Using advanced imaging methods to study neurolathyrism

Background: Neurolathyrism is a toxic nutritional disorder caused by consumption of the grass pea, Lathyrus sativus. The disease, which manifests as an acute or insidiously evolving spastic paraparesis, continues to occur throughout Africa and Asia. Research on this disease is limited, and to our knowledge no imaging studies of patients with neurolathyrism have been published. Objectives: To better localize the site of damage in neurolathyrism using advanced imaging methods. Methods: Three male patients, immigrants from Ethiopia, were included in the study. All had a history of arrested spastic paraparesis that had evolved before their emigration from Ethiopia, and a past history of exposure to grass pea without any other cause. Functional magnetic resonance imaging (fMRI) included simple motor tasks to evaluate cortical motor areas. Anatomic scans included diffusion tensor imaging (DTI) to evaluate the corticospinal tracts. Results: In all patients clear activation was found in motor regions, and the patients’ activity pattern was qualitatively similar to that in control subjects. In one patient in whom clinical symptoms were asymmetric, an asymmetric activity pattern in M1 was identified. DTI analysis identified intact corticospinal tracts connecting the pons and the primary motor regions, similar to control subjects. Conclusions: Advanced neuroimaging clearly identified wellfunctioning motor regions and tracts in neurolathyrism patients, suggesting a spinal etiology.