Effects of Multi-Sensory Stimulation on Apathy Symptoms in Elderly Patients with Alzheimer's Disease.

Background: We aimed to explore the effect of multi-sensory stimulation on apathy symptoms in elderly patients with Alzheimer's disease (AD). Methods: Eighty elderly patients with AD admitted to the Third Affiliated Hospital of Qiqihar Medical University, China from January 2022 to February 2023 were selected as the research objects by convenient sampling method. According to the random number table, they were divided into intervention group and control group, with 40 cases in each group. The control group was given routine nursing, while the intervention group was given multi-sensory stimulation based on this nursing. Apathy evaluation scale (AES), Behavioral pathology in Alzheimer's disease rating scale (BEHAVE-AD) and Quality of Life Scale for dementia patients (QoL-AD) were used to compare the results. Results: Compared with the control group, the scores of AES and BEHAVE-AD in intervention group were lower (t was -7.312 and 11.88 respectively, P < 0.05), and the scores of QoL-AD in intervention group were significantly higher than those in control group were (t was -15.311, P < 0.01). Conclusion: Multi-sensory stimulation can relieve apathy symptoms, mental and behavioral symptoms and improve the quality of life of elderly patients with AD, which is worth popularizing in clinical practice.

Intersection between person-centred practice and Montessori for dementia and ageing in residential aged care.

BACKGROUND: Internationally, person-centred care (PCC) is embedded in the language of regulations and mandated to be practised in residential aged care (RAC). Despite this, PCC has not been fully adopted in RAC in Australia and internationally, and concerns about the quality of care persist. Over the past 2 decades, Montessori for dementia and ageing has been introduced in RAC to support and inform a cultural change towards PCC. This study aimed to examine the intersection between the goals and approaches of Montessori and PCC in RAC. METHODS: This qualitative descriptive study reports on a secondary analysis of qualitative data from focus groups (FGs) and interviews with residents, family-members, staff, and volunteers from eight RAC homes in Victoria, Australia. Sixteen FGs and 36 interviews were conducted. A qualitative deductive approach using researcher-developed Montessori for dementia and ageing framework for data analysis was applied. RESULTS: Findings provide support for the intersection between PCC and Montessori with participants' descriptions of PCC aligning with many of the goals and approaches of Montessori. Participants most commonly described Montessori approaches of engagement in daily tasks with purposeful roles and promoting cognitive abilities through multi-sensory stimulation. Least frequently-described approaches included focusing on residents' strengths/abilities, maintaining function, using familiar objects, and guided repetition. CONCLUSIONS: Findings have important implications for practice to use Montessori as a vehicle that supports and upskills the workforce to deliver care that is person-centred. Future research must examine the resources required to support the implementation and sustainability of Montessori as a vehicle for PCC.

The Use of TheraBracelet Upper Extremity Vibrotactile Stimulation in a Child with Cerebral Palsy-A Case Report.

Background: TheraBracelet is peripheral vibrotactile stimulation applied to the affected upper extremity via a wristwatch-like wearable device during daily activities and therapy to improve upper limb function. The objective of this study was to examine feasibility of using TheraBracelet for a child with hemiplegic cerebral palsy. Methods: A nine-year-old male with cerebral palsy was provided with TheraBracelet to use during daily activities in the home and community settings for 1.5 years while receiving standard care physical/occupational therapy. Results: The child used TheraBracelet independently and consistently except during summer vacations and elbow-to-wrist orthotic use from growth spurt-related contracture. The use of TheraBracelet did not impede or prevent participation in daily activities. No study-related adverse events were reported by the therapist, child, or parent. Conclusion: Future research is warranted to investigate TheraBracelet as a propitious therapeutic device with focus on potential impact of use to improve the affected upper limb function in daily activities in children with hemiplegic cerebral palsy.

Blue Space: Extracting the Sensory Characteristics of Waterscapes as a Potential Tool for Anxiety Mitigation.

Objective: The purpose of this study is to investigate if there is a physiological stress response to the visual and auditory characteristics of waterscapes. Background: Biophilic research suggests that the presence of water can reduce stress, reduce blood pressure, and increase circulation. However, water has largely been omitted from healthcare design due to concerns of cost, maintenance, waterborne pathogens, and contamination. Existing research has not yet provided a design methodology to incorporate the healing effects of water without the potential diseases, contamination, and maintenance issues associated with physical water. Given the current technological capabilities, the isolation of the auditory and visual sensory stimuli has potential to re-introduce the healing benefits of water into healthcare design. Methods: Participants were either exposed to a slow-moving or fast-moving waterscape for 20 minutes. Pre- and post-anxiety were measured using the State Trait Anxiety Scale in an online Qualtrics survey (118 participants) and through a salivary cortisol biomarker (in which 26 participants also partook). Results: The overall results demonstrate that the utilization of digital blue space was effective in reducing stress. There was no significant difference between the lake or waterfall environment in both salivary cortisol and state-trait anxiety measures. However, it is suggested that the slow and fast-moving waterscapes may be beneficial in different settings. Conclusion: Design recommendations are made regarding potential biophilic design in healthcare facilities. The utilization of sensory waterscapes can also provide a cost affordable, non-pharmacological, alternative for anxiety mitigation for patients and staff undergoing high-stress situations.

[Virtual reality-brain computer interface hand function enhancement rehabilitation system incorporating multi-sensory stimulation].

Stroke is an acute cerebrovascular disease in which sudden interruption of blood supply to the brain or rupture of cerebral blood vessels cause damage to brain cells and consequently impair the patient's motor and cognitive abilities. A novel rehabilitation training model integrating brain-computer interface (BCI) and virtual reality (VR) not only promotes the functional activation of brain networks, but also provides immersive and interesting contextual feedback for patients. In this paper, we designed a hand rehabilitation training system integrating multi-sensory stimulation feedback, BCI and VR, which guides patients' motor imaginations through the tasks of the virtual scene, acquires patients' motor intentions, and then carries out human-computer interactions under the virtual scene. At the same time, haptic feedback is incorporated to further increase the patients' proprioceptive sensations, so as to realize the hand function rehabilitation training based on the multi-sensory stimulation feedback of vision, hearing, and haptic senses. In this study, we compared and analyzed the differences in power spectral density of different frequency bands within the EEG signal data before and after the incorporation of haptic feedback, and found that the motor brain area was significantly activated after the incorporation of haptic feedback, and the power spectral density of the motor brain area was significantly increased in the high gamma frequency band. The results of this study indicate that the rehabilitation training of patients with the VR-BCI hand function enhancement rehabilitation system incorporating multi-sensory stimulation can accelerate the two-way facilitation of sensory and motor conduction pathways, thus accelerating the rehabilitation process.

Provoking lucid dreams at home with sensory cues paired with pre-sleep cognitive training.

The ability to realize that you're dreaming - lucid dreaming - has value for personal goals and for consciousness research. One route to lucid dreaming is to first undergo pre-sleep training with sensory cues and then receive those cues during REM sleep. This method, Targeted Lucidity Reactivation (TLR), does not demand extensive personal effort but generally requires concurrent polysomnography to guide cue delivery. Here we translated TLR from a laboratory procedure to a smartphone-based procedure without polysomnography. In a first experiment, participants reported increased lucid dreaming with TLR compared to during the prior week. In a second experiment, we showed increased lucidity with TLR compared to blinded control procedures on alternate nights. Cues during sleep were effective when they were the same sounds from pre-sleep training. Increased lucid dreaming can be ascribed to a strong link formed during training between the sounds and a mindset of carefully analyzing one's current experience.

Exploring the impact of bubble type on sensory stimulation in drinks.

This study explores the impact of various types of carbonation on sensory stimulation in the mouth, salivary secretion and the neurotransmitter substance P (SP), as well as body responses such as heart rate (HR) and Galvanic Skin Response (GSR). Three types of carbonation (one made using a soda machine, another carbonated with a gasifier, and the last commercial sparkling water) were used to produce different bubbles resulting in distinct sensory characteristics assessed by a trained panel. The impact of carbonation was measured by recording changes in salivary flow rate, SP levels, salivary secretory immunoglobulin A (SIgA), HR, and GSR in fifteen healthy participants. The results showed that the bubble type only affected the sensory perception of carbonation. Regardless of bubble type, carbonation increased salivary flow rate and SP values, SigA and HR. These characteristics are being sought to improve treatments for dysphagia or dry mouth. Therefore, these findings highlight the potential therapeutic application of carbonation in these situations.

Effects of Auditory and Visual White Noise on Oculomotor Inhibition in Children With Attention-Deficit/Hyperactivity Disorder: Protocol for a Crossover Study.

BACKGROUND: In attention-deficit/hyperactivity disorder (ADHD), poor inhibitory control is one of the main characteristics, with oculomotor inhibition impairments being considered a potential biomarker of the disorder. While auditory white noise has demonstrated the ability to enhance working memory in this group, visual white noise is still unexplored and so are the effects of both types of white noise stimulation on oculomotor inhibition. OBJECTIVE: This crossover study aims to explore the impact of auditory and visual white noise on oculomotor inhibition in children with ADHD and typically developing (TD) children. The study will investigate the impact of different noise levels (25% and 50% visual, 78 dB auditory), and performance will be evaluated both with and without noise stimulation. We hypothesize that exposure to white noise will improve performance in children with ADHD and impair the performance for TD children. METHODS: Memory-guided saccades and prolonged fixations, known for their sensitivity in detecting oculomotor disinhibition in ADHD, will be used to assess performance. Children diagnosed with ADHD, withdrawing from medication for 24 hours, and TD children without psychiatric disorders were recruited for the study. RESULTS: Data collection was initiated in October 2023 and ended in February 2024. A total of 97 participants were enrolled, and the first results are expected between September and November 2024. CONCLUSIONS: This study will examine whether cross-modal sensory stimulation can enhance executive function, specifically eye movement control, in children with ADHD. In addition, the study will explore potential differences between auditory and visual noise effects in both groups. Our goal is to identify implications for understanding how noise can be used to improve cognitive performance. TRIAL REGISTRATION: ClinicalTrials.gov NCT06057441; https://clinicaltrials.gov/study/NCT06057441. INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID): DERR1-10.2196/56388.

Inhibition of muscle sympathetic nerve activity in premenopausal women: responses to sudden sensory stimuli predict responses to mental stress.

Muscle sympathetic nerve responses to sudden sensory stimuli have been elucidated in several studies on young healthy men, showing reproducible interindividual differences ranging from varying degrees of inhibition to no significant change, with very few subjects showing significant excitation. These individual response patterns have been shown to predict the neural response to mental stress and coupled blood pressure responses. The aim of this study was to investigate whether premenopausal healthy women show similar neural and blood pressure responses. Muscle sympathetic nerve recordings from the peroneal nerve were performed in 34 healthy women (mean age 27 ± 8 yr) during sudden sensory stimuli (electrical stimuli to a finger) and 3 min of mental stress (forced arithmetics). After sensory stimuli, 18 women showed varying degrees of inhibition of muscle sympathetic nerve activity (burst amplitude mean reduction 60%, range 34-100%). The remaining 16 showed no inhibition (mean 5%, range -31 to 28%; one subject exhibiting excitation). During 3 min of mental stress, the normalized change in burst incidence for muscle sympathetic nerve activity correlated with the percentage change of muscle sympathetic nerve activity induced by the sensory stimulation protocol (r = 0.64, P = 0.0042). In contrast to men, the neural responses did not predict changes in blood pressure. Thus, premenopausal females show a similar range of individual differences in defense-related muscle sympathetic neural responses as men, but no associated differences in blood pressure responses. Whether these patterns are unchanged after menopause remains to be investigated.NEW & NOTEWORTHY Muscle sympathetic neural responses to sudden sensory stimuli in premenopausal women showed interindividual differences and the distribution of sympathetic responses was similar to that previously found in men. Despite this similarity, the associated differences in transient blood pressure responses seen in men were not found in women. The increased risk of developing hypertension in postmenopausal women warrants an investigation of whether these response patterns are altered after menopause.

Nature-Based Therapeutic Intervention for Individuals with Post-Concussion Symptoms.

This study investigated the efficacy of a 10-session nature-based therapeutic intervention for people with post-concussion symptoms. The intervention involved physical and vestibular exercises, sensory training, relaxation, and psychoeducation, all of which were integrated with the natural environment in a forest therapy garden. This study was designed with a passive control period followed by the intervention (n = 30). The Mental Fatigue Scale (MFS) was the primary outcome measure. The secondary outcome measures were the Warwick-Edinburg Mental Wellbeing Scale and the short version of the Quality of Life after Brain Injury. A Likert scale was used to examine the mental strain of the sessions themselves. The MFS (primary outcome) exhibited a significant decrease with a medium-sized effect from before to after the intervention. The secondary outcomes exhibited significant increases from the beginning to the end of the intervention. All outcomes were sustained at follow-up ten weeks later. No significant difference was found from the control period. This study indicates that the described nature-based intervention is a feasible treatment for reducing prolonged post-concussion symptoms. However, it should be studied more in-depth to understand the impact of the natural environment and to validate the results on a larger representative population.

Proprioception enhancement for robot assisted neural rehabilitation: a dynamic electrical stimulation based method and preliminary results from EEG analysis.

Objective.In recent years, the robot assisted (RA) rehabilitation training has been widely used to counteract defects of the manual one provided by physiotherapists. However, since the proprioception feedback provided by the robotic assistance or the manual methods is relatively weak for the paralyzed patients, their rehabilitation efficiency is still limited. In this study, a dynamic electrical stimulation (DES) based proprioception enhancement and the associated quantitative analysis methods have been proposed to overcome the limitation mentioned above.Approach.Firstly, the DES based proprioception enhancement method was proposed for the RA neural rehabilitation. In the method, the relationship between the surface electromyogram (sEMG) envelope of the specified muscle and the associated joint angles was constructed, and the electrical stimulation (ES) pulses for the certain joint angles were designed by consideration of the corresponding sEMG envelope, based on which the ES can be dynamically regulated during the rehabilitation training. Secondly, power spectral density, source estimation, and event-related desynchronization of electroencephalogram, were combinedly used to quantitatively analyze the proprioception from multiple perspectives, based on which more comprehensive and reliable analysis results can be obtained. Thirdly, four modes of rehabilitation training tasks, namely active, RA, DES-RA, and ES-only training, were designed for the comparison experiment and validation of the proposed DES based proprioception enhancement method.Main results.The results indicated that the activation of the sensorimotor cortex was significantly enhanced when the DES was added, and the cortex activation for the DES-RA training was similar to that for the active training. Meanwhile, relatively consistent results from the multiple perspectives were obtained, which validates the effectiveness and robustness of the proposed proprioception analysis method.Significance.The proposed methods have the potential to be applied in the practical rehabilitation training to improve the rehabilitation efficiency.

The impact of physical therapy on dysphagia in neurological diseases: a review.

A neurogenic dysphagia is dysphagia caused by problems with the central and peripheral nervous systems, is particularly prevalent in conditions such as Parkinson's disease and stroke. It significantly impacts the quality of life for affected individuals and causes additional burdens, such as malnutrition, aspiration pneumonia, asphyxia, or even death from choking due to improper eating. Physical therapy offers a non-invasive treatment with high efficacy and low cost. Evidence supporting the use of physical therapy in dysphagia treatment is increasing, including techniques such as neuromuscular electrical stimulation, sensory stimulation, transcranial direct current stimulation, and repetitive transcranial magnetic stimulation. While initial studies have shown promising results, the effectiveness of specific treatment regimens still requires further validation. At present, there is a lack of scientific evidence to guide patient selection, develop appropriate treatment regimens, and accurately evaluate treatment outcomes. Therefore, the primary objectives of this review are to review the results of existing research, summarize the application of physical therapy in dysphagia management, we also discussed the mechanisms and treatments of physical therapy for neurogenic dysphagia.

Unlocking the potential of 'passive' modulation: How sensory stimulation shapes hand and face size.

Knowledge of the body size is intricately tied to multisensory integration processes that rely on the dynamic interplay of top-down and bottom-up mechanisms. Recent years have seen the development of passive sensory stimulation protocols aimed at investigating the modulation of various cognitive functions, primarily inducing perceptual learning and behaviour change without the need for extensive training. Given that reductions in sensory input have been associated with alterations in body size perception, it is reasonable to hypothesize that increasing sensory information through passive sensory stimulation could similarly influence the perception of the size of body parts. The primary aim of this study was to investigate the potential modulatory effects of passive sensory stimulation on the perception of hand and face size in a group of young adults. Passive sensory stimulation effectively modulated the size representation of the stimulated hand, supporting the notion that access to somatosensory and proprioceptive information is prioritised for the hands but may not extend to the face. Increased somatosensory input resulted in a reduction of distortion, providing evidence for bottom-up modulation of size representation. Passive sensory stimulation can induce subjective changes in body size perception without the need for extensive training. This paradigm holds promise as a potential alternative for modulating distorted size representation in individuals with body representational deficits.

Alternating bilateral sensory stimulation alleviates alcohol-induced conditioned place preference via a superior colliculus-VTA circuit.

Alcohol is the most widely used addictive substance, potentially leading to brain damage and genetic abnormalities. Despite its prevalence and associated risks, current treatments have yet to identify effective methods for reducing cravings and preventing relapse. In this study, we find that 4-Hz alternating bilateral sensory stimulation (ABS) effectively reduces ethanol-induced conditioned place preference (CPP) in male mice, while 4-Hz flash light does not exhibit therapeutic effects. Whole-brain c-Fos mapping demonstrates that 4-Hz ABS triggers notable activation in superior colliculus GABAergic neurons (SCGABA). SCGABA forms monosynaptic connections with ventral tegmental area dopaminergic neurons (VTADA), which is implicated in ethanol-induced CPP. Bidirectional chemogenetic manipulation of SC-VTA circuit either replicates or blocks the therapeutic effects of 4-Hz ABS on ethanol-induced CPP. These findings elucidate the role of SC-VTA circuit for alleviating ethanol-related CPP by 4-Hz ABS and point to a non-drug and non-invasive approach that might have potential for treating alcohol use disorder.

Mechanosensory bristles mediate avoidance behavior by triggering sustained local motor activity in Drosophila melanogaster.

During locomotion, most vertebrates-and invertebrates such as Drosophila melanogaster-are able to quickly adapt to terrain irregularities or avoid physical threats by integrating sensory information along with motor commands. Key to this adaptability are leg mechanosensory structures, which assist in motor coordination by transmitting external cues and proprioceptive information to motor centers in the central nervous system. Nevertheless, how different mechanosensory structures engage these locomotor centers remains poorly understood. Here, we tested the role of mechanosensory structures in movement initiation by optogenetically stimulating specific classes of leg sensory structures. We found that stimulation of leg mechanosensory bristles (MsBs) and the femoral chordotonal organ (ChO) is sufficient to initiate forward movement in immobile animals. While the stimulation of the ChO required brain centers to induce forward movement, unexpectedly, brief stimulation of leg MsBs triggered a fast response and sustained motor activity dependent only on the ventral nerve cord (VNC). Moreover, this leg-MsB-mediated movement lacked inter- and intra-leg coordination but preserved antagonistic muscle activity within joints. Finally, we show that leg-MsB activation mediates strong avoidance behavior away from the stimulus source, which is preserved even in the absence of a central brain. Overall, our data show that mechanosensory stimulation can elicit a fast motor response, independently of central brain commands, to evade potentially harmful stimuli. In addition, it sheds light on how specific sensory circuits modulate motor control, including initiation of movement, allowing a better understanding of how different levels of coordination are controlled by the VNC and central brain locomotor circuits.

Sensory integration for neuroprostheses: from functional benefits to neural correlates.

In the field of sensory neuroprostheses, one ultimate goal is for individuals to perceive artificial somatosensory information and use the prosthesis with high complexity that resembles an intact system. To this end, research has shown that stimulation-elicited somatosensory information improves prosthesis perception and task performance. While studies strive to achieve sensory integration, a crucial phenomenon that entails naturalistic interaction with the environment, this topic has not been commensurately reviewed. Therefore, here we present a perspective for understanding sensory integration in neuroprostheses. First, we review the engineering aspects and functional outcomes in sensory neuroprosthesis studies. In this context, we summarize studies that have suggested sensory integration. We focus on how they have used stimulation-elicited percepts to maximize and improve the reliability of somatosensory information. Next, we review studies that have suggested multisensory integration. These works have demonstrated that congruent and simultaneous multisensory inputs provided cognitive benefits such that an individual experiences a greater sense of authority over prosthesis movements (i.e., agency) and perceives the prosthesis as part of their own (i.e., ownership). Thereafter, we present the theoretical and neuroscience framework of sensory integration. We investigate how behavioral models and neural recordings have been applied in the context of sensory integration. Sensory integration models developed from intact-limb individuals have led the way to sensory neuroprosthesis studies to demonstrate multisensory integration. Neural recordings have been used to show how multisensory inputs are processed across cortical areas. Lastly, we discuss some ongoing research and challenges in achieving and understanding sensory integration in sensory neuroprostheses. Resolving these challenges would help to develop future strategies to improve the sensory feedback of a neuroprosthetic system.

Repetitive peripheral sensory stimulation for motor recovery after stroke: a scoping review.

BACKGROUND AND PURPOSE: Enhancing afferent information from the paretic limb can improve post-stroke motor recovery. However, uncertainties exist regarding varied sensory peripheral neuromodulation protocols and their specific impacts. This study outlines the use of repetitive peripheral sensory stimulation (RPSS) and repetitive magnetic stimulation (rPMS) in individuals with stroke. METHODS: This scoping review was conducted according to the JBI Evidence Synthesis guidelines. We searched studies published until June 2023 on several databases using a three-step analysis and categorization of the studies: pre-analysis, exploration of the material, and data processing. RESULTS: We identified 916 studies, 52 of which were included (N = 1,125 participants). Approximately 53.84% of the participants were in the chronic phase, displaying moderate-to-severe functional impairment. Thirty-two studies used RPSS often combining it with task-oriented training, while 20 used rPMS as a standalone intervention. The RPSS primarily targeted the median and ulnar nerves, stimulating for an average of 92.78 min at an intensity that induced paresthesia. RPMS targeted the upper and lower limb paretic muscles, employing a 20 Hz frequency in most studies. The mean stimulation time was 12.74 min, with an intensity of 70% of the maximal stimulator output. Among the 114 variables analyzed in the 52 studies, 88 (77.20%) were in the "s,b" domain, with 26 (22.8%) falling under the "d" domain of the ICF. DISCUSSION AND CONCLUSION: Sensory peripheral neuromodulation protocols hold the potential for enhancing post-stroke motor recovery, yet optimal outcomes were obtained when integrated with intensive or task-oriented motor training.

Decreasing the incidence of delirium via multi-sensory stimulation in patients receiving mechanical ventilation in the intensive care unit: A protocol for a randomized feasibility study.

Introduction: Delirium is a common acute brain dysfunction syndrome in patients admitted to intensive care units (ICUs). Family engagement strategies, based on the theory of multi-sensory stimulation to ameliorate sensory deprivation in patients, may be an effective and scalable method to reduce the burden of delirium. Methods: /design: This is a assessor-blinded, randomised controlled trial of the feasibility of multi-sensory stimulation (MS) in patients with delirium. A total of 72 mechanically ventilated patients (n = 24 in each group) admitted to the ICU will be randomised to routine non-pharmacological delirium care (control), family multi-sensory stimulation and nurse multi-sensory stimulation groups. All participants except the control group will receive multi-sensory stimulation, including visual, auditory, tactile and kinesthetic stimulation, for 5 days. Our primary aim is to determine the feasibility of the study procedure (recruitment, eligibility, retention and attrition rates, appropriateness of clinical outcome measures), feasibility, acceptability and safety of the intervention (adverse events, satisfaction and other). Our secondary objective is to assess the preliminary efficacy of the MS protocol in reducing the incidence, duration and severity of delirium. Sedation levels and delirium severity will be assessed twice daily. Enrolled participants will be followed in hospital until death, discharge or up to 28 days after treatment. Ethics and dissemination: The current study was approved by the Ethics Review Board of Huazhong University of Science and Technology Union Shenzhen Hospital, China (KY-2023-031-01). The results of this study will be presented at scientific conferences and submitted for publication in peer-reviewed journals. Trial registration number: ChiCTR2300071457.

Influencing dreams through sensory stimulation: A systematic review.

Sleep is typically considered a state of disconnection from the environment, yet instances of external sensory stimuli influencing dreams have been reported for centuries. Explaining this phenomenon could provide valuable insight into dreams' generative and functional mechanisms, the factors that promote sleep continuity, and the processes that underlie conscious awareness. Moreover, harnessing sensory stimuli for dream engineering could benefit individuals suffering from dream-related alterations. This PRISMA-compliant systematic review assessed the current evidence concerning the influence of sensory stimulation on sleep mentation. We included 51 publications, of which 21 focused on auditory stimulation, ten on somatosensory stimulation, eight on olfactory stimulation, four on visual stimulation, two on vestibular stimulation, and one on multimodal stimulation. Furthermore, nine references explored conditioned associative stimulation: six focused on targeted memory reactivation protocols and three on targeted lucid reactivation protocols. The reported frequency of stimulus-dependent dream changes across studies ranged from 0 to ∼80%, likely reflecting a considerable heterogeneity of definitions and methodological approaches. Our findings highlight a lack of comprehensive understanding of the mechanisms, functions, and neurophysiological correlates of stimulus-dependent dream changes. We suggest that a paradigm shift is required for meaningful progress in this field.

Audiovisual gamma stimulation for the treatment of neurodegeneration.

Alzheimer's disease (AD) is the most common type of neurodegenerative disease and a health challenge with major social and economic consequences. In this review, we discuss the therapeutic potential of gamma stimulation in treating AD and delve into the possible mechanisms responsible for its positive effects. Recent studies reveal that it is feasible and safe to induce 40 Hz brain activity in AD patients through a range of 40 Hz multisensory and noninvasive electrical or magnetic stimulation methods. Although research into the clinical potential of these interventions is still in its nascent stages, these studies suggest that 40 Hz stimulation can yield beneficial effects on brain function, disease pathology, and cognitive function in individuals with AD. Specifically, we discuss studies involving 40 Hz light, auditory, and vibrotactile stimulation, as well as noninvasive techniques such as transcranial alternating current stimulation and transcranial magnetic stimulation. The precise mechanisms underpinning the beneficial effects of gamma stimulation in AD are not yet fully elucidated, but preclinical studies have provided relevant insights. We discuss preclinical evidence related to both neuronal and nonneuronal mechanisms that may be involved, touching upon the relevance of interneurons, neuropeptides, and specific synaptic mechanisms in translating gamma stimulation into widespread neuronal activity within the brain. We also explore the roles of microglia, astrocytes, and the vasculature in mediating the beneficial effects of gamma stimulation on brain function. Lastly, we examine upcoming clinical trials and contemplate the potential future applications of gamma stimulation in the management of neurodegenerative disorders.