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Unexplained Multi-Sensory Neuropathy Syndrome in Young Tanzanian Adults

29 Pages Posted: 1 Feb 2021

See all articles by Enica Richard Massawe

Enica Richard Massawe

Muhimbili University of Health and Allied Sciences - Department of Otorhinolaryngology

Ndeserua Moshi

Muhimbili University of Health and Allied Sciences

Junkun Ren

Geisel School of Medicine at Dartmouth

Catherine C. Rieke

Geisel School of Medicine at Dartmouth; Dartmouth College - Dartmouth-Hitchcock Medical Center

Albert K. Magohe

Muhimbili University of Health and Allied Sciences

Abigail M. Fellows

Geisel School of Medicine at Dartmouth

Enat A. Arega

Dartmouth College - Dartmouth-Hitchcock Medical Center

Christopher E. Niemczak

Geisel School of Medicine at Dartmouth

Brian P. Jackson

Dartmouth College

Margaret R. Karagas

Geisel School of Medicine at Dartmouth - Department of Epidemiology

Jay C. Buckey

Geisel School of Medicine at Dartmouth; Dartmouth College - Dartmouth-Hitchcock Medical Center

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Abstract

Background: A unique syndrome affecting young adults of unexplained hearing loss often associated with uncorrectable poor visual acuity and lower extremity numbness is endemic in Dar es Salaam. This study characterized the hearing loss, associated it with other symptoms, and gathered information on potential causes.

Methods: Forty-seven patients (23 men, 24 women) <40 years old with a symptom consistent with the syndrome, negative syphilis test, and no head injury history were recruited from Muhimbili National Hospital. 18 controls (10 men, 8 women) were recruited from the same neighborhoods as patients. Hearing ability and cochlear outer hair cell function (distortion-product otoacoustic emissions (DPOAEs)) were assessed, as were visual acuity and color vision. Peripheral neuropathy was evaluated using the Michigan Neuropathy Screening Instrument (MNSI), and physical examination. Blood C-reactive protein levels and toenail trace metal concentrations were measured. Environmental exposures were elicited using a questionnaire. Patients with at least two of the following signs were defined as having the syndrome: poor hearing with normal DPOAEs, vision not correctable to better than 20/30, or a MNSI score greater than 4.

Findings: 29 participants met the case definition. CRP levels did not differ between groups but manganese, cobalt and tin levels were each greater in the cases than controls. No other environmental exposure differences were noted.

Interpretation: Toenail manganese, cobalt, and tin levels were higher in those with the syndrome. These metals are potential neurotoxins suggesting a possible environmental origin for this unique and debilitating syndrome.

Funding Statement: Hitchcock Foundation at the Dartmouth-Hitchcock Medical Center.

Declaration of Interests: The authors have no financial or personal relationships that could inappropriately bias their work.

Ethics Approval Statement: The research protocol was approved by the Committee for the Protection of Human Subjects of Dartmouth College and the Research Ethics Committee of Muhimbili University for Health and Allied Sciences. All participants gave written informed consent or parental consent and minor assent.

Keywords: Unexplained acquired hearing loss, young adults, developing country

Suggested Citation

Massawe, Enica Richard and Moshi, Ndeserua and Ren, Junkun and Rieke, Catherine C. and Magohe, Albert K. and Fellows, Abigail M. and Arega, Enat A. and Niemczak, Christopher E. and Jackson, Brian P. and Karagas, Margaret R. and Buckey, Jay C., Unexplained Multi-Sensory Neuropathy Syndrome in Young Tanzanian Adults. Available at SSRN: https://ssrn.com/abstract=3764555 or http://dx.doi.org/10.2139/ssrn.3764555

Enica Richard Massawe (Contact Author)

Muhimbili University of Health and Allied Sciences - Department of Otorhinolaryngology ( email )

Dar-es-Salaam
Tanzania

Ndeserua Moshi

Muhimbili University of Health and Allied Sciences ( email )

UPANGA WEST
DAR ES SALAAM, UPANGA WEST
Tanzania

Junkun Ren

Geisel School of Medicine at Dartmouth ( email )

1 Rope Ferry Road
Hanover, NH 03755-1404
United States

Catherine C. Rieke

Geisel School of Medicine at Dartmouth ( email )

1 Rope Ferry Road
Hanover, NH 03755-1404
United States

Dartmouth College - Dartmouth-Hitchcock Medical Center ( email )

Hanover, NH 03755
United States

Albert K. Magohe

Muhimbili University of Health and Allied Sciences ( email )

UPANGA WEST
DAR ES SALAAM, UPANGA WEST
Tanzania

Abigail M. Fellows

Geisel School of Medicine at Dartmouth ( email )

1 Rope Ferry Road
Hanover, NH 03755-1404
United States

Enat A. Arega

Dartmouth College - Dartmouth-Hitchcock Medical Center

Hanover, NH 03755
United States

Christopher E. Niemczak

Geisel School of Medicine at Dartmouth ( email )

1 Rope Ferry Road
Hanover, NH 03755-1404
United States

Brian P. Jackson

Dartmouth College ( email )

Department of Sociology
Hanover, NH 03755
United States

Margaret R. Karagas

Geisel School of Medicine at Dartmouth - Department of Epidemiology

Hanover, NH 03755
United States

Jay C. Buckey

Geisel School of Medicine at Dartmouth ( email )

1 Rope Ferry Road
Hanover, NH 03755-1404
United States

Dartmouth College - Dartmouth-Hitchcock Medical Center ( email )

Hanover, NH 03755
United States