OBJECTIVE: Visual hyperexcitability in the form of abnormal contrast gain control has been shown in @entity5516 and @entity3762 . We assessed the accuracy and reliability of measures of visual contrast gain control in discerning individuals with @entity3762 from healthy controls. METHODS: Twenty-four adult @entity1 with @entity3762 and 32 neurotypical control subjects from two study sites participated in a prospective, cross-sectional study. We recorded steady-state visual evoked potentials to a wide range of contrasts of a flickering grating stimulus. The resultant response magnitude vs. contrast curves were fitted to a standard model of contrast response function, and the model parameters were used as input features to a linear classifier to separate @entity1 from controls. Additionally we compared the relative contribution of model parameters towards the classification using a sparse feature-selection approach. RESULTS: Classification accuracy was 80% or better. Sensitivity and specificity both were 80-85%. Cross validation confirmed robust classifier performance generalizable across the data from the two samples. @entity1 ' relative lack of gain control at high contrasts was the most important information distinguishing @entity1 from controls. CONCLUSIONS: Individuals with @entity3762 were distinguishable from the neurotypical with a high degree of accuracy and reliability by a reduction in gain control at high contrasts. SIGNIFICANCE: Gain control is an essential neural operation that regulates neuronal sensitivity to stimuli and may represent a novel biomarker of hyperexcitability.

Altered visual contrast gain control is sensitive for XXXX .

@entity1 :: ('9606', 'Species') :: ['Patients', 'patients'] @entity3762 :: ('MESH:C562694', 'Disease') :: ['idiopathic generalized epilepsies', 'idiopathic generalized epilepsy'] @entity5516 :: ('MESH:D020195', 'Disease') :: ['photosensitive epilepsy']
@entity3762 :: (MESH:C562694,Disease) :: ['idiopathic generalized epilepsies']
