Comment on Muth et al. Assessing Critical Flicker Fusion Frequency: Which Confounders? A Narrative Review. Medicina 2023, 59, 800.

We first want to thank the authors of the excellent review for their contributions to summarizing the confounders associated with critical flicker fusion frequency (CFFF) [...].

Physical activity and the brain myelin content in humans.

New imaging sequences and biophysical models allow adopting magnetic resonance imaging (MRI) for in vivo myelin mapping in humans. Understanding myelination and remyelination processes in the brain is fundamental from the perspective of proper design of physical exercise and rehabilitation schemes that aim to slow down demyelination in the aging population and to induce remyelination in patients with neurodegenerative diseases. Therefore, in this review we strive to provide a state-of-the art summary of the existing MRI studies in humans focused on the effects of physical activity on myelination/remyelination. We present and discuss four cross-sectional and four longitudinal studies and one case report. Physical activity and an active lifestyle have a beneficial effect on the myelin content in humans. Myelin expansion can be induced in humans throughout the entire lifespan by intensive aerobic exercise. Additional research is needed to determine (1) what exercise intensity (and cognitive novelty, which is embedded in the exercise scheme) is the most beneficial for patients with neurodegenerative diseases, (2) the relationship between cardiorespiratory fitness and myelination, and (3) how exercise-induced myelination affect cognitive abilities.

Cognitive Functions in Scuba, Technical and Saturation Diving.

Scuba diving as a recreational activity is becoming increasingly popular. However, the safety of this activity, especially in the out-of-comfort zone, has been discussed worldwide. The latest publications bring conclusions regarding negative effects on cognitive functions. We compare the acute and chronic effects of diving on cognitive functioning depending on the type of dive performed, including recreational, technical and saturation diving. However, the results of research show that acute and chronic effects on cognitive functions can be negative. While acute effects are reversible after the ascent, chronic effects include white matter lesions in magnetic resonance imaging scans. We believe that more investigations should be performed to determine the chronic effects that could be observed after a few months of observations in a group of regular, intense divers. In addition, publications referring to technical divers are very limited, which is disquieting, as this particular group of divers seems to be neglected in research concerning the effects of diving on cognitive functions.

Neuropsychological and Neurophysiological Mechanisms behind Flickering Light Stimulus Processing.

The aim of this review is to summarise current knowledge about flickering light and the underlying processes that occur during its processing in the brain. Despite the growing interest in the topic of flickering light, its clinical applications are still not well understood. Studies using EEG indicate an appearing synchronisation of brain wave frequencies with the frequency of flickering light, and hopefully, it could be used in memory therapy, among other applications. Some researchers have focused on using the flicker test as an indicator of arousal, which may be useful in clinical studies if the background for such a relationship is described. Since flicker testing has a risk of inducing epileptic seizures, however, every effort must be made to avoid high-risk combinations, which include, for example, red-blue light flashing at 15 Hz. Future research should focus on the usage of neuroimaging methods to describe the specific neuropsychological and neurophysiological processes occurring in the brain during the processing of flickering light so that its clinical utility can be preliminarily determined and randomised clinical trials can be initiated to test existing reports.

Tuberous sclerosis complex-associated neuropsychiatric disorders. / Zaburzenia neuropsychiatryczne zwiazane ze stwardnieniem guzowatym.

The aim of the study was to provide a state-of-the-art review with regard to neuropsychiatric disorders associated with tuberous sclerosis complex (TSC). TSC is a rare genetic disease classified as a phacomatosis. Due to the wide spectrum of clinical symptoms of the disease, many cases remain undiagnosed. The vast majority of people with a mutation in the TSC1 or TSC2 genes develop some of the neuropsychiatric symptoms during their lifetime. Diagnostic criteria, neuroanatomical pathology and pathophysiology of psychiatric, neuropsychological, developmental and psychosocial symptoms present in TSC are described. The specificity of epilepsy in TSC and its role in neuropsychiatric and neuropsychological development are presented. All levels (intellectual, developmental, behavioral, psychiatric, school, neuropsychological and psychosocial) of tuberous sclerosis complex-associated neuropsychiatric disorders (TAND) are discussed in detail. The TAND Checklist - a tool for assessing all potentially disturbed aspects of functioning - was presented. The importance of proper diagnosis of neuropsychiatric disorders and multidisciplinary patient care was emphasized.

Tuberous Sclerosis Complex Patients' Needs and Difficulties-Results of TAND Questionnaire Analysis in Polish Adult Population.

INTRODUCTION: Tuberous Sclerosis Complex (TSC) is a rare genetic disease. Around 90% of individuals with TSC present some neuropsychiatric manifestations (TSC-associated neuropsychiatric disorders, TAND). To date, none of the studies have focused on the TAND profile of the adult population. Thus, the aim of the study was to describe their potential specific needs and difficulties, including differences in cohorts with or without epilepsy and/or intellectual disability. METHOD: The Polish version of the TAND Checklist was used for assessment of individuals with TSC. Participants had to meet the criteria for diagnosis of TSC. One hundred adult participants (forty-eight males/ fifty-two females; mean age 32.33 ± 11.29) were enrolled in the study. Epilepsy was present in 71% of patients; intellectual disability occurred in a total of 37%. RESULTS: Only 11% of individuals received complete TAND features examination in the past. Moreover, 91.5 of the subjects had four and more TAND symptoms. Intellectually disabled patients and those with epilepsy had more neuropsychiatric problems than epilepsy-free subjects. CONCLUSIONS: Findings reveal that TANDs are common in adults with TSC and are underdiagnosed. Most individuals present several behavioural and cognitive problems. Among psychiatric disorders, the most common are ASD, depression, and anxiety disorder. TAND screening should be widely disseminated and applied in clinical practice for early identification, prevention, and rehabilitation of their difficulties. TAND is one of the most significant issues affecting the quality of life of TSC patients and their carers.

Reply to Vrijdag et al. Comment on "Mankowska et al. Critical Flicker Fusion Frequency: A Narrative Review. Medicina 2021, 57, 1096".

Thank you very much for your interest and comments [...].

A Systematic Review of the Impact of Physical Exercise-Induced Increased Resting Cerebral Blood Flow on Cognitive Functions.

Brain perfusion declines with aging. Physical exercise represents a low-cost accessible form of intervention to increase cerebral blood flow; however, it remains unclear if exercise-induced amelioration of brain perfusion has any impact on cognition. We aimed to provide a state-of-the art review on this subject. A comprehensive search of the PubMed (MEDLINE) database was performed. On the basis of the inclusion and exclusion criteria, 14 studies were included in the analysis. Eleven of the studies conducted well-controlled exercise programs that lasted 12-19 weeks for 10-40 participants and two studies were conducted in much larger groups of subjects for more than 5 years, but the exercise loads were indirectly measured, and three of them were focused on acute exercise. Literature review does not show a direct link between exercise-induced augmentation of brain perfusion and better cognitive functioning. However, in none of the reviewed studies was such an association the primary study endpoint. Carefully designed clinical studies with focus on cognitive and perfusion variables are needed to provide a response to the question whether exercise-induced cerebral perfusion augmentation is of clinical importance.

Arginine Vasopressin, Synaptic Plasticity, and Brain Networks.

The arginine vasopressin (AVP), a neurohypophysial hormone, is synthesized within specific sites of the central nervous system and axonally transported to multiple areas, acting as a neurotransmitter/ neuromodulator. In this context, AVP acts primarily through vasopressin receptors A and B and is involved in regulating complex social and cognition behaviors and basic autonomic function. Many earlier studies have shown that AVP as a neuromodulator affects synaptic plasticity. This review updates our current understanding of the underlying molecular mechanisms by which AVP affects synaptic plasticity. Moreover, we discuss AVP modulatory effects on event-related potentials and blood oxygen level-dependent responses in specific brain structures, and AVP effects on the network level oscillatory activity. We aimed at providing an overview of the AVP effects on the brain from the synaptic to the network level.

Impact of Hyperbaric Oxygen Therapy on Cognitive Functions: a Systematic Review.

Hyperbaric oxygen therapy (HBOT) is a modality of treatment in which patients inhale 100% oxygen inside a hyperbaric chamber pressurised to greater than 1 atmosphere. The aim of this review is to discuss neuropsychological findings in various neurological disorders treated with HBOT and to open new perspectives for therapeutic improvement. A literature search was conducted in the MEDLINE (via PubMed) database from the inception up 10 May 2020. Eligibility criteria included original articles published in English. Case studies were excluded. Full-text articles were obtained from the selected studies and were reviewed on the following inclusion criteria (1) performed cognitive processes assessment (2) performed HBOT with described protocol. Two neuropsychologists independently reviewed titles, abstracts, full texts and extracted data. The initial search retrieved 1024 articles, and a total of 42 studies were finally included after applying inclusion and exclusion criteria. The search yielded controversial results with regard to the efficiency of HBOT in various neurological conditions with cognitive disturbance outcome. To the best of our knowledge this is the first state-of-the art, systematic review in the field. More objective and precise neuropsychological assessment methods are needed to exact evaluation of the efficacy of HBOT for neuropsychological deficits. Future studies should widen the assessment of HBOT effects on different cognitive domains because most of the existing studies have focussed on a single process. Finally, there is a need for further longitudinal studies.

Critical Flicker Fusion Frequency: A Narrative Review.

This review presents the current knowledge of the usage of critical flicker fusion frequency (CFF) in human and animal model studies. CFF has a wide application in different fields, especially as an indicator of cortical arousal and visual processing. In medicine, CFF may be helpful for diagnostic purposes, for example in epilepsy or minimal hepatic encephalopathy. Given the environmental studies and a limited number of other methods, it is applicable in diving and hyperbaric medicine. Current research also shows the relationship between CFF and other electrophysiological methods, such as electroencephalography. The human eye can detect flicker at 50-90 Hz but reports are showing the possibility to distinguish between steady and modulated light up to 500 Hz. Future research with the use of CFF is needed to better understand its utility and application.