Electrophysiological modulation of sensory and attentional processes during mind wandering in attention-deficit/hyperactivity disorder

Acousto-optic stimuli to promote coherent 40-Hz frequency entrainment effect

BACKGROUND

 Research has shown that a fundamental frequency of 40 Hz in continuous neural oscillation is indicative of normal brain activity; in Alzheimer disease (AD) patients, these oscillations either disappear or are significantly interrupted. Research has also indicated that the degenerative impacts of AD in mice were mitigated by the synchronization of 40-Hz acousto-optic stimulation (AOS).

OBJECTIVE

 To examine the impact of employing a 40-Hz AOS intervention on the induction of a substantial 40-Hz frequency entrainment and improvement in working memory performance among a sample of young individuals in good health. We conduct an analysis of event-related potentials (ERPs) derived from electroencephalogram (EEG) data following the presentation of AOS.

METHODS

 We recruited 20 healthy volunteers (median age: 25 years; 8 female subjects). Following the administration of various stimuli, including no stimuli, 40-Hz AOS, pink noise, and 40Hz acoustic stimuli (AS), the participants were required to complete a working memory task. A total of 62 electrodes were used to record EEG data, which was subsequently analyzed to investigate the impact of AOS on the activity of working memory. We also aimed to determine if AOS lead to a more pronounced 40-Hz frequency entrainment.

RESULTS

 Following the administration of AOS, a notable enhancement in the 40-Hz power of pertinent cerebral areas was observed, accompanied by a substantial improvement in the performance of the subjects on working memory tests subsequent to the stimulation.

CONCLUSION

 The findings unequivocally establish the efficacy of using AOS to enhance the 40-Hz power and working memory.

Spanish and cross-cultural validation of the mind excessively wandering scale

Introduction

Over the last decade, excessive spontaneous mind wandering (MW) has been consistently associated with emotional disorders. The main aims of the present study were (1) to re-examine the factor structure of the Mind Excessively Wandering Scale (MEWS); (2) to validate the Spanish version of the MEWS; and (3) to conduct a cross-cultural validation of the MEWS in Spanish and UK samples.

Methods

A forward/backward translation to Spanish was conducted. Data of 391 Spanish and 713 British non-clinical individuals were analysed.

Results

A revised 10-item version of the MEWS (MEWS-v2.0) demonstrated to be a valid instrument to assess MW. A 2-correlated factor structure properly captured the MEWS-v2.0 variance, accounting for two specific but interrelated dimensions (Uncontrolled thoughts and Mental Overactivity).

Discussion

The Spanish MEWS-v2.0 showed adequate internal consistency and construct validity, as well as appropriate convergent/divergent validity. Cross-cultural analyses showed that MEWS-v2.0 captured the same construct in both UK and Spanish samples. In conclusion, both Spanish and English MEWS-v2.0 demonstrated to be reliable measures to capture spontaneous MW phenomenon in non-clinical adult populations.

More than off-task: Increased freely-moving thought in ADHD

Off-task thought has been found to occur at high rates and is related to impairment in ADHD. However, off-task thought is heterogenous and it remains unclear which specific dimensions of off-task thought are more prevalent in this disorder. It is therefore important to dissociate different aspects of off-task thought in order to better understand the mechanisms underlying impairment. The current study focused on the dimension of constrained (focused) to freely moving off-task thought. Self-report and neurophysiological measures during a computerized attention tasks provided convergent evidence that individuals with ADHD not only have more off-task thought than those without, but also engaged in a greater proportion of freely moving off-task thought than non-ADHD controls. Overall, this work demonstrated differences in both the quantity and type of off-task thought in adults with ADHD. It provides novel insight into both the phenomenology of off-task thought, as well as potential mechanisms underlying impairment in ADHD.