Visual processing deficits in 22q11.2 Deletion Syndrome

• Published in: NeuroImage clinical Vol. 17; pp. 976 - 986
• Main Authors: Biria, Marjan, Tomescu, Miralena I., Custo, Anna, Cantonas, Lucia M., Song, Kun-Wei, Schneider, Maude, Murray, Micah M., Eliez, Stephan, Michel, Christoph M., Rihs, Tonia A.
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier Inc 01.01.2018; Elsevier
• Subjects: 22q11.2 Deletion Syndrome; Adolescent; Adult; Analysis of Variance; Biomarkers; Brain Mapping; Correlation of Data; DiGeorge Syndrome - complications; Electroencephalography; Evoked Potentials, Visual - physiology; Female; High-density EEG; Humans; Illusory contours; Male; Photic Stimulation; Prodromal Symptoms; Reaction Time - physiology; Regular; Schizophrenia; Severity of Illness Index; Time Factors; Vision Disorders - diagnosis; Vision Disorders - etiology; Visual Perception - physiology; Young Adult; Illusory contours; Schizophrenia; Biomarkers; High-density EEG; Prodromal symptoms; 22q11.2 Deletion Syndrome
• ISSN: 2213-1582; 2213-1582
• DOI: 10.1016/j.nicl.2017.12.028

Carriers of the rare 22q11.2 microdeletion present with a high percentage of positive and negative symptoms and a high genetic risk for schizophrenia. Visual processing impairments have been characterized in schizophrenia, but less so in 22q11.2 Deletion Syndrome (DS). Here, we focus on visual processing using high-density EEG and source imaging in 22q11.2DS participants (N=25) and healthy controls (N=26) with an illusory contour discrimination task. Significant differences between groups emerged at early and late stages of visual processing. In 22q11.2DS, we first observed reduced amplitudes over occipital channels and reduced source activations within dorsal and ventral visual stream areas during the P1 (100–125ms) and within ventral visual cortex during the N1 (150–170ms) visual evoked components. During a later window implicated in visual completion (240–285ms), we observed an increase in global amplitudes in 22q11.2DS. The increased surface amplitudes for illusory contours at this window were inversely correlated with positive subscales of prodromal symptoms in 22q11.2DS. The reduced activity of ventral and dorsal visual areas during early stages points to an impairment in visual processing seen both in schizophrenia and 22q11.2DS. During intervals related to perceptual closure, the inverse correlation of high amplitudes with positive symptoms suggests that participants with 22q11.2DS who show an increased brain response to illusory contours during the relevant window for contour processing have less psychotic symptoms and might thus be at a reduced prodromal risk for schizophrenia. •In schizophrenia, early visual processing is altered.•22q11.2DS carriers have an increased risk for schizophrenia.•Hd-EEG to investigate visual processing in an illusory contour task in 22q11.2DS.•Occipital cortex activity is reduced in 22q11.2DS early in time.•Both in 22q11.2DS and schizophrenia, early visual processing is impaired at P1.