perception was selectively impaired in patients with mild cognitive impairment (MCI, prodromal stage of Alzheimer’s disease) using visual evoked potentials (VEPs) (Journal of Alzheimer’s Disease, 2012).
　We found that VEPs with radial OF motion stimuli can discriminate MCI patients from healthy controls with a high specificity and high sensitivity. Our two studies could provide a non-invasive, cost effective and quantitative biomarker for early diagnosis of MCI. Since the OF perception is closely related to the abilities of navigation and driving, OF-VEPs may be useful for detecting their impairment in MCI. This study was collaborated with the Memory Clinic at Kyushu University Hospital.
　This research achievement has been published on May 23, 2016, in the online edition of the Journal of Alzheimer’s Disease.

For more information about this research, see
Yamasaki et al.: A potential VEP biomarker for mild cognitive impairment: Evidence from selective visual deficit of higher-level dorsal pathway.
DOI:10.3233/JAD-150939

Fig. Radial OF motion
(a) Radial OF is the visual motion seen during observers’ self-movement and is known to be important for daily life because it provides cues about the heading direction and the three-dimensional structure of the visual environment. This motion is mainly processed in the posterior parietal lobe.
Patients with Alzheimer’s disease and MCI exhibit the decline in abilities of navigation and driving due to the impairment of OF perception caused by posterior parietal dysfunction.

(b) Radial OF motion used in this study. We can create radial OF motion stimuli easily using random dots. Dots radiate from the focus of expansion, which corresponds to the observer’s direction of heading.