Language regression - two distinct phenotypes?

Isolated language regression may be a distinct phenotype to language regression with autistic regression rather than part of a continuum of the same disorder, according to the authors of a retrospective analysis.The authors describe the controversy over whether isolated language regression and language regression with autistic regression are two syndromes or just varying degrees of the same syndrome. They say, "In particular, there has been debate whether LR with AR, especially in those with epileptiform EEGs is part of the spectrum for 'Landau-Kleffner syndrome'." Their study analysed patient characteristics and EEGs of patients with isolated language regression and patients with language regression with autistic regression.The investigators analysed the records of 43 children with isolated language regression and 103 children with language regression with autistic regression who had overnight EEG monitoring. They found that there was a higher rate of clinical seizures in the children with isolated language regression compared to children with language regression (33% versus 8%). Epileptiform abnormalities, particularly focal epileptiform abnormalities, were also more common in isolated language regression (60% versus 31%). Other differences included the mean age at regression, which was higher in the isolated language regression group. The criteria for Landau-Kleffner syndrome (LKS) was met in none of the children who had language regression with autistic regression, but in 25 children with isolated language regression. Fifteen of these children had language regression and seizures, and 10 had language regression and an epileptiform EEG without a history of clinical seizures.The authors conclude that, while there is some overlap, isolated language regression and language regression with autistic regression are two distinct phenotypes with different EEG abnormalities. They say that careful phenotyping of children with language regression is needed in future studies to determine prognosis, electrophysiology, genetics and treatment response.Reference...