Objectives: To reconsider the mentioned association between epilepsy and/or EEG abnormalities with clinical, biological, developmental and familial medical history. We examined data extracted from two different large and selected samples of ASD patients.
Methods: We analyzed two different samples of non syndromic ASD patients: an original sample encompassing 432 Italian patients and a replica sample including 714 Caucasian American patients recruited by the Autism Genetic Resource Exchange Consortium (AGRE). Comparable clinical, biological and developmental variables were correlated in both samples with “presence/absence of epilepsy” or “presence/absence of EEG abnormalities”, and tested for association between each variable and biological endophenotypes (serotonin blood levels, head circumference and global peptiduria), by non parametric Kendall τ, Kruskal-Wallis ANOVA and Mann-Whitney U test.
Results: In the experimental sample and in the replica sample, ASD patients positive for EEG abnormalities display a significant association with a lower risk of familial history for autoimmune/allergic diseases (Italian and AGRE sample: τ= -0.115 and -0.252, respectively; both P<0.05), and those affected by epilepsy are characterized specifically by verbal language delay in the absence of a generalized neurodevelopmental delay (Italian and AGRE sample: τ= 0.100 and 0.073; both p<0.05). Interestingly, Italian patients with EEG abnormalities show significantly lower serotonin blood levels (τ=-0.183; P<0.01).
Overall, epilepsy and EEG abnormalities remain a relatively isolated and independent features, not strongly associated with specific symptom patterns. Nonetheless, these results extend previous findings, by supporting a deleterious effect of EEG abnormalities on verbal language development, and by pointing toward a protective role against the development of epilepsy for a family history of autoimmune/allergic diseases and elevated serotonin blood levels. These results spur interest into the potential positive effects of antiepileptic drug treatment in facilitating language development among small non-verbal ASD children with EEG abnormalities, even in the absence of overt seizures.
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