Heterogeneity In Cognitive Functioning Research Articles

Predictors of individual differences in minimally verbal peer communication exchanges following peer-oriented social intervention.

School-age children on the autism spectrum who are minimally verbal (MVAS) use a limited repertoire of spontaneous communicative spoken words and reveal large heterogeneity in cognitive functioning. Despite the challenges to form peer social engagement posed by their unique social-communicative profile, few interventions have targeted peer interactions in the MVAS population. This study explored predictors of individual differences in treatment response among 54 school-age minimally verbal autistic children (8-16 years) following an RCT "school-based peer social intervention" (S-PSI) that compared two peer-oriented intervention modalities (conversation versus collaboration) versus a waitlisted control group. We examined autistic-symptom severity, age, verbal and nonverbal IQ, executive functions, and sensory-processing profile for their contribution to children's ability to form relevant spontaneous communication exchanges with a peer partner. Main findings revealed that larger deficits in sensory-processing (sensory-avoidance and sensory low-registration) and in executive functions contributed to greater growth in "relevant" (i.e., adequately attuned, participatory, reciprocal) communication following both interventions, but not for the waitlisted controls. Additionally, older participants with lower verbal and nonverbal IQ improved communication's relevancy more after the conversation intervention, whereas the collaboration intervention was more beneficial for younger participants. Lower autistic-symptom severity contributed to larger growth in relevancy for all groups. By identifying individual-level predictors of spontaneous, attuned, participatory, and reciprocal (i.e., "relevant") communication exchanges with peers, we optimized S-PSI personalization for this uniquely nonverbal, heterogeneous MVAS population. These new channels for tailoring peer interventions to better meet individuals' needs may result in reduced social isolation and loneliness and enhanced well-being.

P169. Brain Age and Cognitive Functioning in First Episode Bipolar Disorder

Cognitive deficits are detectable from illness onset in bipolar I disorder (BDI). There is significant heterogeneity in cognitive functioning in this cohort, suggesting potential differences in underlying biological mechanisms. This study investigated whether accelerated or delayed age-related brain structural changes are associated with cognitive functioning in first episode BDI.

Quantifying the heterogeneity of cognitive functioning in Alzheimer's disease to extend the placebo-treatment dichotomy: Latent class analysis of individual-participant data from five pivotal randomized clinical trials of donepezil.

The extent and profiles of heterogeneity in cognitive functioning among participants in clinical trials of antidementia medication are unknown. We aimed to quantify and identify profiles of heterogeneity of cognition in Alzheimer's disease. Individual-level participant data were analyzed from five pivotal clinical trials of donepezil for Alzheimer's disease (N=2,919). Based on Alzheimer's Disease Assessment Scale-Cognitive Subscale total scores from baseline up to week 12, a latent class model was used to identify heterogeneous groups. A logistic regression model was used to examine factors associated with group membership. Sensitivity analysis was conducted, restricted to the donepezil, and then the placebo arm. The latent class model identified three classes labeled as low scorers (i.e., least cognitive impairment; N=1,666, 76.04%), improvers (N=27, 1.23%), and high scorers (N=498, 22.73%). Logistic modeling showed that donepezil compared to placebo was significantly (p<0.05) positively associated with membership in the improvers class (OR=6.88, 95% CI=2.03, 42.95), and negatively with high scorers (OR=0.79, 95% CI=0.64, 0.98). Sensitivity analysis restricted to the placebo, then donepezil arms replicated similar heterogeneity patterns. Our results inform clinicians regarding the extent of heterogeneity in cognitive functioning during treatment and contribute to trial design considerations.

Dealing with heterogeneity of cognitive dysfunction in acute depression: a clustering approach.

Heterogeneity in cognitive functioning among major depressive disorder (MDD) patients could have been the reason for the small-to-moderate differences reported so far when it is compared to other psychiatric conditions or to healthy controls. Additionally, most of these studies did not take into account clinical and sociodemographic characteristics that could have played a relevant role in cognitive variability. This study aims to identify empirical clusters based on cognitive, clinical and sociodemographic variables in a sample of acute MDD patients. In a sample of 174 patients with an acute depressive episode, a two-step clustering analysis was applied considering potentially relevant cognitive, clinical and sociodemographic variables as indicators for grouping. Treatment resistance was the most important factor for clustering, closely followed by cognitive performance. Three empirical subgroups were obtained: cluster 1 was characterized by a sample of non-resistant patients with preserved cognitive functioning (n = 68, 39%); cluster 2 was formed by treatment-resistant patients with selective cognitive deficits (n = 66, 38%) and cluster 3 consisted of resistant (n = 23, 58%) and non-resistant (n = 17, 42%) acute patients with significant deficits in all neurocognitive domains (n = 40, 23%). The findings provide evidence upon the existence of cognitive heterogeneity across patients in an acute depressive episode. Therefore, assessing cognition becomes an evident necessity for all patients diagnosed with MDD, and although treatment resistant is associated with greater cognitive dysfunction, non-resistant patients can also show significant cognitive deficits. By targeting not only mood but also cognition, patients are more likely to achieve full recovery and prevent new relapses.

T86. COGNITIVE SUBTYPES IN FIRST-EPISODE PSYCHOSIS: AN EMPIRICAL LONGITUDINAL STUDY OF RELATIONSHIP TO COGNITIVE, SYMPTOM AND FUNCTIONAL OUTCOMES

BackgroundVariable outcomes following a first-episode of psychosis are partly attributable to heterogeneity in cognitive functioning. Previous work in first episode psychosis has identified clinically meaningful cognitive sub-types based on pre-specified differences in estimated premorbid and current cognitive functioning. We used an empirical clustering technique to examine whether these cognitive profiles can be replicated with an unbiased method, their relationship with clinical, cognitive and global functioning at psychosis onset as well as their stability over time.MethodsPatients attending NHS early intervention services following a first episode of psychosis were recruited to a double-blind clinical trial of minocycline for negative symptoms of psychosis (BeneMin) which found no treatment effect. Participants were assessed on clinical, cognitive and global functioning at baseline (n=169) and 12-month follow-up (n=107). K-means analysis was used to empirically cluster participants on the basis of estimated premorbid IQ (WTAR), and baseline cognitive functioning (derived from 4 sub-tests of the WAIS IV, verbal fluency (COWAT) and verbal learning scores (AVLT)). Clinical and global functioning was assessed using the Positive and Negative Syndrome Scale (PANSS), Calgary Depression Scale (CDS) and Global Assessment of Functioning (GAF).ResultsK-means cluster analysis revealed three cognitive subgroups: 28% showing preserved premorbid and current IQ (PIQ); 29% displaying compromised premorbid and current IQ (CIQ); and 43% with normal premorbid but deteriorated current IQ (DIQ). There were no significant differences between groups in age, gender, CDS, cannabis use or olanzapine equivalent antipsychotic dose. The PIQ group performed significantly better than the DIQ group on all baseline cognitive measures, who performed significantly better than the CIQ group. At baseline, there were significant differences in GAF scores (F(2,168) = 4.267, p=0.016; PIQ >DIQ, LIQ). At 12-months, all three groups had improved over time on cognitive function with no group x time interactions except verbal fluency (F(2, 97) = 5.204,p=0.007) where only the DIQ group improved. All groups improved on positive and total symptom scores but only the PIQ and DIQ groups significantly improved on negative and general symptom scales. There was no significant change in GAF score in any of the groups over time. At follow-up there were significant differences between groups in negative syndrome scores (F(2, 104) = 8.720, p=0.004: LIQ > PIQ, DIQ) and global functioning (F(2,101) = 5.880 p=0.004; PIQ > DIQ, LIQ).DiscussionUsing an unbiased method to define cognitive subgroups at first episode, we confirmed in a new sample, previous findings which used pre-specified criteria. A large subgroup showed evidence of a decline in IQ at psychosis onset and 12-months later this subgroup had neither continued to deteriorate nor returned to premorbid levels of cognition. Patients with preserved normal and compromised cognitive function at psychosis onset showed no deterioration over 12 months. The cognitive sub-groupings were clinically meaningful. The preserved group showed better general function which persisted over 12 months. General functional outcome in the IQ decline group was as poor as the compromised group and the compromised group had more persistent negative symptoms.

Classification of cognitive performance in bipolar disorder

ABSTRACTObjective: To understand the etiology of cognitive impairment associated with bipolar disorder, we need to clarify potential heterogeneity in cognitive functioning. To this end, we used multivariate techniques to study if the correlation structure of cognitive abilities differs between persons with bipolar disorder and controls.Method: Clinically stable patients with bipolar disorder (type I: n = 64; type II: n = 44) and healthy controls (n = 86) were assessed with a wide range of cognitive tests measuring executive function, speed, memory, and verbal skills. Data were analysed with multivariate techniques.Results: A distinct subgroup (∼30%) could be identified that performed significantly poorer on tests concerning memory function. This cognitive phenotype subgroup did not differ from the majority of bipolar disorder patients with respect to other demographic or clinical characteristics.Conclusions: Whereas the majority of patients performed similar to controls, a subgroup of patients with bipolar disorder differed substantially from healthy controls in the correlation pattern of low-level cognitive abilities. This suggests that cognitive impairment is not a general trait in bipolar disorder but characteristic of a cognitive subgroup. This has important clinical implications for cognitive rehabilitation and remediation.

Exploring cognitive heterogeneity in first-episode psychosis: What cluster analysis can reveal

Variable outcomes in first-episode psychosis (FEP) are partly attributable to heterogeneity in cognitive functioning. To aid identification of those likely to have poorer or better outcomes, we examined whether purported cognitive profiles identified through use of cluster analysis in chronic schizophrenia were evident in FEP. We also aimed to assess whether there was a relationship between cognitive profile and factors independent of the solution, providing external validation that the cognitive profiles represented distinct subgroups. Ward's method hierarchical cluster analysis, verified by a k-means cluster solution, was performed using data obtained from a cognitive test battery administered to 128 participants aged 15–25 years. Four cognitive profiles were identified. A continuity element was evident; participants in cluster four were more cognitively impaired compared to participants in cluster three, who appeared more cognitively intact. Clusters one and two were distinguishable across measures of attention and working memory and visual recognition memory, most likely reflecting sample specific patterns of deficit. Participants in cluster four had significantly lower premorbid and current IQ and higher negative symptoms compared to participants in cluster three. The distinct levels and patterns of cognition found in chronic schizophrenia cohorts are also evident across diagnostic categories in FEP.

Heterogeneity in cognitive functioning among patients with bipolar disorder

Background Nowadays it is not clear if in bipolar disorders (BD) cognitive impairments are heterogeneous and if so which are the variables that determine it. Methods Fifty patients with BD and thirty healthy controls were clinically evaluated including measures of obstetric complications history. All subjects completed an extensive neuropsychological battery selected to asses premorbid IQ and different cognitive domains. Results Compared with standardized norms, 38% of patients had none cognitive domain affected, while 40% had 1 to 2, and 22% had 3 to 5. Patients with cognitive functioning within normal limits had higher psychosocial functioning and premorbid IQ, and lower history of obstetric complications. Limitations The small sample size could limit the generalizability of the results; since these data should be taken as preliminaries. Conclusions The extension and severity of cognitive impairments may be heterogeneous in patients with BD, and it might contribute to explain the variability in functional outcome. Bipolar patients with low premorbid IQ and history of obstetric complications may represent a subgroup with lower cognitive performance and psychosocial functioning.

Heterogeneity in cognitive functioning of schizophrenic patients evaluated by a lexical decision task.

The disorganization pattern in schizophrenia, which involves formal thought disorders, is thought to be correlated with a deficit in integrative processes of contextual information. We tested the hypothesis that thought disordered schizophrenics, unlike non-though disordered schizophrenics, would present a deficit in the processing of the context during a task which involves these integrative processes. A group of 22 schizophrenic patients diagnosed in accordance with DSM-III-R criteria and a group of 11 control subjects were compared using a semantic priming version of the lexical decision task. The experimental design used low-level structuration of verbal material to reveal the difficulty that schizophrenic patients encounter in using semantic regularities. A significant difference in priming effect was found between the three groups. Control subjects and non-thought disordered schizophrenics exhibit a priming effect for related word pairs when compared with unrelated pairs (respectively F(1,10) = 17.7; P < 0.002 and f(1,10) = 14.5; P > 0.003) but thought disordered schizophrenics did not (F(1,10) < 1; NS). This finding provides evidence for the cognitive heterogeneity of schizophrenic subjects. This absence of priming effect in thought-disordered schizophrenic subjects supports the hypothesis that these patients present a deficit in the post-lexical controlled information processing that permits the integration of semantic information.