Does repetitive transcranial magnetic stimulation improve cognitive function in age-related neurodegenerative diseases? A systematic review and meta-analysis.

OBJECTIVE: High-frequency, repetitive transcranial magnetic stimulation (rTMS) targeted over the dorsolateral prefrontal cortex (DLPFC) is widely used in research to promote neuroplasticity and cognitive enhancement. RTMS is a promising intervention to tackle cognitive decline in people with age-related neurodegenerative diseases. However, there is currently no systematic evidence examining the effects of DLPFC-targeted, high-frequency rTMS on cognitive function in this population. The aim of this systematic review was to evaluate the efficacy and moderators of this treatment intervention. METHODS: A comprehensive literature search of five electronic databases was performed to identify articles published before October, 2022. Following PRISMA guidelines, the identified articles were screened, data was extracted, and the methodological quality was assessed using the Cochrane tool, Risk of Bias 2. Meta-analyses were performed using R Studio (v.4.1.2). RESULTS: Sixteen studies involving 474 participants met the inclusion criteria, of which 8 studies measured global cognitive function. The results from the random-effects meta-analysis showed rTMS significantly improved global cognitive function relative to control groups shown by a large, significant effect size (g = 1.39, 95% CI, 0.34-2.43; p = 0.017). No significant effects were found between subgroups or for individual cognitive domains. CONCLUSIONS: High-frequency rTMS, targeted over the DLPFC, appears to improve global cognitive function in people with age-related neurodegenerative diseases. However, these results should be interpreted with caution due to the small number of studies included, and high between-study heterogeneity.

Are syntactic representations similar in both reading and listening? Evidence from priming in first and second languages.

It is unclear to what extent natural differences between reading and listening result in differences in the syntactic representations formed in each modality. The present study investigated the occurrence of syntactic priming bidirectionally from reading to listening, and vice versa to examine whether reading and listening share the same syntactic representations in both first language (L1) and second language (L2). Participants performed a lexical decision task in which the experimental words were embedded in sentences with either an ambiguous or a familiar structure. These structures were alternated to produce a priming effect. The modality was manipulated whereby participants (a) first read part of the sentence list and then listened to the rest of the list (reading-listening group), or (b) listened and then read (listening-reading group). In addition, the study involved two within-modality lists in which participants either read or listened to the whole list. The L1 group showed within-modal priming in both listening and reading as well as a cross-modal priming effect. Although L2 speakers showed priming in reading, the effect was absent in listening and weak in the listening-reading condition. The absence of priming in L2 listening was attributed to difficulties in L2 listening rather than to an inability to produce abstract priming.

Identifying the needs of people with long COVID: a qualitative study in the UK.

OBJECTIVES: To identify the needs of people with long COVID (LC) in the UK. DESIGN: Qualitative study using the Framework Analysis to analyse focus group discussions. PARTICIPANTS: 25 adults with LC aged 19-76 years including 17 men and 8 women. Average disease duration was 80.1 weeks. SETTING: Eight focus groups were conducted in April 2023 online and in-person at the University of Leeds (UoL), UK. Recruitment routes included advertisement via Leeds Community Healthcare services, the English National Opera Breathe Programme and within the UoL. RESULTS: Three key themes/needs were identified. (Theme 1) Support systems including community groups, disability benefits, clinical services and employment support should be accessible and tailored to the needs of people with LC. (Theme 2) Research should investigate the physiology of symptoms, new clinical tests and treatment interventions to improve clinical understanding of the condition and symptom management. (Theme 3) Societal awareness should be promoted via local and national initiatives to educate the public about the condition and reduce stigma. CONCLUSIONS: Participants experienced varied and individual challenges to daily life due to LC. There is a need for government acknowledgement of LC as a disability to ensure people with LC have access to disability support and legal protection. Policy development should be patient-driven and acknowledge the individual needs of people with LC in order to improve their quality of life.

The neural correlates of inhibiting pursuit to smoothly moving targets.

A previous study has shown that actively pursuing a moving target provides a predictive motor advantage when compared with passive observation of the moving target while keeping the eyes still [Burke, M. R., & Barnes, G. R. Anticipatory eye movements evoked after active following versus passive observation of a predictable motion stimulus. Brain Research, 15, 74-81, 2008b]. By using a novel paradigm based on combining a smooth pursuit stimulus with a go/no-go task, we have been able to reveal significant differences in brain activity for the inhibition of pursuit during the presentation of a smoothly moving target. Areas that show specific inhibitory and retinocentric velocity storage activity for the passive (no-go) condition include the dorsolateral pFC, the caudate, and the posterior cingulate. The FEFs, the supramarginal gyrus, the medial occipital gyrus, and the superior parietal lobe were found to be more involved in both the acquisition and response generation during no-go trials when compared with go trials. The go trials revealed higher activity than the no-go during the acquisition phase in the uncus and posterior cingulate. Furthermore, higher motor-related activity in the go task was found in the cerebellum. In summary, the areas involved in inhibiting smooth pursuit are consistent with the findings from the saccade literature, providing further evidence in support of overlapping cortical control networks.

Splenium tracts of the corpus callosum degrade in old age.

It is well established that the posterior region of the corpus callosum, known as the splenium, is relatively preserved during the course of normal ageing. However, the effect of age on its distinct interhemispheric tract bundles that project to bilateral occipital, parietal and temporal areas of the cortex, is largely unknown. In the present study, diffusion tensor imaging was used to directly examine the integrity of these distinct segregations and their diffusion metrics were compared between groups of young adults (n = 20, mean age = 30.75) and older adults (n = 19, mean age = 80.21). Results revealed that while occipital tracts were preserved in older adults, parietal and temporal segments were particularly impaired. These findings are the first to indicate the existence of selective alterations in the posterior region of the corpus callosum in older age.

Resting-state EEG power and connectivity are associated with alpha peak frequency slowing in healthy aging.

The individual alpha peak frequency (IAPF) of the human electroencephalography (EEG) typically experiences slowing with increasing age. Despite this hallmark change, studies that investigate modulations of conventional EEG alpha power and connectivity by aging and age-related neuropathology neglect to account for intergroup differences in IAPF. To investigate the relationship of age-related IAPF slowing with EEG power and connectivity, we recorded eyes-closed resting-state EEG in 37 young adults and 32 older adults. We replicated the finding of a slowed IAPF in older adults. IAPF values were significantly correlated with the frequency of maximum global connectivity and the means of their distributions did not differ, suggesting that connectivity was highest at the IAPF. Older adults expressed reduced global EEG power and connectivity at the conventional upper alpha band (10-12 Hz) compared with young adults. By contrast, groups had equivalent power and connectivity at the IAPF. The results suggest that conventional spectral boundaries may be biased against older adults or any group with a slowed IAPF. We conclude that investigations of alpha activity in aging and age-related neuropathology should be adapted to the IAPF of the individual and that previous findings should be interpreted with caution. EEG in the dominant alpha range may be unsuitable for examining cortico-cortical connectivity due to its subcortical origins.

Visual and visuomotor interhemispheric transfer time in older adults.

Older adults typically experience reductions in the structural integrity of the anterior channels of the corpus callosum. Despite preserved structural integrity in central and posterior channels, many studies have reported that interhemispheric transfer, a function attributed to these regions, is detrimentally affected by aging. In this study, we use a constrained event-related potential analysis in the theta and alpha frequency bands to determine whether interhemispheric transfer is affected in older adults. The crossed-uncrossed difference and lateralized visual evoked potentials were used to assess interhemispheric transfer in young (18-27) and older adults (63-80). We observed no differences in the crossed-uncrossed difference measure between young and older groups. Older adults appeared to have elongated transfer in the theta band potentials, but this effect was driven by shortened contralateral peak latencies, rather than delayed ipsilateral latencies. In the alpha band, there was a trend toward quicker transfer in older adults. We conclude that older adults do not experience elongated interhemispheric transfer in the visuomotor or visual domains and that these functions are likely attributed to posterior sections of the corpus callosum, which are unaffected by aging.

Age-Related Deficits in Visuospatial Memory Are due to Changes in Preparatory Set and Eye-Hand Coordination.

OBJECTIVES: Healthy aging is associated with a decline in visuospatial working memory. The nature of the changes leading to this decline in response of the eye and/or hand is still under debate. This study aims to establish whether impairments observed in performance on cognitive tasks are due to actual cognitive effects or are caused by motor-related eye-hand coordination. METHODS: We implemented a computerized version of the Corsi span task. The eye and touch responses of healthy young and older adults were recorded to a series of remembered targets on a screen. RESULTS: Results revealed differences in fixation strategies between the young and the old with increasing cognitive demand, which resulted in higher error rates in the older group. We observed increasing reaction times and durations between fixations and touches to targets, with increasing memory load and delays in both the eye and the hand in the older adults. DISCUSSION: Our results show that older adults have difficulty maintaining a "preparatory set" for durations longer than 5 s and with increases in memory load. Attentional differences cannot account for our results, and differences in age groups appear to be principally memory related. Older adults reveal poorer eye-hand coordination, which is further confounded by increasing delay and complexity.

A Systematic Research Review Assessing the Effectiveness of Pursuit Interventions in Spatial Neglect Following Stroke.

Rehabilitation after stroke is imperative for patients with spatial neglect as it can help improve behavioural, social and cognitive outcomes in these patients, and therefore reduce the financial burden on public health services. The main aim of this review is to investigate the effectiveness of active pursuit eye movements for rehabilitation interventions in patients with spatial neglect following stroke. Potential papers for inclusion were gathered by searching key terms in four main databases (AMED, Global Health, PubMed/Medline and PsychInfo) in addition to screening relevant reference lists. Two reviewers independently selected papers for inclusion based on agreed inclusion criteria (n = 9 with 147 participants). Risk of bias was assessed using the QUADAS-2 tool. All papers reported a statistically significant result in patients who received an intervention which used pursuit eye movements, and this was reported both as a short-term (immediate) effect and as a sustained effect up to 8 weeks after treatment. These effects were also reported in comparison with interventions using saccadic eye movements. One study also reported increased neural activity in a number of brain regions following pursuit-based intervention. Overall, there is good evidence in support of pursuit intervention used in the rehabilitation of stroke and spatial neglect over and above traditional interventions based on saccadic eye movements. Future research should aim to increase sample sizes, provide information on statistical power, record accurate eye movement responses and use randomised designs to reduce selection bias.