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Visualizing hyperactivation in neurodegeneration based on prefrontal oxygenation: A comparative study of mild Alzheimer's disease, mild cognitive impairment, and healthy controls

Background: Cognitive performance is relatively well preserved during early cognitive impairment owing to compensatory mechanisms. Methods: We explored functional near-infrared spectroscopy (fNIRS) alongside a semantic verbal fluency task (SVFT) to investigate any compensation exhibited by the prefr...

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Main Authors: Yap, K.H., Ung, W.C., Ebenezer, E.G.M., Nordin, N., Chin, P.S., Sugathan, S., Chan, S.C., Yip, H.L., Kiguchi, M., Tang, T.B.
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Published: Frontiers Media S.A. 2017
Online Access:https://www.scopus.com/inward/record.uri?eid=2-s2.0-85030153101&doi=10.3389%2ffnagi.2017.00287&partnerID=40&md5=01b7257646a7a8c1c9783ebb5f8d9f5d
http://eprints.utp.edu.my/19393/
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spelling my.utp.eprints.193932018-04-20T00:41:07Z Visualizing hyperactivation in neurodegeneration based on prefrontal oxygenation: A comparative study of mild Alzheimer's disease, mild cognitive impairment, and healthy controls Yap, K.H. Ung, W.C. Ebenezer, E.G.M. Nordin, N. Chin, P.S. Sugathan, S. Chan, S.C. Yip, H.L. Kiguchi, M. Tang, T.B. Background: Cognitive performance is relatively well preserved during early cognitive impairment owing to compensatory mechanisms. Methods: We explored functional near-infrared spectroscopy (fNIRS) alongside a semantic verbal fluency task (SVFT) to investigate any compensation exhibited by the prefrontal cortex (PFC) in Mild Cognitive Impairment (MCI) and mild Alzheimer's disease (AD). In addition, a group of healthy controls (HC) was studied. A total of 61 volunteers (31 HC, 12 patients with MCI and 18 patients with mild AD) took part in the present study. Results: Although not statistically significant, MCI exhibited a greater mean activation of both the right and left PFC, followed by HC and mild AD. Analysis showed that in the left PFC, the time taken for HC to achieve the activation level was shorter than MCI and mild AD (p = 0.0047 and 0.0498, respectively); in the right PFC, mild AD took a longer time to achieve the activation level than HC and MCI (p = 0.0469 and 0.0335, respectively); in the right PFC, HC, and MCI demonstrated a steeper slope compared to mild AD (p = 0.0432 and 0. 0107, respectively). The results were, however, not significant when corrected by the Bonferroni-Holm method. There was also found to be a moderately positive correlation (R = 0.5886) between the oxygenation levels in the left PFC and a clinical measure Mini-Mental State Examination (MMSE) score in MCI subjects uniquely. Discussion: The hyperactivation in MCI coupled with a better SVFT performance may suggest neural compensation, although it is not known to what degree hyperactivation manifests as a potential indicator of compensatory mechanisms. However, hypoactivation plus a poorer SVFT performance in mild AD might indicate an inability to compensate due to the degree of structural impairment. Conclusion: Consistent with the scaffolding theory of aging and cognition, the task-elicited hyperactivation in MCI might reflect the presence of compensatory mechanisms and hypoactivation in mild AD could reflect an inability to compensate. Future studies will investigate the fNIRS parameters with a larger sample size, and their validity as prognostic biomarkers of neurodegeneration. © 2017 Yap, Ung, Ebenezer, Nordin, Chin, Sugathan, Chan, Yip, Kiguchi and Tang. Frontiers Media S.A. 2017 Article PeerReviewed https://www.scopus.com/inward/record.uri?eid=2-s2.0-85030153101&doi=10.3389%2ffnagi.2017.00287&partnerID=40&md5=01b7257646a7a8c1c9783ebb5f8d9f5d Yap, K.H. and Ung, W.C. and Ebenezer, E.G.M. and Nordin, N. and Chin, P.S. and Sugathan, S. and Chan, S.C. and Yip, H.L. and Kiguchi, M. and Tang, T.B. (2017) Visualizing hyperactivation in neurodegeneration based on prefrontal oxygenation: A comparative study of mild Alzheimer's disease, mild cognitive impairment, and healthy controls. Frontiers in Aging Neuroscience, 9 (SEP). http://eprints.utp.edu.my/19393/
institution Universiti Teknologi Petronas
building UTP Resource Centre
collection Institutional Repository
continent Asia
country Malaysia
content_provider Universiti Teknologi Petronas
content_source UTP Institutional Repository
url_provider http://eprints.utp.edu.my/
description Background: Cognitive performance is relatively well preserved during early cognitive impairment owing to compensatory mechanisms. Methods: We explored functional near-infrared spectroscopy (fNIRS) alongside a semantic verbal fluency task (SVFT) to investigate any compensation exhibited by the prefrontal cortex (PFC) in Mild Cognitive Impairment (MCI) and mild Alzheimer's disease (AD). In addition, a group of healthy controls (HC) was studied. A total of 61 volunteers (31 HC, 12 patients with MCI and 18 patients with mild AD) took part in the present study. Results: Although not statistically significant, MCI exhibited a greater mean activation of both the right and left PFC, followed by HC and mild AD. Analysis showed that in the left PFC, the time taken for HC to achieve the activation level was shorter than MCI and mild AD (p = 0.0047 and 0.0498, respectively); in the right PFC, mild AD took a longer time to achieve the activation level than HC and MCI (p = 0.0469 and 0.0335, respectively); in the right PFC, HC, and MCI demonstrated a steeper slope compared to mild AD (p = 0.0432 and 0. 0107, respectively). The results were, however, not significant when corrected by the Bonferroni-Holm method. There was also found to be a moderately positive correlation (R = 0.5886) between the oxygenation levels in the left PFC and a clinical measure Mini-Mental State Examination (MMSE) score in MCI subjects uniquely. Discussion: The hyperactivation in MCI coupled with a better SVFT performance may suggest neural compensation, although it is not known to what degree hyperactivation manifests as a potential indicator of compensatory mechanisms. However, hypoactivation plus a poorer SVFT performance in mild AD might indicate an inability to compensate due to the degree of structural impairment. Conclusion: Consistent with the scaffolding theory of aging and cognition, the task-elicited hyperactivation in MCI might reflect the presence of compensatory mechanisms and hypoactivation in mild AD could reflect an inability to compensate. Future studies will investigate the fNIRS parameters with a larger sample size, and their validity as prognostic biomarkers of neurodegeneration. © 2017 Yap, Ung, Ebenezer, Nordin, Chin, Sugathan, Chan, Yip, Kiguchi and Tang.
format Article
author Yap, K.H.
Ung, W.C.
Ebenezer, E.G.M.
Nordin, N.
Chin, P.S.
Sugathan, S.
Chan, S.C.
Yip, H.L.
Kiguchi, M.
Tang, T.B.
spellingShingle Yap, K.H.
Ung, W.C.
Ebenezer, E.G.M.
Nordin, N.
Chin, P.S.
Sugathan, S.
Chan, S.C.
Yip, H.L.
Kiguchi, M.
Tang, T.B.
Visualizing hyperactivation in neurodegeneration based on prefrontal oxygenation: A comparative study of mild Alzheimer's disease, mild cognitive impairment, and healthy controls
author_facet Yap, K.H.
Ung, W.C.
Ebenezer, E.G.M.
Nordin, N.
Chin, P.S.
Sugathan, S.
Chan, S.C.
Yip, H.L.
Kiguchi, M.
Tang, T.B.
author_sort Yap, K.H.
title Visualizing hyperactivation in neurodegeneration based on prefrontal oxygenation: A comparative study of mild Alzheimer's disease, mild cognitive impairment, and healthy controls
title_short Visualizing hyperactivation in neurodegeneration based on prefrontal oxygenation: A comparative study of mild Alzheimer's disease, mild cognitive impairment, and healthy controls
title_full Visualizing hyperactivation in neurodegeneration based on prefrontal oxygenation: A comparative study of mild Alzheimer's disease, mild cognitive impairment, and healthy controls
title_fullStr Visualizing hyperactivation in neurodegeneration based on prefrontal oxygenation: A comparative study of mild Alzheimer's disease, mild cognitive impairment, and healthy controls
title_full_unstemmed Visualizing hyperactivation in neurodegeneration based on prefrontal oxygenation: A comparative study of mild Alzheimer's disease, mild cognitive impairment, and healthy controls
title_sort visualizing hyperactivation in neurodegeneration based on prefrontal oxygenation: a comparative study of mild alzheimer's disease, mild cognitive impairment, and healthy controls
publisher Frontiers Media S.A.
publishDate 2017
url https://www.scopus.com/inward/record.uri?eid=2-s2.0-85030153101&doi=10.3389%2ffnagi.2017.00287&partnerID=40&md5=01b7257646a7a8c1c9783ebb5f8d9f5d
http://eprints.utp.edu.my/19393/
_version_ 1738656063775834112
score 13.211869

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