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Takamiya N1,2, Yamasaki T2
1Prefectural University of Hiroshima, Department of Physical Therapy, Mihara City, Japan, 2Kyusyu University, Neurological Institute, Department of Clinical Neurophysiology, Fukuoka, Japan
Background: The inferior parietal lobules (IPLs) have been considered an important area for the integration of some modalities such as the visual and somatosensory. Impairment of the region with IPLs results in conditions, such as unilateral spatial neglect, apraxia, developmental disability, and dementia. By using visual evoked potentials (VEPs) originating from the IPLs, we recently found that higher-level processing in the dorsal stream is impaired in patients with amnestic mild cognitive impairment (aMCI) and Alzheimer's disease (AD). In addition to the importance of early and sensitive detection, improving physical activity becomes a protective factor against aMCI and AD. Therefore, we believe that that it is necessary to investigate the interaction between physical function and IPL functions and to clarify how physical activity affects IPL and contributes to the prevention of aMCI and AD.
Purpose: In this study, we aimed to clarify the interaction between the dysfunction of the dorsal visual stream and physical and cognitive functions. We hypothesized that spatial perception somehow involves physical function.
Methods: Thirty-four healthy right-handed participants (24 females) aged >60 years (mean±SD age, 72.8±4.7 years) were recruited from among native Japanese community-dwelling elderly. Their VEPs were recorded when stimuli for Japanese kana words and radial optic flow (OF) motion were presented. We extracted the three major components, namely the N170 for kana words originating from IPLs, the N170 for OF-motion generated by the fifth visual cortex (V5)/ middle temporal (MT), and the P200 for OF motion based on the IPL. We used neuropsychological tests, and physical function and exercise tolerance tests, including immediate and delayed recall of logical memory in the Wechsler Memory Scale-Revised (immediate and delayed LM WMS-R), Japanese Version of the Montreal Cognitive Assessment (MoCA-J), and 6-minute walk test (6MWT). For statistical analysis, we examined the correlation between the VEPs and immediate/delayed LM WMS-R, MoCA-J, and distance and number of steps in the 6MWT using Pearson correlation.
Results: The N170 for kana words, N170 for OF motion, and P200 for OF motion were clearly observed. A negative correlation was found between P200 latency for OF motion and immediate LM WMS-R (r=−0.41, p=0.016), P200 latency for OF motion and delayed LM WMS-R (r=−0.36, p=0.034), N170 amplitude for kana words and MoCA-J (r=−0.43, p=0.011). A significant positive correlation was found only between the N170 amplitude for OF motion and number of steps in the 6MWT (r=0.35,p=0.042).
Conclusion(s): The major findings of this study were as follows:
1) The VEPs to the higher dorsal stimuli exhibited a correlation with neuropsychological scores.
2) The cadence, not the walking distance, might have influenced the IPL function.
Implications: In Japan, with the rapidly aging population and high life expectancy, dementia is a major problem. To prevent aMCI, VEPs are suggested to be effective as highly sensitive biomarkers for early detection of aMCI, and walking guidance to increase cadence might be useful.
Keywords: Visual evoked potentials, inferior parietal lobules, community-dwelling elderly
Funding acknowledgements: This study was supported in part by the Grant-in-Aid for Young Scientists(B) JSPS KAKENHI Grant No. 17K13063.
Purpose: In this study, we aimed to clarify the interaction between the dysfunction of the dorsal visual stream and physical and cognitive functions. We hypothesized that spatial perception somehow involves physical function.
Methods: Thirty-four healthy right-handed participants (24 females) aged >60 years (mean±SD age, 72.8±4.7 years) were recruited from among native Japanese community-dwelling elderly. Their VEPs were recorded when stimuli for Japanese kana words and radial optic flow (OF) motion were presented. We extracted the three major components, namely the N170 for kana words originating from IPLs, the N170 for OF-motion generated by the fifth visual cortex (V5)/ middle temporal (MT), and the P200 for OF motion based on the IPL. We used neuropsychological tests, and physical function and exercise tolerance tests, including immediate and delayed recall of logical memory in the Wechsler Memory Scale-Revised (immediate and delayed LM WMS-R), Japanese Version of the Montreal Cognitive Assessment (MoCA-J), and 6-minute walk test (6MWT). For statistical analysis, we examined the correlation between the VEPs and immediate/delayed LM WMS-R, MoCA-J, and distance and number of steps in the 6MWT using Pearson correlation.
Results: The N170 for kana words, N170 for OF motion, and P200 for OF motion were clearly observed. A negative correlation was found between P200 latency for OF motion and immediate LM WMS-R (r=−0.41, p=0.016), P200 latency for OF motion and delayed LM WMS-R (r=−0.36, p=0.034), N170 amplitude for kana words and MoCA-J (r=−0.43, p=0.011). A significant positive correlation was found only between the N170 amplitude for OF motion and number of steps in the 6MWT (r=0.35,p=0.042).
Conclusion(s): The major findings of this study were as follows:
1) The VEPs to the higher dorsal stimuli exhibited a correlation with neuropsychological scores.
2) The cadence, not the walking distance, might have influenced the IPL function.
Implications: In Japan, with the rapidly aging population and high life expectancy, dementia is a major problem. To prevent aMCI, VEPs are suggested to be effective as highly sensitive biomarkers for early detection of aMCI, and walking guidance to increase cadence might be useful.
Keywords: Visual evoked potentials, inferior parietal lobules, community-dwelling elderly
Funding acknowledgements: This study was supported in part by the Grant-in-Aid for Young Scientists(B) JSPS KAKENHI Grant No. 17K13063.
Topic: Older people; Neurology; Health promotion & wellbeing/healthy ageing
Ethics approval required: Yes
Institution: Prefectural University of Hiroshima
Ethics committee: Ethics Committee of the Prefectural University of Hiroshima
Ethics number: 16MH027
All authors, affiliations and abstracts have been published as submitted.
