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Your Environment. Your Health.

Continued Motor and Cognitive Impairment from Poorly Processed Cassava

Desire Tshala-Katumbay, M.D., Ph.D.
Oregon Health and Science University

NIEHS-funded researchers and colleagues showed that exposure to poorly processed cassava was linked to impaired motor and cognitive performance in children, especially boys, over time. By measuring a marker in urine, the researchers were able to identify children at risk for neurological impairment before they exhibited clear clinical symptoms.

Cassava, which is a subsistence crop for more than 600 million people around the world, can contain cyanide if not properly detoxified by methods such as soaking with water and then drying in the sun. Consumption of improperly prepared cassava is associated with neurological conditions, including konzo, a disorder that can lead to irreversible paralysis of the legs.

The researchers assessed cognitive and motor performance in children with and without konzo in the town of Kahemba, Congo. They also measured levels of thiocyanate, a marker of recent cyanide exposure, in the children’s urine.

They showed that children with konzo had impaired motor skills at least 4 years after konzo diagnosis, and that boys without konzo performed better on cognitive tests than boys with konzo. They also found an association between reduced motor proficiency and increased levels of urinary thiocyanate in boys with and without konzo, but not in girls. By measuring this specific marker in urine, the researchers documented that boys not diagnosed with konzo may be on the threshold of neuropsychological impairment, possibly because of ongoing exposure to poorly processed cassava.

According to the authors, the urinary thiocyanate indicator could be used with community-wide, household-based health education to identify children at risk for neurodevelopmental disabilities and to reduce their exposure.

Citation: Boivin MJ, Okitundu D, Makila-Mabe B, Sombo MT, Mumba D, Sikorskii A, Mayambu B, Tshala-Katumbay D. 2017. Cognitive and motor performance in Congolese children with konzo during 4 years of follow-up: a longitudinal analysis. Lancet Glob Health. 5(9):e936–e947.

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