PUBLICATIONS (WITH LINKS):

Renteria-Vazquez, T., Brown, W.S., Kang, C., Graves, M., Castelli, F. and Paul, L.K. (2021) “Social Inferences in Agenesis of the Corpus Callosum and Autism: Semantic Analysis and Topic Modeling”. Journal of Autism and Developmental Disorders. https://doi.org/10.1007/s10803-021-04957-2

Impoverished capacity for social inference is one of several symptoms that are common to both agenesis of the corpus callosum (AgCC) and Autism Spectrum Disorder (ASD). This research compared the ability of 14 adults with AgCC, 13 high-functioning adults with ASD and 14 neurotypical controls to attribute social meaning to the interactions of animated triangles. Descriptions of the animations were analyzed in three ways: subjective ratings, topic modeling (Latent Dirichlet Allocation), and Linguistic Inquiry and Word Count. Although subjective ratings indicated that all groups made similar inferences from the animations, the index of perplexity (atypicality of topic) generated from topic modeling revealed that inferences from individuals with AgCC or ASD displayed significantly less social imagination than those of controls.

Su, J., Paul , L.K., Graves, M., Turner, J.M., and Brown, W.S. (2023) “Verbal Problem Solving in Agenesis of the Corpus Callosum: Analysis Using Semantic Similarity”, Neuropsychology, https://doi.org/10.1037/neu0000894

This study investigated verbal problem-solving, deductive reasoning, and semantic inference in AgCC. Capacity for semantic inference was tested in 25 individuals with AgCC and normal-range intelligence and compared to 29 neurotypical controls. The Word Context Test (WCT) of Delis-Kaplan Executive Function System was used, employing a novel method of analysis (semantic similarity) to detect trial-by-trial progress toward a solution. Persons with AgCC had fewer total consecutive correct responses. In addition, semantic similarity to the correct word was significantly lower overall in persons with AgCC than in controls. These findings indicated that individuals with AgCC who have intelligence in the normal range are less able to make semantic inferences on the WCT, although they often solve the problem eventually. This outcome suggests that callosal absence in AgCC results in a restricted imagination for possibilities, limiting their semantic problem-solving and inferential capacities.

Paul, L. K., Pazienza, S., and Brown, W. S. (2021) “Alexithymia and somatization in agenesis of the corpus callosum.” Social Cognitive and Affective Neuroscience. doi: 10.1093/scan/nsab056

This study compared self-reported alexithymia and somatic symptoms from 19 adults with ACC and FSIQ > 80 with 16 age and IQ-matched neurotypical controls. The ACC group had higher scores on the Toronto Alexithymia Scale (p < .01), specifically reporting greater difficulty identifying and describing feelings (p < .003 and .05, respectively).  In addition, persons with ACC endorsed more physical symptoms on somatization scale of the Symptom Checklist-90-R (p < .01), and were more likely than controls to attribute physical symptoms to psychological factors (p < 05), indicating the presence of alexithymia with somatization. Nevertheless, persons with ACC reported similar levels of emotional experience as controls. Thus, reduced interhemispheric connectivity in ACC appears to contribute to difficulty identifying emotions and the tendency to somaticize, but it does not limit emotional experience.

Mangum, R.W, Miller, J.S., Brown, W.S., Nolte, A., & Paul, L.K. (2021) “Daily Executive Function in Agenesis of the Corpus Callosum.” Journal of the International Neuropsychology Society. doi:10.1017/S1355617721000096 

This study investigated daily executive functioning and self-awareness in 36 individuals with ACC by analyzing self- and observer-ratings on the Behavior Rating Inventory of Executive Functioning-Adult Version (BRIEF-A). Significant deficiencies were found in both the Behavioral Regulation and Metacognitive indices for both the self and observer results. Generally, scores were higher (greater deficiency) in observer ratings, with metacognitive functioning rated significantly more deficient by observers than by the persons with ACC. These findings provide evidence for mild executive functioning problems in the everyday behavior of individuals with ACC.  Results also suggest a lack of self-understanding or insight into the severity of these problems in the individuals with ACC, particularly with respect to their metacognitive functioning. 

Renteria-Vazquez, T., Brown, W.S., Kang, C., Graves, M., Castelli, F. and Paul, L.K. (2021) “Social Inferences in Agenesis of the Corpus Callosum and Autism: Semantic Analysis and Topic Modeling”. Journal of Autism and Developmental Disorders. doi.org/10.1007/s10803-021-04957-2 

Impoverished capacity for social inference is one of several symptoms that are common to both agenesis of the corpus callosum (AgCC) and Autism Spectrum Disorder (ASD).  This research compared the ability of 14 adults with AgCC, 13 high-functioning adults with ASD and 14 neurotypical controls to attribute social meaning to the interactions of animated triangles.  Descriptions of the animations were analyzed in three ways: subjective ratings, topic modeling (Latent Dirichlet Allocation), and Linguistic Inquiry and Word Count. Although subjective ratings indicated that all groups made similar inferences from the animations, the index of perplexity (atypicality of topic) generated from topic modeling revealed that inferences from individuals with AgCC or ASD displayed significantly less social imagination and elaborative content than those of controls.

Brown, W.S., Panos, A. and Paul, L.K. (2020) “Impulsivity, Vigilance and Attention in Agenesis of the Corpus Callosum” Neuropsychology. doi.org/10.1037/neu0000685 

This study assessed inattention, impulsivity, and vigilance in individuals with AgCC. These domains of attention were assessed using the Connor’s Continuous Performance Test, Second Edition (CPT II) in 18 older adolescents and adults (ages 16-52) with complete AgCC and normal intelligence (FSIQ > 80). Scores were significantly elevated in older adolescents with AgCC for errors of commission and detectability. Older adolescents were worse than adults for commissions and detectability. Also, males had significantly higher (worse) scores than females in Vigilance. These results suggest moderate levels of difficulties in sustained attention in AgCC, particularly in maintaining response inhibition and in vigilance, that are modulated by age and sex.

Paradiso, S., Brown, W.S., Porcerelli, J.H., Tranel, D., Adolphs, R., & Paul, L.K. (2020) “Integration Between Cerebral Hemispheres Contributes to Defense Mechanisms.” Frontiers Psychology. doi:10.3389/fpsyg.2020.01534 

This study tests the role of information integration in the development of defense mechanisms by quantifying such mechanisms in people with AgCC. Individuals with AgCC (N=30) and healthy volunteers (N=30, sex, age and FSIQ matched) were compared on defense mechanisms across increasing levels of developmental maturity (Denial, least mature; Projection, intermediate; Identification, most mature).  The primary dependent measure was derived from narratives generated by participants in response to Thematic Apperception Test cards (TAT). Compared to controls, participants with AgCC showed significantly greater Denial (p=0.026) and less Identification (p<0.0001), effects not attributable to either full-scale or verbal IQ. This finding supports the hypothesis that functional integration across the hemispheres is important for the development of defenses.

Brown, W.S., Burnett, K., Vaillancourt, A., & Paul, L.K.  (2020) “Appreciation of Social Norms in Agenesis of the Corpus Callosum.” Archives of Clinical Neuropsychology. doi:10.1093/arclin/acab003 

We attempted to determine whether adults with AgCC are able to correctly identify appropriate behaviors within social contexts using online administration of the Social Norms Questionnaire. The Social Norms Questionnaire measures knowledge of norms and judgments of what is appropriate to do in particular contexts. Individuals with AgCC scored significantly lower in understanding social norms than controls, tending to over-adhere to social norms significantly more than controls. There was no significant difference regarding breaking of social norms. Results suggest that adults with AgCC have deficient knowledge of, and judgment regarding, the nuances of appropriate behaviors in social contexts. They may know social norms concretely, yet lack the ability to integrate context in specific scenarios to make appropriate judgments. 

Brown, W. S. & Paul, L. K. (2019). The neuropsychological syndrome of agenesis of the corpus callosum. Journal of the International Neuropsychological Society. 1-7. doi: https://doi.org/10.1017/S135561771800111X

This paper describes the core deficits in persons with ACC. The cores syndrome includes: (1) Reduced interhemispheric transfer of sensory-motor information; (2) Reduced cognitive processing speed; and (3) Deficits in complex reasoning and novel problem-solving. As a consequence of these core deficiencies, individuals with ACC have difficulty across various domains of cognitive, behavior, and social functioning.