Exploratory Factor Analysis of the WAIS-III Thai Version in Patients with Mild Cognitive Impairment

Objective: To investigate the generalizability of the Wechsler Adult Intelligence Scale-III (WAIS-III) factors structure in a sample of mild cognitive impairment (MCI) patients. Materials and Methods: A retrospective study of patients older than 60 years receiving treatments at the Memory Clinic in Ramathibodi Hospital between January 2015 and July 2018 was conducted. The WAIS-III Thai version was used to measure the performance. All subtests except the Vocabulary and Object Assembly subtests were included for analyses. These 12 subtests were subjected to a principal axis factor analysis with oblique rotation and four factors were specified to be retained. Results: Out of 145 patients, 51% were female and 49%were male. The Full-Scale IQ ranged from 80 to 123 with the mean of 93.88 (SD 9.12). The mean of each subtest ranged from 7.82 (Similarities) to 10.45 (Digit Span), with the standard deviations ranging from 1.80 to 2.86. Based on the order of extraction and minimum loading criterion, results supported a four-factor solution composed of Verbal Comprehension, Perceptual Organization, Working Memory, and Processing Speed. The coefficients of congruence across groups on the four factors ranged from 0.92 for Perceptual Organization to 0.73 for Processing Speed. However, the Picture Completion subtest was found to have similar loadings between Perceptual Organization and Processing Speed, with the primary loading being on Perceptual Organization and secondary loading on Processing Speed. On the Working Memory factor, the MCI group showed areas of relatively greater divergence for Picture Arrangement, Block Design, and Digit Symbol: Coding subtests. Conclusion: Four factors from WAIS-III could be applied to patients with MCI. The decline of cognitive functions, particular in working memory, might be the explanation for the difference in loading factor among some subtests. Therefore, it might be possible to apply other models with other factors to the same patient group in the future. Keywords: Mild cognitive impairments; Exploratory factor analysis; WAIS-III

ADGRL3, FGF1 and DRD4: Linkage and Association with Working Memory and Perceptual Organization Candidate Endophenotypes in ADHD

Attention deficit hyperactivity disorder (ADHD) is a highly heritable neurobehavioral disorder that affects children worldwide, with detrimental long-term consequences in affected individuals. ADHD-affected patients display visual–motor and visuospatial abilities and skills that depart from those exhibited by non-affected individuals and struggle with perceptual organization, which might partially explain impulsive responses. Endophenotypes (quantifiable or dimensional constructs that are closely related to the root cause of the disease) might provide a more powerful and objective framework for dissecting the underlying neurobiology of ADHD than that of categories offered by the syndromic classification. In here, we explore the potential presence of the linkage and association of single-nucleotide polymorphisms (SNPs), harbored in genes implicated in the etiology of ADHD (ADGRL3, DRD4, and FGF1), with cognitive endophenotypes related to working memory and perceptual organization in 113 nuclear families. These families were ascertained from a geographical area of the Caribbean coast, in the north of Colombia, where the community is characterized by its ethnic diversity and differential gene pool. We found a significant association and linkage of markers ADGRL3-rs1565902, DRD4-rs916457 and FGF1-rs2282794 to neuropsychological tasks outlining working memory and perceptual organization such as performance in the digits forward and backward, arithmetic, similarities, the completion of figures and the assembly of objects. Our results provide strong support to understand ADHD as a combination of working memory and perceptual organization deficits and highlight the importance of the genetic background shaping the neurobiology, clinical complexity, and physiopathology of ADHD. Further, this study supplements new information regarding an ethnically diverse community with a vast African American contribution, where ADHD studies are scarce.

Locomotor illusions are generated by perceptual body-environment organization

While one is walking, the stimulation by one’s body forms a structure with the stimulation by the environment. This locomotor array of stimulation corresponds to the human-environment relation that one’s body forms with the environment it is moving through. Thus, the perceptual experience of walking may arise from such a locomotor array of stimulation. Humans can also experience walking while they are sitting. In this case, there is no stimulation by one’s walking body. Hence, one can experience walking although a basic component of a locomotor array of stimulation is missing. This may be facilitated by perception organizing the sensory input about one’s body and environment into a perceptual structure that corresponds to a locomotor array of stimulation. We examined whether locomotor illusions are generated by this perceptual formation of a locomotor structure. We exposed sixteen seated individuals to environmental stimuli that elicited either the perceptual formation of a locomotor structure or that of a control structure. The study participants experienced distinct locomotor illusions when they were presented with environmental stimuli that elicited the perceptual formation of a locomotor structure. They did not experience distinct locomotor illusions when the stimuli instead elicited the perceptual formation of the control structure. These findings suggest that locomotor illusions are generated by the perceptual organization of sensory input about one’s body and environment into a locomotor structure. This perceptual body-environment organization elucidates why seated human individuals experience the sensation of walking without any proprioceptive or kinaesthetic stimulation.

The effect of perceptual organization on risky choice and numerical decisions shows inter-subject correlation

Individual differences in cognitive processing have been the subject of intensive research. An important type of such individual differences is the tendency for global vs. local processing, which was shown to correlate with a wide range of processing differences in fields such as decision making, social judgments and creativity. Yet, whether these global/local processing tendencies are correlated within a subject across different domains is still an open question. To address this question, we develop and test a novel method to quantify global/local processing tendencies, in which we directly set in opposition the local and global information instead of instructing subjects to specifically attend to one processing level. We apply our novel method to two different domains: i) a numerical cognition task, and ii) a preference task. Using computational models, we accounted for classical effects in choice and numerical-cognition. Global/local tendencies in both tasks were quantified using a salience parameter. Critically, the salience parameters extracted from the numerical cognition and preference tasks were highly correlated, providing support for robust perceptual organization tendencies within an individual.