Cognitive evaluation of patients with chronic neurolathyrism.

Objective: The object of the present study was to evaluate whether patients with neurolathyrism (NL) have cognitive abnormalities, and whether the cognitive decline, if found, correlates with the motor deficit.

Background: NL is a neurological syndrome that develops following ingestion of the grass pea (Lathyrus Sativus). These beans have excellent nutritional properties but contain the neurotoxin beta-N-oxalylamino-l-alanine (BOAA), suggested to be responsible for the development of CNL with the main symptom being spastic paraparesis. BOAA is closely related to beta-metyl-amino-alanine (BMA), the putatove phytotoxin involved in the pathogenesis of the ALS-PD complex of Guam. As the latter includes dementia, we investigated the cognitive functions of CNL patients.

Methods: NL patients (n=30), all subjects over 65-years old, and 30 aged matched controls underwent a neurological examination including a structured cognitive evaluation diagnosed according to DSM-IV criteria. In addition, all the participants were tested with the Wechsler Memory Scale (WMS). Patients' motor function was divided into five stages according to disease severity. Statistical analysis was performed using Student's t-test.

Results: Only one patient was found to be demented. The 30 CNL patients had a mean total WMS score of 57.2+/-18.2 and a memory quotient (MQ) of 128.9+/-28.5. The corresponding values for controls were 57.1+/-13.2 and 124+/-15.2 and there were no significant statistical differences between the two groups. No correlation was found between the cognitive and motor state of the CNL patients.

Conclusion: The cognitive state of CNL patients does not show a decline.