Abstracts

Rationale: Juvenile Neuronal Ceroid Lipofuscinosis (JNCL) is the most common neurodegenerative disorder in childhood with survival until young adult age. Visual loss is followed by epilepsy, cognitive, neuropsychiatric and motor symptoms. We have studied the evolution of EEG and seizure characteristics. Methods: 24 patients were recruited via the Norwegian JNCL parent association. Parents were interviewed. Medical records and EEG reports/recordings were collected.  EEG elements were classified according to SCORE; their evolution was assessed by testing difference in proportions with standardized normal deviate comparing EEG abnormality prevalences below and above 15 years of age. Results: Mean age at study or death (n=10) was 21 (10-38) years. 22 patients had experienced seizures; the first was usually bilateral tonic-clonic (TC). Later, focal motor seizures frequently occurred, often with increasing multifocal and polymorphic features. In patients followed to terminal stage, serial focal motor seizures as well as status epilepticus were common. Distinct myoclonic seizures were rare. In three patients, episodes of bradycardia/sinus arrest were identified.EEG showed progressive slowing of the background activity (p=0.029). Focal epileptiform discharges were rare and mainly seen at age <10. Multifocal and generalized/bilateral epileptiform discharges increased in adolescence (p=0.003). Conclusions: Seizure and EEG characteristics change with time in JNCL. TC are common at onset, and multifocal motor seizures increase with age. In contrast, focal epileptiform abnormalities are more common in childhood, compared to later multifocal and bilateral discharges. This seizure disorder belongs to the Combined Generalized and Focal Epilepsies. Uncommon myoclonic seizures preclude apt classification as a Progressive Myoclonic Epilepsy; this may have impact on treatment choice. When attacks with only behavior arrest occur, cardiac conduction abnormalities should be considered.  Funding: None