Vagus nerve stimulation in dementia: A scoping review of clinical and pre-clinical studies

Ronald Kamoga; Godfrey Zari Rukundo; Samuel Kalungi; Wilson Adriko; Gladys Nakidde; Celestino Obua; Johnes Obongoloch; Amadi Ogonda Ihunwo; Ronald Kamoga; Godfrey Zari Rukundo; Samuel Kalungi; Wilson Adriko; Gladys Nakidde; Celestino Obua; Johnes Obongoloch; Amadi Ogonda Ihunwo

doi:10.3934/Neuroscience.2024024

AIMS Neuroscience

2024, Volume 11, Issue 3: 398-420. doi: 10.3934/Neuroscience.2024024

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Review

Vagus nerve stimulation in dementia: A scoping review of clinical and pre-clinical studies

1.
Department of Anatomy, Mbarara University of Science and Technology, P.O. Box 1410, Mbarara, Uganda
2.
Department of Psychiatry, Mbarara University of Science and Technology, P.O.Box 1410, Mbarara, Uganda
3.
Makerere University, School of health sciences, Department of Pathology. Kampala, Uganda
4.
Library department, Mbarara University of Science and Technology, P.O. Box 1410, Mbarara Uganda
5.
Faculty of Nursing and Health Sciences, Bishop Stuart University, Mbarara, Uganda
6.
Department of Pharmacology, Mbarara University of Science and Technology, P.O.Box 1410, Mbarara, Uganda
7.
Department of Biomedical engineering, Mbarara University of Science and Technology, P.O.Box 1410, Mbarara, Uganda
8.
University of the Witwatersrand, School of Anatomical Sciences, Faculty of Health Sciences, Johannesburg, South Africa

Received: 14 July 2024 Revised: 13 September 2024 Accepted: 19 September 2024 Published: 27 September 2024

Background
Dementia is a prevalent, progressive, neurodegenerative condition with multifactorial causes. Due to the lack of effective pharmaceutical treatments for dementia, there are growing clinical and research interests in using vagus nerve stimulation (VNS) as a potential non-pharmacological therapy for dementia. However, the extent of the research volume and nature into the effects of VNS on dementia is not well understood. This study aimed to examine the extent and nature of research activities in relation to the use of VNS in dementia and disseminate research findings for the potential utility in dementia care.
Methods
We performed a scoping review of literature searches in PubMed, HINARI, Google Scholar, and the Cochrane databases from 1980 to November 30th, 2023, including the reference lists of the identified studies. The following search terms were utilized: brain stimulation, dementia, Alzheimer's disease, vagal stimulation, memory loss, Deme*, cognit*, VNS, and Cranial nerve stimulation. The included studies met the following conditions: primary research articles pertaining to both humans and animals for both longitudinal and cross-sectional study designs and published in English from January 1st, 1980, to November 30th, 2023; investigated VNS in either dementia or cognitive impairment; and were not case studies, conference proceedings/abstracts, commentaries, or ordinary review papers.
Findings and conclusions
We identified 8062 articles, and after screening for eligibility (sequentially by titles, abstracts and full text reading, and duplicate removal), 10 studies were included in the review. All the studies included in this literature review were conducted over the last three decades in high-income geographical regions (i.e., Europe, the United States, the United Kingdom, and China), with the majority of them (7/10) being performed in humans. The main reported outcomes of VNS in the dementia cases were enhanced cognitive functions, an increased functional connectivity of various brain regions involved in learning and memory, microglial structural modifications from neurodestructive to neuroprotective configurations, a reduction of cerebral spinal fluid tau-proteins, and significant evoked brain tissue potentials that could be utilized to diagnose neurodegenerative disorders. The study outcomes highlight the potential for VNS to be used as a non-pharmacological therapy for cognitive impairment in dementia-related diseases such as Alzheimer's disease.
- cognitive impairment,
- Dementia,
- Alzheimer's disease,
- vagus nerve stimulation,
- brain stimulation
Citation: Ronald Kamoga, Godfrey Zari Rukundo, Samuel Kalungi, Wilson Adriko, Gladys Nakidde, Celestino Obua, Johnes Obongoloch, Amadi Ogonda Ihunwo. Vagus nerve stimulation in dementia: A scoping review of clinical and pre-clinical studies[J]. AIMS Neuroscience, 2024, 11(3): 398-420. doi: 10.3934/Neuroscience.2024024

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Abstract

Background

Dementia is a prevalent, progressive, neurodegenerative condition with multifactorial causes. Due to the lack of effective pharmaceutical treatments for dementia, there are growing clinical and research interests in using vagus nerve stimulation (VNS) as a potential non-pharmacological therapy for dementia. However, the extent of the research volume and nature into the effects of VNS on dementia is not well understood. This study aimed to examine the extent and nature of research activities in relation to the use of VNS in dementia and disseminate research findings for the potential utility in dementia care.

Methods

We performed a scoping review of literature searches in PubMed, HINARI, Google Scholar, and the Cochrane databases from 1980 to November 30th, 2023, including the reference lists of the identified studies. The following search terms were utilized: brain stimulation, dementia, Alzheimer's disease, vagal stimulation, memory loss, Deme*, cognit*, VNS, and Cranial nerve stimulation. The included studies met the following conditions: primary research articles pertaining to both humans and animals for both longitudinal and cross-sectional study designs and published in English from January 1st, 1980, to November 30th, 2023; investigated VNS in either dementia or cognitive impairment; and were not case studies, conference proceedings/abstracts, commentaries, or ordinary review papers.

Findings and conclusions

We identified 8062 articles, and after screening for eligibility (sequentially by titles, abstracts and full text reading, and duplicate removal), 10 studies were included in the review. All the studies included in this literature review were conducted over the last three decades in high-income geographical regions (i.e., Europe, the United States, the United Kingdom, and China), with the majority of them (7/10) being performed in humans. The main reported outcomes of VNS in the dementia cases were enhanced cognitive functions, an increased functional connectivity of various brain regions involved in learning and memory, microglial structural modifications from neurodestructive to neuroprotective configurations, a reduction of cerebral spinal fluid tau-proteins, and significant evoked brain tissue potentials that could be utilized to diagnose neurodegenerative disorders. The study outcomes highlight the potential for VNS to be used as a non-pharmacological therapy for cognitive impairment in dementia-related diseases such as Alzheimer's disease.

Acknowledgments

I acknowledge the contribution of Dr. Nduhukire Abraham and Dr. Evelyn Kirabo Biseki for their participation in data extraction and screening. I appreciate Mrs. Sarah Lubega Nambi for your invaluable emotional and financial support during the preparation of this work.

Authors contribution

Contributions to the scoping review's conceptualization and design came from RK, GZR, GN, AOI, and JO. WA and RK performed the systematic search across all databases. The data extraction and article screening were carried out by GN, RK, GZR and SK. Each author made a contribution to the data's analysis and interpretation. The scoping review was originally written by RK, and all authors edited the document to bring it to its current state and approved the submitted version.

Conflict of interest

All authors declared no conflict of interest.

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