<p>Cognitive impairments in schizophrenia (SZ) include
abnormalities in executive function, attention, and semantic processing. Event-related
potentials (ERPs) are used as neurophysiological measures of cognitive
impairment that have been shown to map onto symptom dimensions of psychotic
disorders, such as schizophrenia. While much research exists on schizophrenia, less
is understood about the longitudinal relationships between ERPs and symptom
dimensions among individuals at risk for psychosis. Of published work in risk
samples, most have been cross-sectional, leaving clinical inferences regarding
longitudinal patterns non-specific. The current study aimed to bridge this gap
by recording ERPs (P300, ERN, N400) across a battery of tasks within a single
risk sample, and measured positive, negative, and disorganized symptom severity
via the Multidimensional Schizotypy Scale (MSS). Participants exhibiting
psychosis-risk were recruited from the community (N=60), and completed a
baseline and 6-month follow-up assessment (n=29). The primary goal of the
baseline assessment aimed to replicate ERP-symptom dimension relationships
observed in the SZ literature. Effect sizes for P300-positive and ERN-negative
relationships were observed to be in the same directionality as noted in the
clinical SZ literature. While not statistically significant, the small effects
suggest that P300 and ERN may be similarly effected by presence of positive and
negative symptoms, respectively. By contrast, N400, however, was found to have
an effect size directionality opposite to that reported in the literature. This
finding is consistent with mixed presentation of disorganized symptoms in
clinical SZ populations. The follow-up assessment aimed to examine the
relationship of symptom dimensions over time in a single at-risk sample, and
leveraged ERPs as potential prospective predictors of worsening of symptoms. As
expected, baseline symptoms prospectively predicted corresponding symptoms at
follow-up. However, only N400 amplitude at baseline correlated with
disorganized symptoms at follow-up, and no ERP prospectively predicted
corresponding symptom dimensions at follow-up. Overall, examining the
relationship between multiple ERPs and symptom dimensions in a single sample
and via a longitudinal design is a novel addition to the literature. Future
research will be necessary to clarify the use of ERPs as neural biomarkers to
identify and predict symptom severity over time, ultimately reducing
subjectivity in clinical diagnosis and treatment. </p>
| Identifer | oai:union.ndltd.org:purdue.edu/oai:figshare.com:article/15070308 |
| Date | 29 July 2021 |
| Creators | Keisha D Novak (11199078) |
| Source Sets | Purdue University |
| Detected Language | English |
| Type | Text, Thesis |
| Rights | CC BY 4.0 |
| Relation | https://figshare.com/articles/thesis/Investigating_Concurrent_and_Longitudinal_ERP-Symptom_Relationships_Among_Risk_for_Psychosis/15070308 |
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