Exploring the reliability and validity of clinically-relevant outcome measures for chemotherapy-induced peripheral neuropathy.

PURPOSE: To explore the reliability and validity of clinically-relevant outcome measures for balance (i.e., The Short Physical Performance Battery [SPPB] - Balance Subscale) and sensation (i.e., monofilament threshold testing) for use in clinical trials of chemotherapy-induced peripheral neuropathy (CIPN). METHODS: Adult, post-treatment cancer survivors (N = 142) who had reported ≥ 4/10 CIPN symptom severity following neurotoxic chemotherapy were recruited from six National Cancer Institute Community Oncology Research Program (NCORP) sites associated with the University of Rochester Cancer Center NCORP Research Base. Participants completed the monofilament threshold test at the screening and baseline time points (i.e., one week apart), while the Quality of Life Questionnaire-CIPN20, Treatment-Induced Neuropathy Assessment Scale, and SPPB - Balance Subscale were completed at baseline. Test-retest reliability of the monofilament threshold testing scores was assessed using the Intraclass Correlation Coefficient (ICC). The convergent validity among monofilament threshold testing, SPPB - Balance Subscale, and CIPN patient-reported outcome (PRO) scores at baseline was assessed using Spearman's correlation. RESULTS: Ceiling effects were observed for SPPB-Balance Subscale scores as 113 (79.6%) respondents reported the highest score. Agreement between the screening and baseline monofilament threshold testing scores was moderate (ICC = 0.65). Monofilament threshold testing (rs Range: 0.14 - 0.21) and SPPB Balance Subscale scores (rs Range: -0.36 - -0.22) showed largely low correlations with all PRO measures. CONCLUSIONS: Monofilament threshold testing demonstrated moderate test-retest reliability, but low convergent validity with CIPN PROs, while the SPPB - Balance Subscale demonstrated low convergent validity with CIPN PROs and ceiling effects (i.e., highest possible score) among post-treatment cancer survivors with CIPN. Future research is needed to identify promising measures of balance and sensation loss for use in clinical trials that complement CIPN PROs to aid in the identification of clinically relevant treatments for CIPN. TRIAL REGISTRATION: NCT04367490 [April 29, 2020].

The interactive walkway provides fit-for-purpose fall-risk biomarkers in the elderly: Comparison of zolpidem and suvorexant.

Dynamic balance assessments such as walking adaptability may yield a more realistic prediction of drug-induced falls compared with postural stability measurements, as falls often result from limited gait adjustments when walking. The Interactive Walkway (IWW) measures walking adaptability but sensitivity to medication effects is unknown. If proven sensitive and specific, IWW could serve as a biomarker for targeted fall-risk assessments in early clinical drug development. In this three-way crossover study, 18 healthy elderly (age: 65-80 years) subjects received 5 mg zolpidem, 10 mg suvorexant, or placebo in the morning. Assessments were performed pre-dose and approximately hourly until 9 h post-dose. IWW assessments included an 8-meter walking test, goal-directed stepping, obstacle-avoidance, and tandem-walking. Other pharmacodynamic measurements were the Timed-Up-and-Go (TUG) test at a comfortable and fast pace, adaptive tracking, and body sway. A decline in performance was observed for zolpidem compared with placebo for 3 h post-dose in IWW walking adaptability outcome measures, TUG, adaptive tracking, and body sway. For the IWW tasks, a decrease in walking speed (among others) was observed. IWW parameters were not affected by suvorexant compared with placebo at any timepoint. However, an increase of 9.8% (95%CI: 1.8%, 18.5%) in body sway was observed for suvorexant compared with placebo up to 3 h post-dose. The IWW successfully quantified drug effects of two hypnotic drugs and distinguished between zolpidem and suvorexant regarding their effects on walking. As a biomarker, the IWW demonstrated sensitivity in assessing dynamic balance and potential fall risk in early phase clinical drug development.

Microplastic polyethylene induced inner ear dysfunction in murine model.

While the hazardous effects of microplastics (MPs) are increasingly reported, it remains uncertain if MPs induce inner ear dysfunction. Nonetheless, prevalence of inner ear dysfunction was observed across all age groups. In this study, we investigated whether MP polyethylene affect inner ear function in a murine model. To detect hearing loss and balance defect after polyethylene (PE) exposure, we evaluated hearing threshold levels, assessed cerebral glucose metabolism, conducted transcriptome analysis, and performed behavioral studies. C57BL/6 J mice (5-week-old) were grouped into control (n = 10) and PE-fed groups (n = 10). Mice were orally administered 100 ppm/100 µL (equivalent to 10 µg) of PE every day for 4 months. We identified the accumulation of PE in the cochlea and vestibular region. The fragmented PE in inner ear was 3.00 ± 0.38 µm in size; the administered PE concentration was 1.14 ± 1.06 mg/g. Fourier transform infrared spectrometry confirmed that the properties of the MP were identical with those of PE fed to the mice. Transcriptomic analysis showed up-regulation of PER1, NR4A3 and CEBPB at the PE exposed inner ear tissue and it was confirmed using qRT-PCR, western blotting, and immunofluorescence staining. We observed abnormalities in balance related behavior assessment in the PE group. Exposure to PE increased the hearing thresholds and decreased glucose metabolism in the bilateral lateral entorhinal cortex, right primary auditory cortex, and right secondary auditory cortex. We can conclude that PE exposure induced inner ear dysfunction such as hearing loss and balance disorder.

Chemotherapy-Induced Peripheral Neuropathy and Falls in Cancer Survivors Relate to Digital Balance and Gait Impairments.

PURPOSE: Chemotherapy-induced peripheral neuropathy (CIPN) and falls can be persistent side effects of cancer treatment. Standing postural sway and gait tests with body-worn, inertial sensors provide objective digital balance and gait measures that represent several different domains controlling mobility. Specific domains of balance and gait that related to neuropathy and falls are unknown. The aim of this study was to determine which domains of balance and gait differed between cancer survivors who report (1) CIPN symptoms versus no symptoms, (2) a history of falls in the past 6 months versus no falls, and (3) prospective falls over 12 months versus no falls. METHODS: Postural sway during 30 seconds of quiet standing and gait characteristics from a 7-m timed up and go test were recorded with six synchronized inertial sensors (Opals by APDM Wearable Technologies, a Clario Company) in 425 older, female cancer survivors (age: 62 ± 6 years). A principal component analysis (PCA) approach was used to identify independent domains of mobility from 15 balance and gait measures. RESULTS: PCA analysis revealed five independent domains (PC1 = sway amplitude, PC2 = gait pace, PC3 = sway frequency, PC4 = gait spatial-temporal, and PC5 = turning) that accounted for 81% of the variance of performance. Cancer survivors who reported CIPN symptoms had significantly higher sway frequency (PC3) than asymptomatic survivors. Past fallers had significantly larger sway area (PC1) and slower gait pace (PC2) than nonfallers. Prospective fallers showed a significantly smaller stride length (PC4) than nonfallers. CONCLUSION: Digital balance and gait measures using wearable sensors during brief standing and walking tests provide objective metrics of CIPN-related mobility impairment and fall risk that could be useful for oncology clinical trials.

Caffeine Improves Sprint Time in Simulated Freestyle Swimming Competition but Not the Vertical Jump in Female Swimmers.

Caffeine (CAF) has been shown to be an effective ergogenic aid in enhancing sports performance, including vertical jump (VJ), sprint, balance, agility, and freestyle swimming performance (FSP). However, whether acute CAF supplementation improves FSP in moderately trained female swimmers has not been well documented. Therefore, this study aimed to investigate the effects of CAF intake on vertical jump, balance, auditory reaction time (ART), and swimming performance in female swimmers. In a double-blind, cross-over design, eight moderately trained female swimmers (age: 21.3 ± 1.4 years, height: 161.2 ± 7.1 cm, body mass: 56.3 ± 6.7 kg, body mass index (BMI): 21.9 ± 1.3 kg/m2, and habitual CAF intake: 246.4 ± 111.4 mg/day) ingested caffeine (CAF) (6 mg/kg) or a placebo (PLA) 60 min before completing VJ, balance, ART, and 25/50 m FSP. CAF supplementation resulted in a significantly lower time both in 25m (p = 0.032) and 50m (p = 0.033) FSP. However, CAF resulted in no significant difference in VJ, ART, and RPE (p > 0.05). Balance test results showed a non-significant moderate main effect (d = 0.58). In conclusion, CAF seems to reduce time in short-distance swimming performances, which could be the determinant of success considering the total time of the race. Thus, we recommend coaches and practitioners incorporate CAF into swimmers' nutrition plans before competitions, which may meet the high performance demands.

Amelioration of gait and balance disorders by rosuvastatin is associated with changes in cerebrovascular reactivity in older patients with hypertensive treatment.

To investigate the effect of rosuvastatin on gait and balance disorder progression and elucidate the role of cerebrovascular reactivity (CVR) on this effect. From April 2008 to November 2010, 943 hypertensive patients aged ≥60 years were enrolled from the Shandong area of China. Patients were randomized into rosuvastatin and placebo groups. Gait, balance, CVR, fall and stroke were assessed. During an average 72 months of follow-up, the decreasing trends for step length, step speed, and Berg balance scale scores and the increasing trends for step width and chair rising test were slower in the rosuvastatin group when compared to the placebo group. The hazard ratio of incident balance impairment and falls was 0.542 [95% confidence interval (CI) 0.442-0.663] and 0.532 (95% CI 0.408-0.694), respectively, in the rosuvastatin group compared with placebo group. For CVR progression, the cerebrovascular reserve capacity and breath-holding index were increased and the pulsatility index decreased in the rosuvastatin group, while the cerebrovascular reserve capacity and breath-holding index were decreased, and pulsatility index increased in the placebo group. The changes in gait stability and balance function were independently associated with the changes in the CVR. The odds risks of balance impairment and falls were 2.178 (95% CI: 1.491-3.181) and 3.227 (95% CI: 1.634-6.373), respectively, in the patients with CVR impairment and patients without CVR impairment. Rosuvastatin ameliorated gait and balance disorder progression in older patients with hypertension. This effect might result from the improvement in the CVR. This double-blind clinical trial recruited 943 hypertensive patients aged ≥60 years who were randomly administered rosuvastatin and placebo interventions. The data indicates that rosuvastatin significantly ameliorated the progressions of gait and balance disorders in older hypertensive patients. The cerebrovascular reactivity might play an important mediating role in this amelioration.

Probing polypharmacy, ageing and sex effects on physical function using different tests.

BACKGROUND: Ageing, sex and polypharmacy affect physical function. OBJECTIVES: This mouse study investigates how ageing, sex and polypharmacy interact and affect grip strength, balance beam and wire hang, correlating and comparing the different test results between and within subgroups. METHODS: Young (2.5 months) and old (21.5 months) C57BL/6 J male and female mice (n = 10-6/group) were assessed for physical function at baseline on grip strength, balance beam and wire hang with three trials of 60 s (WH60s) and one trial of 300 s (WH300s). Mice were randomised to control or diet containing a high Drug Burden Index (DBI, total anticholinergic and sedative drug exposure) polypharmacy regimen (metoprolol, simvastatin, citalopram, oxycodone and oxybutynin at therapeutic oral doses). Following 6-8 weeks of treatment, mice were reassessed. RESULTS: High DBI polypharmacy and control mice both showed age group differences on all tests (p < 0.05). Only control mice showed sex differences, with females outperforming males on the WH60s and balance beam for old mice, WH300s for young mice (p < 0.05). Polypharmacy reduced grip strength in all subgroups (p < 0.05) and only in old females reduced wire hang time and cumulative behaviour and balance beam time and %walked (p < 0.05). Physical function assessments were all correlated with each other, with differences between subgroups (p < 0.05), and mice within subgroups showed interindividual variability in performance. CONCLUSION: Age, sex and polypharmacy have variable effects on different tests, and behavioural measures are useful adjuvants to assessing performance. There was considerable within-group variability in change in measures over time. These findings can inform design and sample size of future studies.

Neuroprotective effects of indole-3-carbinol on the rotenone rat model of Parkinson's disease: Impact of the SIRT1-AMPK signaling pathway.

Parkinson's disease (PD) is the second most common progressive neurodegenerative disorder. Although mounting studies have been conducted, no effective therapy is available to halt its progression. Indole-3-carbinol (I3C) is a naturally occurring compound obtained by ß-thioglucosidase-mediated autolysis of glucobrassicin in cruciferous vegetables. Besides its powerful antioxidant activity, I3C has shown neuroprotection against depression and chemically induced neurotoxicity via its anti-inflammatory and antiapoptotic effects. This study aimed to investigate the neuroprotective effects of I3C against rotenone (ROT)-induced PD in male albino rats. The possible protective mechanisms were also explored. PD was induced by subcutaneous administration of ROT (2 mg/kg) for 28 days. The effects of I3C (25, 50, and 100 mg/kg/day) were assessed by catalepsy test (bar test), spontaneous locomotor activity, rotarod test, weight change, tyrosine hydroxylase (TH) expression, α-synuclein (α-Syn) expression, striatal dopamine (DA) content, and histological examination. The highest dose of I3C (100 mg/kg) was the most effective to prevent ROT-mediated motor dysfunctions and amend striatal DA decrease, weight loss, neurodegeneration, TH expression reduction, and α-Syn expression increase in both the midbrain and striatum. Further mechanistic investigations revealed that the neuroprotective effects of I3C are partially attributed to its anti-inflammatory and antiapoptotic effects and the activation of the sirtuin 1/AMP-activated protein kinase pathway. Altogether, these results suggested that I3C could attenuate biochemical, molecular, and functional changes in a rat PD model with following repeated rotenone exposures.

Temporal dynamics of cortical activity and postural control in response to the first levodopa dose of the day in people with Parkinson's disease.

BACKGROUND: Our understanding of how balance control responds to levodopa over the course of a single day in people with Parkinson's disease (PD) is limited with the majority of studies focused on isolated comparisons of ON vs. OFF levodopa medication. OBJECTIVE: To evaluate the temporal dynamics of postural control following the first levodopa dose of the day during a challenging standing task in a group of people with PD. METHODS: Changes in postural control were evaluated by monitoring cortical activity (covering frontal, motor, parietal and occipital areas), body sway parameters (force platform), and lower limb muscle activity (tibialis anterior and gastrocnemius medialis) in 15 individuals with PD during a semi-tandem standing task. Participants were assessed during two 60 second trials every 30 minutes (ON-30 ON-60 etc.) for 3 hours after the first matinal dose (ON-180). RESULTS: Compared to when tested OFF-medication, cortical activity was increased across all four regions from ON-60 to ON-120 with early increases in alpha and beta band activity observed at ON-30. Levodopa was associated with increased gastrocnemius medialis activity (ON-30 to ON-120) and ankle co-contraction (ON-60 to ON-120). Changes in body sway outcomes (particularly in the anterior-posterior direction) were evident from ON-60 to ON-120. CONCLUSIONS: Our results reveal a 60-minute window within which postural control outcomes may be obtained that are different compared to OFF-state and remain stable (from 60-minutes to 120-minutes after levodopa intake). Identifying a window of opportunity for measurement when individuals are optimally medicated is important for observations in a clinical and research setting.

Effect of baduanjin on the fall and balance function in middle-aged and elderly people: A protocol for systematic review and meta-analysis.

BACKGROUND: The risk of fall seriously affects the health and quality of life of the middle-aged and elderly people, especially the injury and disability caused by fall of the middle-aged and elderly people, which imposes a huge burden on family and social medical care. Baduanjin exercise may be an effective intervention to enhance the muscle strength and stability of lower limbs, improve the balance ability and gait of middle-aged and elderly people, reduce the incidence of falls, improve the quality of life, and promote the health of middle-aged and elderly people. The aim of this study is to summarize evidence and systematically review the efficacy and safety of Baduanjin on the fall and balance function in middle-aged and elderly people. METHODS: We conducted a systematic search of English and Chinese RCTs in the following 8 electronic databases: PubMed, EMBASE, Web of Science, The Cochrane Library, Chinese Biomedical Literature Database (CBM), Chinese National Knowledge Infrastructure (CNKI), Chinese Science and Technology Periodical Database (VIP), Wanfang Database, from their respective dates of inception to July 2021. Other resources will be searched if necessary. The primary outcome is the fall rate in middle-aged and elderly people and the secondary outcomes include the Single-Leg Standing (SLS) Test, Berg Balance Scale (BBS), Timed Up and Go (TUG) Test. The study selection, data extraction, risk of bias, data synthesis and analysis, reporting biases, and the quality of evidence will be independently conducted by 2 reviewers who use the EndNote X9 software, Cochrane handbook assessment tool, RevMan 5.3 software, a funnel plot and GRADE system. RESULTS: This study will evaluate the effect of Baduanjin on falls and balance function of middle-aged and elderly people from multiple outcome evaluation indicators such as fall rate, and provide high-quality evidence. CONCLUSION: This study will provide evidence for whether Baduanjin has an effect on falls and balance function in middle-aged and elderly people. ETHICS AND DISSEMINATION: Ethics approval is not required for systematic review, since it does not infringe on personal interests. The results will be submitted to peer-review journals or disseminated at scientific conferences.

Restoration of HDAC1 Enzymatic Activity after Stroke Protects Neurons from Ischemia/Reperfusion Damage and Attenuates Behavioral Deficits in Rats.

A therapeutic approach for promoting neuroprotection and brain functional regeneration after strokes is still lacking. Histone deacetylase 1 (HDAC1), which belongs to the histone deacetylase family, is involved in the transcriptional repression of cell-cycle-modulated genes and DNA damage repair during neurodegeneration. Our previous data showed that the protein level and enzymatic activity of HDAC1 are deregulated in stroke pathogenesis. A novel compound named 5104434 exhibits efficacy to selectively activate HDAC1 enzymatic function in neurodegeneration, but its potential in stroke therapy is still unknown. In this study, we adopted an induced rat model with cerebral ischemia using the vessel dilator endothelin-1 to evaluate the potential of compound 5104434. Our results indicated compound 5104434 selectively restored HDAC1 enzymatic activity after oxygen and glucose deprivation, preserved neurite morphology, and protected neurons from ischemic damage in vitro. In addition, compound 5104434 attenuated the infarct volume, neuronal loss, apoptosis, DNA damage, and DNA breaks in cerebral ischemia rats. It further ameliorated the behavioral outcomes of neuromuscular response, balance, forepaw strength, and functional recovery. Collectively, our data support the efficacy of compound 5104434 in stroke therapy and contend that it can be considered for clinical trial evaluation.

Effects of Caffeine Ingestion on Human Standing Balance: A Systematic Review of Placebo-Controlled Trials.

Caffeine ingestion may influence balance control via numerous mechanisms. Although previously investigated using various study designs and methods, here we aimed to create the first evidence-based consensus regarding the effects of caffeine on the control of upright stance via systematic review (PROSPERO registration CRD42021226939). Embase, PubMed/MEDLINE, SPORTDiscus and Web of Science databases were searched on 27 January 2021 to identify placebo-controlled trials investigating caffeine-induced changes in human standing balance. Reference lists of eligible studies were also searched. Overall, nine studies involving a total of 290 participants were included. All studies were moderate to strong in quality according to the QualSyst tool. Balance-related outcome measures were collected across a range of different participant ages, stances and sensory conditions. The results show that younger participants' balance was generally unaffected by caffeine ingestion. However, a significant balance impairment was observed following caffeine ingestion in all studies involving older participants (average age >65 years). Our results therefore suggest an age-dependent effect of caffeine ingestion on human standing. Further research into this effect is warranted as only one study has directly compared younger and older adults. Nonetheless, an important implication of our findings is that caffeine ingestion may increase fall risk in older adults. Furthermore, based on our findings, caffeine ingestion should be considered as a potential confounding factor when assessing human standing balance, particularly in older adults.

Cannabidiol reduces lesion volume and restores vestibulomotor and cognitive function following moderately severe traumatic brain injury.

Despite the high incidence of traumatic brain injury (TBI), there is no universal treatment to safely treat patients. Blunt brain injuries destroy primary neural tissue that results in impaired perfusion, excessive release of glutamate, inflammation, excitotoxicity, and progressive secondary neuronal cell death. We hypothesized that administration of cannabidiol (CBD) directly to a brain contusion site, will optimize delivery to the injured tissue which will reduce local neural excitation and inflammation to spare neural tissue and improve neurological outcome following TBI. CBD was infused into a gelfoam matrix forming an implant (CBDi), then applied over the dura at the contusion site as well as delivered systemically by injection (CBD.IP). Post-injury administration of CBDi+IP greatly reduced defecation scores, lesion volume, the loss of neurons in the ipsilateral hippocampus, the number of injured neurons of the contralateral hippocampus, and reversed TBI-induced glial fibrillary acidic protein (GFAP) upregulation which was superior to either CBD.IP or CBDi treatment alone. Vestibulomotor performance on the beam-balance test was restored by 12 days post-TBI and sustained through 28 days. CBDi+IP treated rats exhibited preinjury levels of spontaneous alternation on the spontaneous alternation T-maze. In the object recognition test, they had greater mobility and exploration of novel objects compared to contusion or implant alone consistent with reduced anxiety and restored cognitive function. These results suggest that dual therapy by targeting the site of injury internally with a CBD-infused medical carrier followed by systemic supplementation may offer a more effective countermeasure than systemic or implant treatment alone for the deleterious effects of penetrating head wounds.

Early balance impairment in Parkinson's Disease: Evidence from Robot-assisted axial rotations.

OBJECTIVE: Early postural instability (PI) is a red flag for the diagnosis of Parkinson's disease (PD). Several patients, however, fall within the first three years of disease, particularly when turning. We investigated whether PD patients, without clinically overt PI, manifest abnormal reactive postural responses to ecological perturbations resembling turning. METHODS: Fifteen healthy subjects and 20 patients without clinically overt PI, under and not under L-Dopa, underwent dynamic posturography during axial rotations around the longitudinal axis, provided by a robotic mechatronic platform. We measured reactive postural responses, including body displacement and reciprocal movements of the head, trunk, and pelvis, by using a network of three wearable inertial sensors. RESULTS: Patients showed higher body displacement of the head, trunk and pelvis, and lower joint movements at the lumbo-sacral junction than controls. Conversely, movements at the cranio-cervical junction were normal in PD. L-Dopa left reactive postural responses unchanged. CONCLUSIONS: Patients with PD without clinically overt PI manifest abnormal reactive postural responses to axial rotations, unresponsive to L-Dopa. The biomechanical model resulting from our experimental approach supports novel pathophysiological hypotheses of abnormal axial rotations in PD. SIGNIFICANCE: PD patients without clinically overt PI present subclinical balance impairment during axial rotations, unresponsive to L-Dopa.

Breaking a dogma: acute anti-inflammatory treatment alters both post-lesional functional recovery and endogenous adaptive plasticity mechanisms in a rodent model of acute peripheral vestibulopathy.

BACKGROUND: Due to their anti-inflammatory action, corticosteroids are the reference treatment for brain injuries and many inflammatory diseases. However, the benefits of acute corticotherapy are now being questioned, particularly in the case of acute peripheral vestibulopathies (APV), characterized by a vestibular syndrome composed of sustained spinning vertigo, spontaneous ocular nystagmus and oscillopsia, perceptual-cognitive, posturo-locomotor, and vegetative disorders. We assessed the effectiveness of acute corticotherapy, and the functional role of acute inflammation observed after sudden unilateral vestibular loss. METHODS: We used the rodent model of unilateral vestibular neurectomy, mimicking the syndrome observed in patients with APV. We treated the animals during the acute phase of the vestibular syndrome, either with placebo or methylprednisolone, an anti-inflammatory corticosteroid. At the cellular level, impacts of methylprednisolone on endogenous plasticity mechanisms were assessed through analysis of cell proliferation and survival, glial reactions, neuron's membrane excitability, and stress marker. At the behavioral level, vestibular and posturo-locomotor functions' recovery were assessed with appropriate qualitative and quantitative evaluations. RESULTS: We observed that acute treatment with methylprednisolone significantly decreases glial reactions, cell proliferation and survival. In addition, stress and excitability markers were significantly impacted by the treatment. Besides, vestibular syndrome's intensity was enhanced, and vestibular compensation delayed under acute methylprednisolone treatment. CONCLUSIONS: We show here, for the first time, that acute anti-inflammatory treatment alters the expression of the adaptive plasticity mechanisms in the deafferented vestibular nuclei and generates enhanced and prolonged vestibular and postural deficits. These results strongly suggest a beneficial role for acute endogenous neuroinflammation in vestibular compensation. They open the way to a change in dogma for the treatment and therapeutic management of vestibular patients.

Caffeine consumption improves motor and cognitive performances during dual tasking in middle-aged women.

The aim of the present study was to explore the effect of caffeine consumption (CC) on cognitive motor interference while walking and maintaining balance in middle-aged women. Twenty middle-aged women (52 ± 2.0 years; height 158 ± 2.0 cm; body mass 77 ± 14.9 kg; body mass index ±3.4 kg/m2, mean ± SD) participated in this study. Participants completed measures of a single task (ST) cognitive, a ST motor and a dual task (DT) cognitive-motor tests before and after either caffeine (100 mg) or placebo ingestion. Results showed that before CC, both motor (P < 0.0005) and cognitive (P < 0.05) performances decreased in the DT condition compared to the ST one. After CC, no significant difference in the motor performances between ST and DT conditions was observed. In fact, both standing and walking DT performances were improved as indicated by a significant (P < 0.05) decrease in the dual task cost (DTC) of motor performances. In conclusion, middle-aged women showed difficulties to manage DT situations in which a cognitive and a motor task must be performed concurrently. Caffeine is an effective ergogenic aid to improve both cognitive and motor performances during DT conditions and could be an alternative to nullify the deteriorating effect of DT when maintaining balance and walking in middle-aged women. These enhancements could offer great potential for everyday functioning.

Effects of Bedtime Dosing With Suvorexant and Zolpidem on Balance and Psychomotor Performance in Healthy Elderly Participants During the Night and in the Morning.

PURPOSE/BACKGROUND: This study was designed as an early assessment of the safety of the orexin receptor antagonist suvorexant, but also included exploratory assessments of balance and psychomotor performance that are the focus of this report. METHODS/PROCEDURES: This was a double-blind, randomized, 3-period, crossover, phase 1 study. Balance and psychomotor performance were evaluated during the night in 12 healthy elderly participants after bedtime administration of suvorexant 30 mg (a supratherapeutic dose), the GABAergic agonist zolpidem 5 mg (the recommended dose in the elderly), or placebo. Balance (body sway measured by platform stability) and psychomotor performance (measured by choice reaction time) were assessed predose and at 1.5, 4, and 8 hours postdose in each period. Memory (measured by word recall) was assessed predose and at 4 hours postdose. FINDINGS/RESULTS: At 1.5 hours after nighttime administration of each drug (the approximate time of their anticipated maximal plasma concentrations), both zolpidem and suvorexant increased body sway versus placebo, with a greater increase for zolpidem than suvorexant. Suvorexant increased choice reaction time compared with placebo or zolpidem at 1.5 hours. There were no treatment differences on body sway or choice reaction time at 4 or 8 hours, or on word recall at 4 hours. IMPLICATIONS/CONCLUSIONS: These exploratory data suggest that a 30-mg dose of suvorexant (supratherapeutic) and a 5-mg dose of zolpidem (recommended dose in the elderly) impaired balance at 1.5 hours in healthy elderly people, with potentially less impairment for suvorexant relative to zolpidem, but no treatment differences on body sway or psychomotor performance at 4 and 8 hours. Because of their exploratory nature, these findings and their clinical relevance, if any, require confirmation in a prospective study.

α4ß2* Nicotinic Cholinergic Receptor Target Engagement in Parkinson Disease Gait-Balance Disorders.

OBJECTIVE: Attentional deficits following degeneration of brain cholinergic systems contribute to gait-balance deficits in Parkinson disease (PD). As a step toward assessing whether α4ß2* nicotinic acetylcholine receptor (nAChR) stimulation improves gait-balance function, we assessed target engagement of the α4ß2* nAChR partial agonist varenicline. METHODS: Nondemented PD participants with cholinergic deficits were identified with [18 F]fluoroethoxybenzovesamicol positron emission tomography (PET). α4ß2* nAChR occupancy after subacute oral varenicline treatment was measured with [18 F]flubatine PET. With a dose selected from the nAChR occupancy experiment, varenicline effects on gait, balance, and cognition were assessed in a double-masked placebo-controlled crossover study. Primary endpoints were normal pace gait speed and a measure of postural stability. RESULTS: Varenicline doses (0.25mg per day, 0.25mg twice daily [b.i.d.], 0.5mg b.i.d., and 1.0mg b.i.d.) produced 60 to 70% receptor occupancy. We selected 0.5mg orally b.i.d for the crossover study. Thirty-three participants completed the crossover study with excellent tolerability. Varenicline had no significant impact on the postural stability measure and caused slower normal pace gait speed. Varenicline narrowed the difference in normal pace gait speed between dual task and no dual task gait conditions, reduced dual task cost, and improved sustained attention test performance. We obtained identical conclusions in 28 participants with treatment compliance confirmed by plasma varenicline measurements. INTERPRETATION: Varenicline occupied α4ß2* nicotinic acetylcholine receptors, was tolerated well, enhanced attention, and altered gait performance. These results are consistent with target engagement. α4ß2* agonists may be worth further evaluation for mitigation of gait and balance disorders in PD. ANN NEUROL 2021;90:130-142.