Landau Kleffner Syndrome: An Unusual Case With Progressive Ataxia Prior To Language Regression And Autistic-Like Behaviors

Objective To report a case with Landau-Kleffner syndrome (LKS) presenting with unusual clinical features. Methods The clinical features of the case including clinical manifestations, serial electroencephalography (EEG) outcomes, neuroimaging findings, neuropsychological outcomes, interventional approaches and long-term follow-up outcomes, were analyzed. Results This previously normal girl (3y10m), presented with progressive ataxia as an onset symptom, ensued with cognitive impairments and language regressions (characterized by verbal auditory agnosia and expressive aphasia), and autistic-like behaviors. She had no evidence of clinical seizures, with normal brain and spine MRI scans, intact auditory exams and normal brain auditory evoked potential, although the sleep- activated inter-ictal epileptiform discharges of EEG were revealed. The patient showed gradual resolution of symptoms with long-term high-dose steroids plus intravenous immunoglobulin (IVIG) regimens, in consistence with the gradual improvement of the outcomes of serial EEGs. She recovered and returned to normal kindergarten 1y1m after the onset of the disease, consistent with the normal EEG results. Her full-scale intelligence quotient (IQ) was 71 score, with verbal IQ 66 and performance IQ 81 respectively, tested at the time of 1y3m after the onset. The long-term prognosis of the case was good as she had good academic performance and was a monitor of the class at the time of her long-term follow-up of 5y8m after the onset. Conclusion LKS is heterogeneity entity, especially for those with the atypical onset such as ataxia, as well as absence of clinical seizures. The combination of long-term high-dose steroid plus IVIG regimens may be especially effective in LKS.