Psychophysiological correlates of dissociation, handedness, and hemispheric lateralization

Cross-cultural adaptation, validity and reliability of Turkish version of the Waterloo Handedness and Footedness Questionnaire-Revised

This study investigated the validity and reliability of Turkish versions of the Waterloo Handedness and Footedness Questionnaire-Revised (WHQ-R and WFQ-R). Turkish versions of the WHQ-R and the WFQ-R, and other assessments (the Handedness Questionnaire and the Footedness Preference Test) were applied to 444 healthy participants aged between 18 and 65 years. The translation and cultural adaptation process of the WHQ-R and the WFQ-R was provided by the following proposed guideline. For test-retest reliability, translated versions were re-applied to 88 participants in a 7-day interval. Cronbach's alpha of the WHQ-R was 0.984 and that of the WFQ was 0.905. The test-retest intra-class correlation coefficients (ICC) of the WHQ-R varied from 0.741 to 0.933 and those of the WFQ-R from 0.649 to 0.814. There were moderate to strong correlations between the WHQ-R and the Handedness Questionnaire (r = -853, p < 0.001) and between the WFQ-R and the Footedness Preference Test (r = -0.687, p < 0.001). Confirmatory factor analysis revealed a two-factor structure of the WHQ-R and the WFQ-R. The results of this study demonstrated that Turkish versions of the WHQ-R and the WFQ-R are reliable and valid inventories for assessing handedness and footedness in this population.

The contributions of handedness and working memory to episodic memory

Past studies have independently shown associations of working memory and degree of handedness with episodic memory retrieval. The current study takes a step ahead by examining whether handedness and working memory independently predict episodic memory. In agreement with past studies, there was an inconsistent-handed advantage for episodic memory; however, this advantage was absent for working memory tasks. Furthermore, regression analyses showed handedness, and complex working memory predicted episodic memory performance at different times. Results are discussed in light of theories of episodic memory and hemispheric interaction.

Dissociative experiences in patients with epilepsy

A few studies have explored dissociative experiences in epilepsy patients. We investigated dissociative experiences in patients with epilepsy using the dissociative experiences scale (DES). Ninety-eight patients with epilepsy and sixty healthy controls were enrolled in this study. A sociodemographic questionnaire and the Dissociative Experiences Scale (DES), Beck Depression Inventory (BDI) and Beck Anxiety Inventory (BAI) were administered to the participants. The DES scores were significantly higher for the patients with epilepsy than the healthy individuals. The number of individuals with pathological dissociation (DES ≥ 30) was higher in the epilepsy group (n = 28) than in the control group (n = 8). Also, higher levels of dissociation were significantly associated with frequency of seizures, but were not associated with duration of epilepsy and age at onset of the disorder. These findings demonstrate that patients with epilepsy are more prone to dissociation than controls. The high rate of dissociative experiences among patients with epilepsy suggest that some epilepsy-related factors are present.

The Relationships Between Dissociation, Attention, and Memory Dysfunction

INTRODUCTION

Dissociation is a disruption in the integrated functions of consciousness, memory, identity, and perception. Dissociative symptoms include derealization/depersonalization, absorption, and amnesia. These experiences can cause a loss of control over mental processes, including memory and attention. In literature, there is a paucity of research concerning the relationships between dissociation and memory performance. In this study, our aim was to investigate the relationships between dissociative experiences, attention, and memory performance in a non-clinical community sample.

METHODS

In this study, we examined the relationship between dissociation and cognitive dysfunction among 60 healthy volunteers. We administered the Wechsler Memory Scale-Revised, Auditory Verbal Learning Test, Stroop Color Word Interference Test, and Dissociative Experience Scale. Here we examined the relationships between the subtypes of dissociation and memory performance as assessed by neuropsychological tests.

RESULTS

We found that verbal memory was negatively associated with dissociative experiences. Pathological dissociation, particularly amnesia and depersonalization/derealization, was reversely linked to general memory performance and long-term memory. Moreover, low dissociators reported higher scores on verbal memory, general memory performance, and long-term memory but lower scores on recognition than high dissociators.

CONCLUSION

The results of our study suggested that there are significant linkages between dissociative experiences and memory performance.

Score reliability and construct validity of the Flinn Performance Screening Tool for adults with symptoms of carpal tunnel syndrome

OBJECTIVE

We investigated the psychometric properties of the Flinn Performance Screening Tool (FPST) for people referred with symptoms of carpal tunnel syndrome (CTS).

METHOD

An occupational therapist collected data from 46 participants who completed the Functional Status Scale (FSS) and FPST after the participants' nerve conduction velocity study to test convergent and contrasted-group validity.

RESULTS

Seventy-four percent of the participants had abnormal nerve conduction studies. Cronbach's α coefficients for subscale and total scores of the FPST ranged from .96 to .98. Intrarater reliability for six shared items of the FSS and the FPST was supported by high agreement (71%) and a fair κ statistic (.36). Strong to moderate positive relationships were found between the FSS and FPST scores. Functional status differed significantly among severe, mild, and negative CTS severity groups.

CONCLUSION

The FPST shows adequate psychometric properties as a client-centered screening tool for occupational performance of people referred for symptoms of CTS.

Dissociative mental states are canonically associated with decreased temporal theta activity on spectral analysis of EEG

Quantitative electroencephalographic (QEEG) changes relating to dissociative experiences have only rarely been demonstrated, and dissociative states were not quantified in those studies. The aim of this study was to explore concurrent associations between quantified dissociative states and QEEG spectral parameters, in particular theta activity, in psychiatric patients. Fifty psychiatric patients completed the State Scale of Dissociation (SSD) immediately after a 15-min EEG recording. The EEG was assessed by conventional clinical visual analysis as well as by quantitative (QEEG) spectral analysis. Canonical analysis was performed between the set of SSD subscale scores and the following QEEG parameters: alpha-theta magnitude ratios, and relative as well as absolute theta magnitude obtained from right and left mid- to posterior-temporal and parieto-occipital derivations. The SSD transferred well to the present data in terms of reliability and internal criterion-related validity. The SSD and Dissociative Experiences Scale (DES) correlated significantly (r = .73, p < .001). Conventional EEG analysis identified 29 EEGs (58%) as abnormal. The main abnormality in 23 EEGs was slowing, maximal temporally in half of these cases. Canonical analyses confirmed a statistically significant relationship between the dissociation variables (especially conversion and depersonalization symptoms) and the QEEG variables (especially relative theta magnitude in the temporal regions; R = .72, p = .03, for SSD-QEEG; and R = .66, p = .04, for DES-QEEG). Quantified dissociative mental states are positively canonically associated with decreased temporal theta activity and increased alpha-theta ratios on QEEG in psychiatric patients with a high tendency to dissociate. The potential implications of the dissociation-theta-alpha relationship for understanding normal attentional processes need to be studied further.