Dissociated cerebellar contributions to feedforward gait adaptation.

The cerebellum is important for motor adaptation. Lesions to the vestibulo-cerebellum selectively cause gait ataxia. Here we investigate how such damage affects locomotor adaptation when performing the 'broken escalator' paradigm. Following an auditory cue, participants were required to step from the fixed surface onto a moving platform (akin to an airport travellator). The experiment included three conditions: 10 stationary (BEFORE), 15 moving (MOVING) and 10 stationary (AFTER) trials. We assessed both behavioural (gait approach velocity and trunk sway after stepping onto the moving platform) and neuromuscular outcomes (lower leg muscle activity, EMG). Unlike controls, cerebellar patients showed reduced after-effects (AFTER trials) with respect to gait approach velocity and leg EMG activity. However, patients with cerebellar damage maintain the ability to learn the trunk movement required to maximise stability after stepping onto the moving platform (i.e., reactive postural behaviours). Importantly, our findings reveal that these patients could even initiate these behaviours in a feedforward manner, leading to an after-effect. These findings reveal that the cerebellum is crucial for feedforward locomotor control, but that adaptive locomotor behaviours learned via feedback (i.e., reactive) mechanisms may be preserved following cerebellum damage.

The influence of false interoceptive feedback on emotional state and balance responses to height-induced postural threat.

Postural threat elicits a robust emotional response (e.g., fear and anxiety about falling), with concomitant modifications in balance. Recent theoretical accounts propose that emotional responses to postural threats are manifested, in part, from the conscious monitoring and appraisal of bodily signals ('interoception'). Here, we empirically probe the role of interoception in shaping emotional responses to a postural threat by experimentally manipulating interoceptive cardiac feedback. Sixty young adults completed a single 60-s trial under the following conditions: Ground (no threat) without heart rate (HR) feedback, followed by Threat (standing on the edge of a raised surface), during which participants received either false heart rate feedback (either slow [n = 20] or fast [n = 20] HR feedback) or no feedback (n = 20). Participants provided with false fast HR feedback during postural threat felt more fearful, reported feeling less stable, and rated the task more difficult than participants who did not receive HR feedback, or those who received false slow HR feedback (Cohen's d effect size = 0.79 - 1.78). However, behavioural responses did not significantly differ across the three groups. When compared to the no HR feedback group, false slow HR feedback did not significantly affect emotional or behavioural responses to the postural threat. These observations provide the first experimental evidence for emerging theoretical accounts describing the role of interoception in the generation of emotional responses to postural threats.

The influence of postural threat-induced anxiety on locomotor learning and updating.

The ability to adapt our locomotion in a feedforward (i.e., "predictive") manner is crucial for safe and efficient walking behavior. Equally important is the ability to quickly deadapt and update behavior that is no longer appropriate for the given context. It has been suggested that anxiety induced via postural threat may play a fundamental role in disrupting such deadaptation. We tested this hypothesis, using the "broken escalator" phenomenon: Fifty-six healthy young adults walked onto a stationary walkway ("BEFORE" condition, 5 trials), then onto a moving walkway akin to an airport travelator ("MOVING" condition, 10 trials), and then again onto the stationary walkway ("AFTER" condition, 5 trials). Participants completed all trials while wearing a virtual reality headset, which was used to induce postural threat-related anxiety (raised clifflike drop at the end of the walkway) during different phases of the paradigm. We found that performing the locomotor adaptation phase in a state of increased threat disrupted subsequent deadaptation during AFTER trials: These participants displayed anticipatory muscular activity as if expecting the platform to move and exhibited inappropriate anticipatory forward trunk movement that persisted during multiple AFTER trials. In contrast, postural threat induced during AFTER trials did not affect behavioral or neurophysiological outcomes. These findings highlight that actions learned in the presence of postural threat-induced anxiety are strengthened, leading to difficulties in deadapting these behaviors when no longer appropriate. Given the associations between anxiety and persistent maladaptive gait behaviors (e.g., "overly cautious" gait, functional gait disorders), the findings have implications for the understanding of such conditions.NEW & NOTEWORTHY Safe and efficient locomotion frequently requires movements to be adapted in a feedforward (i.e., "predictive") manner. These adaptations are not always correct, and thus inappropriate behavior must be quickly updated. Here we showed that increased threat disrupts this process. We found that locomotor actions learned in the presence of postural threat-induced anxiety are strengthened, subsequently impairing one's ability to update (or "deadapt") these actions when they are no longer appropriate for the current context.

Factors associated with concerns about falling and activity restriction in older adults after hip fracture: a mixed-methods systematic review.

PURPOSE: To investigate factors contributing to concerns about falling and activity restriction in the community among older adults who had a hip fracture. METHODS: A mixed method systematic review with a convergent segregated approach. We searched Medline, Embase, PsycInfo, PEDRo, CINAHL and the Cochrane library. Results were synthesised narratively considering physical, psychological, environmental, care, and social factors and presented in tables. Critical appraisal was completed in duplicate. RESULTS: We included 19 studies (9 qualitative, 9 observational, 1 mixed methods) representing 1480 individuals and 23 factors related to concerns about falling and activity restriction. Physical factors included falls history, comorbidities, balance, strength, mobility and functionality. Psychological factors included anxiety and neuroticism scores, perceived confidence in/control over rehabilitation and abilities, and negative/positive affect about the orthopaedic trauma, pre-fracture abilities and future needs. Environmental factors included accessibility in the home, outdoors and with transport. Social and care factors related to the presence or absence of formal and informal networks, which reduced concerns and promoted activity by providing feedback, advice, encouragement, and practical support. CONCLUSION: These findings highlight that to improve concerns about falling and activity restriction after hip fracture, it is important to: improve physical and functional abilities; boost self-confidence; promote positive affect; involve relatives and carers; increase access to clinicians, and; enhance accessibility of the home, outdoors and transport. Most factors were reported on by a small number of studies of varying quality and require replication in future research.

Exploring the role of attention towards balance in chronic dizziness: Development of the Balance Vigilance Questionnaire.

BACKGROUND AND PURPOSE: Vigilance towards balance has been proposed to underpin various chronic dizziness disorders, including persistent postural-perceptual dizziness (PPPD). The objective of this study was to develop (through patient input) a validated balance-specific measure of vigilance that comprehensively assesses the varied ways in which this construct may manifest. METHODS: We developed the Balance Vigilance Questionnaire (Balance-VQ) through patient and clinician feedback, designed to assess vigilance towards balance. We then validated the questionnaire in 497 participants consisting of patients diagnosed with chronic dizziness disorders (including 97 individuals diagnosed with PPPD) and healthy controls. RESULTS: The final six-item Balance-VQ was shown to be a valid and reliable way to assess vigilance towards balance. Scores were significantly higher in individuals diagnosed with PPPD compared to controls. Although scores were also higher in the PPPD group compared to individuals with diagnosed vestibular disorders other than PPPD, Balance-VQ scores did not discriminate between the two groups when confounding factors (including dizziness severity) were controlled for. Scores did, however, independently discriminate between the PPPD group and individuals who experience dizziness in daily life, but who have not been diagnosed with a neuro-otological disorder. CONCLUSIONS: Our findings confirm that the Balance-VQ is a valid and reliable instrument for assessing vigilance towards balance. As symptom vigilance has been identified as a key risk factor for developing chronic dizziness following acute vestibular symptoms or balance disruption, we recommend using the Balance-VQ as a screening tool in people presenting with such symptoms.

Short-latency reaction time and accuracy are impaired in patients with cirrhosis: An international multicenter retrospective study.

AIM: The inability to quickly react to an external event can lead to an increased risk for accidents (e.g., falls, car crashes) in patients with cirrhosis. The aim of this study was to determine whether a novel clinically feasible measure of simple reaction time (SRT) and reaction accuracy (RA)-a go/no-go task occurring within 400 ms-could differentiate patients with cirrhosis from controls. METHODS: This retrospective study included 160 patients with cirrhosis and 160 controls assessed between January 2010 and October 2022. SRT and RA were evaluated using a ruler drop paradigm and compared using propensity score matching. Factors distinguishing patients with cirrhosis from controls were assessed using logistic regression and receiver operating characteristics curve (ROC) analyses. RESULTS: Propensity score matching identified 112 participants in each group with comparable baseline characteristics. As compared with controls, patients with cirrhosis exhibited significantly prolonged SRT (200 vs. 174 ms; P < 0.001) and diminished total RA (63% vs. 73%; P < 0.001). After adjustment for confounding factors, SRT and RA independently identified patients with cirrhosis. ROC analyses showed that SRT more effectively identified patients with cirrhosis than did the number-connection test/trail-making test-B (area under the curve, 0.87 vs. 0.60; P < 0.001). CONCLUSIONS: Patients with cirrhosis demonstrated impairments in short-latency cognitive function. Given that SRT and RA are associated with balance, falls, and response to perturbation, these parameters may present a task-specific method to identify patients with cirrhosis at high risk of falls and motor vehicle crashes. Geriatr Gerontol Int 2024; 24: 25-31.

We should be screening for benign paroxysmal positional vertigo (BPPV) in all older adults at risk of falling: a commentary on the World Falls Guidelines.

Benign paroxysmal positional vertigo (BPPV) is amongst the commonest causes of dizziness and falls in older adults. Diagnosing and treating BPPV can reduce falls, and thereby reduce fall-related morbidity and mortality. Recent World Falls Guidelines recommend formal assessment for BPPV in older adults at risk of falling, but only if they report vertigo. However, this recommendation ignores the data that (i) many older adults with BPPV experience dizziness as vague unsteadiness (rather than vertigo), and (ii) others may experience no symptoms of dizziness at all. BPPV without vertigo is due to an impaired vestibular perception of self-motion, termed 'vestibular agnosia'. Vestibular agnosia is found in ageing, neurodegeneration and traumatic brain injury, and results in dramatically increased missed BPPV diagnoses. Patients with BPPV without vertigo are typically the most vulnerable for negative outcomes associated with this disorder. We thus recommend simplifying the World Falls Guidelines: all older adults (>60 years) with objective or subjective balance problems, irrespective of symptomatic complaint, should have positional testing to examine for BPPV.

Vestibular loss disrupts visual reactivity in the alpha EEG rhythm.

The alpha rhythm is a dominant electroencephalographic oscillation relevant to sensory-motor and cognitive function. Alpha oscillations are reactive, being for example enhanced by eye closure, and suppressed following eye opening. The determinants of inter-individual variability in reactivity in the alpha rhythm (e.g. changes with amplitude following eye closure) are not fully understood despite the physiological and clinical applicability of this phenomenon, as indicated by the fact that ageing and neurodegeneration reduce reactivity. Strong interactions between visual and vestibular systems raise the theoretical possibility that the vestibular system plays a role in alpha reactivity. To test this hypothesis, we applied electroencephalography in sitting and standing postures in 15 participants with reduced vestibular function (bilateral vestibulopathy, median age = 70 years, interquartile range = 51-77 years) and 15 age-matched controls. We found participants with reduced vestibular function showed less enhancement of alpha electroencephalography power on eye closure in frontoparietal areas, compared to controls. In participants with reduced vestibular function, video head impulse test gain - as a measure of residual vestibulo-ocular reflex function - correlated with reactivity in alpha power across most of the head. Greater reliance on visual input for spatial orientation ('visual dependence', measured with the rod-and-disc test) correlated with less alpha enhancement on eye closure only in participants with reduced vestibular function, and this was partially moderated by video head impulse test gain. Our results demonstrate for the first time that vestibular function influences alpha reactivity. The results are partly explained by the lack of ascending peripheral vestibular input but also by central reorganisation of processing relevant to visuo-vestibular judgements.

The perceived control model of falling: developing a unified framework to understand and assess maladaptive fear of falling.

BACKGROUND: fear of falling is common in older adults and can have a profound influence on a variety of behaviours that increase fall risk. However, fear of falling can also have potentially positive outcomes for certain individuals. Without progressing our understanding of mechanisms underlying these contrasting outcomes, it is difficult to clinically manage fear of falling. METHODS: this paper first summarises recent findings on the topic of fear of falling, balance and fall risk-including work highlighting the protective effects of fear. Specific focus is placed on describing how fear of falling influences perceptual, cognitive and motor process in ways that might either increase or reduce fall risk. Finally, it reports the development and validation of a new clinical tool that can be used to assess the maladaptive components of fear of falling. RESULTS: we present a new conceptual framework-the Perceived Control Model of Falling-that describes specific mechanisms through which fear of falling can influence fall risk. The key conceptual advance is the identification of perceived control over situations that threaten one's balance as the crucial factor mediating the relationship between fear and increased fall risk. The new 4-item scale that we develop-the Updated Perceived Control over Falling Scale (UP-COF)-is a valid and reliable tool to clinically assess perceived control. CONCLUSION: this new conceptualisation and tool (UP-COF) allows clinicians to identify individuals for whom fear of falling is likely to increase fall risk, and target specific underlying maladaptive processes such as low perceived control.

Validating the Breathing Vigilance Questionnaire for use in dysfunctional breathing.

BACKGROUND: Dysfunctional breathing is common among people with and without primary respiratory pathology. While anxiety can contribute to dysfunctional breathing, the underpinning mechanism is unclear. One explanation is that anxiety induces conscious, vigilant monitoring of breathing, disrupting "automatic" breathing mechanics. We validated a new tool that quantifies such breathing-related "vigilance": the Breathing Vigilance Questionnaire (Breathe-VQ). METHODS: 323 healthy adults (mean (range) age 27.3 (18-71) years; 161 males) were analysed. We developed an initial Breathe-VQ (11 items, 1-5 Likert scale) based on the Pain Vigilance and Awareness Scale, using feedback from the target population and clinicians. At baseline, participants completed the Breathe-VQ, Nijmegen Questionnaire (NQ), State-Trait Anxiety Inventory form 2 and Movement-Specific Reinvestment Scale (assessing general conscious processing). 83 people repeated the Breathe-VQ 3 weeks later. RESULTS: Five items were removed based on item-level analysis. The resulting six-item Breathe-VQ questionnaire (score range 6-30) has excellent internal (α=0.892) and test-retest reliability (intraclass correlation 0.810), a minimal detectable change of 6.5 and no floor/ceiling effects. Validity was evidenced by significant positive correlations with trait anxiety and conscious processing scores (r=0.35-0.46). Participants at high risk of having dysfunctional breathing (NQ >23; n=76) had significantly higher Breathe-VQ score (mean±sd 19.1±5.0) than low-risk peers (n=225; mean±sd 13.8±5.4; p<0.001). In this "high risk of dysfunctional breathing" group, Breathe-VQ and NQ scores were significantly associated (p=0.005), even when controlling for risk factors (e.g. trait anxiety). CONCLUSIONS: The Breathe-VQ is a valid and reliable tool to measure breathing vigilance. High breathing vigilance may contribute to dysfunctional breathing and could represent a therapeutic target. Further research is warranted to test Breathe-VQ's prognostic value and assess intervention effects.

Why should clinical practitioners ask about their patients' concerns about falling?

Concerns (or 'fears') about falling (CaF) are common in older adults. As part of the 'World Falls Guidelines Working Group on Concerns about Falling', we recommended that clinicians working in falls prevention services should regularly assess CaF. Here, we expand upon these recommendations and argue that CaF can be both 'adaptive' and 'maladaptive' with respect to falls risk. On the one hand, high CaF can lead to overly cautious or hypervigilant behaviours that increase the risk of falling, and may also cause undue activity restriction ('maladaptive CaF'). But concerns can also encourage individuals to make appropriate modifications to their behaviour to maximise safety ('adaptive CaF'). We discuss this paradox and argue that high CaF-irrespective of whether 'adaptive' or 'maladaptive'-should be considered an indication that 'something is not right', and that is represents an opportunity for clinical engagement. We also highlight how CaF can be maladaptive in terms of inappropriately high confidence about one's balance. We present different routes for clinical intervention based on the types of concerns disclosed.

Frailty, falls and poor functional mobility predict new onset of activity restriction due to concerns about falling in older adults: a prospective 12-month cohort study.

PURPOSE: Concerns about falling are common in older adults and often cause activity restriction. This can lead to physical deconditioning, falls and social isolation. However, not every concerned older adult will restrict their activities. This 12-month longitudinal study investigated the physical and psychosocial factors that predict the new onset of activity restriction due to concerns about falling in older people. METHODS: Participants were 543 older adults (Mage = 80.3 ± 4.4 years, range: 75-98) who did not report activity restriction due to concerns about falling at Timepoint-1 (negative response to the following question: "Do concerns about falling stop you going out-and-about?"). Participants completed a battery of physical and psychological assessments at Timepoint-1. Using binary logistic regression, we then assessed which of these variables predicted whether participants reported having started restricting their activity due to concerns about falling at the 12-month follow-up (Timepoint 2). RESULTS: 10.1% of the sample started to restrict activity due to concerns about falling at Timepoint 2. Three key predictors significantly predicted activity restriction group status at 12-month follow-up: greater frailty at Timepoint-1 (Fried Frailty Index; OR = 1.58, 95% CI 1.09-2.30), experiencing a fall between Timepoint-1 and 2 (OR = 2.22, 95% CI 1.13-4.38) and poorer functional mobility at Timepoint-1 (Timed up and Go; OR = 1.08, 95% CI 1.01-1.15). CONCLUSIONS: Frailty, experiencing a fall and poorer functional mobility all predicted the onset of activity restriction due to concerns about falling. Clinicians working in balance and falls-prevention services should regularly screen for frailty, and patients referred to frailty services should likewise receive tailored treatment to help prevent the development of activity restriction due to concerns about falling.

The Effects of Conscious Movement Processing on the Neuromuscular Control of Posture.

Maintaining balance is thought to primarily occur sub-consciously. Occasionally, however, individuals will direct conscious attention towards balance, e.g., in response to a threat to balance. Such conscious movement processing (CMP) increases the reliance on attentional resources and may disrupt balance performance. However, the underlying changes in neuromuscular control remain poorly understood. We investigated the effects of CMP (manipulated using verbal instructions) on neural control of posture in twenty-five adults (11 females, mean age = 23.9, range = 18-33). Participants performed 90-s, bipedal stance balance trials in high- and low-CMP conditions, during both stable (solid surface) and unstable (foam) task conditions. Postural sway amplitude, frequency and complexity were used to assess postural control. Surface EMG was recorded bilaterally from lower leg muscles (Soleus, Tibialis Anterior, Gastrocnemius Medialis, Peroneus Longus) and intermuscular coherence (IMC) was assessed for 12 muscle pairs across four frequency bands. We observed significantly increased sway amplitude, and decreased sway frequency and complexity in the high- compared to the low-CMP conditions. All sway variables increased in the unstable compared to the stable conditions. We observed reduced beta band IMC between several muscle pairs during high- compared to low-CMP, but these findings did not remain significant after controlling for multiple comparisons. Finally, IMC significantly increased in the unstable conditions for most muscle combinations and frequency bands. In all, results tentatively suggest that CMP-induced changes in sway outcomes may be facilitated by reduced beta-band IMC, but these findings need to be replicated before they can be interpreted more conclusively.

Optimal Training for Movement Acquisition and Transfer: Does "Externally Focused" Visual Biofeedback Promote Implicit Motor Learning?

CONTEXT: Visual biofeedback has been shown to facilitate injury-resistant movement acquisition in adolescent athletes. Visual biofeedback is typically thought to foster implicit learning by stimulating athletes to focus attention externally (on movement outcome). However, biofeedback may also induce explicit learning if the athlete uses the visual information to consciously guide movement execution (via an internal focus). OBJECTIVE: To determine the degree to which athletes reported statements indicating implicit or explicit motor learning after engaging in a visual biofeedback intervention. DESIGN: Prospective cohort study. SETTING: Three-dimensional motion-analysis laboratory. PATIENTS OR OTHER PARTICIPANTS: Twenty-five adolescent female soccer athletes (age = 15.0 ± 1.5 years, height = 165.7 ± 5.9 cm, mass = 59.4 ± 10.6 kg). INTERVENTIONS: Standard 6-week neuromuscular training intervention (three 90-minute sessions/wk), with added visual biofeedback sessions (2 sessions/wk). For the biofeedback training, participants performed squatting and jumping movements while interacting with a visual rectangular stimulus that mapped key parameters associated with injury risk. After the last biofeedback session in each week, participants answered open-ended questions to probe learning strategies. MAIN OUTCOME MEASURE(S): Responses to the open-ended questions were categorized as externally focused (ie, on movement outcome, suggestive of implicit learning), internally focused (ie, on movement itself, suggestive of explicit learning), mixed focus, or other. RESULTS: A total of 171 open-ended responses were collected. Most of the responses that could be categorized (39.2%) were externally focused (41.8%), followed by mixed (38.8%) and internally focused (19.4%). The frequency of externally focused statements increased from week 1 (18%) to week 6 (50%). CONCLUSIONS: Although most statements were externally focused (suggesting implicit learning), the relatively large proportion of internal- and mixed-focus statements suggested that many athletes also engaged in explicit motor learning, especially in early practice sessions. Therefore, biofeedback may affect motor learning through a mixture of implicit and explicit learning.

Talking really does matter: Lay perspectives from older people on talking about suicide in later life.

Background: The cumulative body of research on suicidality in later life describes its unique and complex features in older people when compared with that in other population groups. Yet significant gaps exist in how research informs the further development of suitable interventions. The perspectives of older people are also limited in research findings. Aims: Therefore, this exploratory study aimed to (1) identify potential barriers and enablers in discussing suicidal thoughts and their expression in later life from the perspectives of lay older people and (2) explore where opportunities might occur in approach, place, relationships, and language with older people to discuss suicidal thoughts and their expression. Method: We conducted in-depth qualitative individual interviews with 15 people aged 70-89 years. This method helped explore older peoples' own lay perspectives on suicidal thoughts in later life and how these are expressed, and their understanding of where and how people might seek support. Results: A total of three themes were generated from the dataset: (1) intergenerational and socio-cultural differences in suicide expression, (2) the normalization of suicidal thoughts in later life, and (3) the importance and difficulties of everyday discussion and opportunities to express suicidal thoughts. Conclusion: Suicidal thoughts and their expression appear commonly and are normalized in later life yet remain taboo and hidden. The participants revealed how such thoughts and behaviors are typically expressed through colloquial or "off-hand" remarks and comments and the importance of authentic listening. The findings highlight the importance of more informal discussions around these topics and how care professionals, practitioners, and providers might frame opportunities for dialogue with people who may want to access support. Further engagement with community-informed participatory research methods in which older people provide their own perspectives and experiences is important in addressing these gaps. There is a need for co-designing in developing screening, assessment, and signposting outside of clinical settings that can be used in everyday caring relationships with people in later life.

The relationship between clinical measures of cognitive function and grip strength in healthy older adults.

BACKGROUND: Handgrip strength is considered a surrogate for musculoskeletal strength, however there is emerging evidence of an association with cognition. The specific neurocognitive attribute which best associates with grip strength is unknown. METHODS: We performed a secondary analysis on baseline data in 49 healthy older adults. Grip strength was corrected for body mass index. Control independent variables included age, Montreal Cognitive Assessment, and Trails B. Experimental variables included a clinical measure of simple reaction time, and clinical and computerized go/no-go tasks. The clinical Go/No-Go measure was determined with ReacStick, a rod-shaped device which - when released by the examiner - requires the participant to decide within 390 ms whether to catch the device or let it fall to the ground. RESULTS: Bivariate analysis demonstrated that age and all cognitive measures other than the computer go/no-go response accuracy related to grip strength. Multivariate analyses showed that following inclusion of the control variables, only ReacStick measures (reaction accuracy/simple reaction time) significantly predicted grip strength, explaining an additional 15.90% variance (p = 0.026). In contrast, computerized Go/No-Go accuracy (p = 0.391), response time variability (p = 0.463), and the control variables (p value range = 0.566-0.942) did not predict grip strength. CONCLUSION: A short latency (< 390 ms) visuomotor Go/No-Go task independently predicted over 15% of grip strength variance, whereas a slower screen-based Go/No-Go task did not. These findings support the notion that declining grip strength likely reflects sub-clinical brain changes as well as musculoskeletal dysfunction, possibly explaining the potent relationships between grip strength, disability, chronic disease, and mortality.

A comparison of placebo and nocebo effects on objective and subjective postural stability: a double-edged sword?

Background: Positive expectations (i.e., placebo effect) can improve postural control during quiet standing. This raises an important question: if postural control is susceptible to positive expectations, is it possible to elicit the opposite, a decline in postural stability, simply by suggesting a performance impairment (i.e., nocebo) will take place? Yet no studies have examined the nocebo effect on balance performance. To better understand both phenomena, comparative studies, which include both placebo and nocebo conditions, are needed. Method: Forty-two healthy adults were initially assessed for objective (center of pressure movement) and subjective (perceived) postural stability and performance expectations. Participants were then randomly assigned in equal numbers to a placebo (positive expectation), nocebo (negative expectation) or control (no suggestion) group. Participants in the placebo/nocebo groups were deceptively administered an inert capsule described as a potent supplement which would either positively or negatively influence their balance performance. Objective and subjective postural stability, and performance expectations were reassessed 20 min later. Results: The nocebo procedure evoked an increase in COP sway movements and reduced perceived stability compared to a control group. The placebo group presented with reductions COP sway movements and increased perceived stability following expectation manipulation. Compared to the control group, the placebo group showed a significantly higher performance expectation whilst the nocebo group showed a significantly lower performance expectation. Regression analyses also revealed that performance expectations following the placebo/nocebo procedure significantly predicted perceptions of postural instability (i.e., perceived performance), accounting for around 50% of the variance. These results remained even when controlling for actual performance (i.e., objective postural stability). Conclusion: Our findings indicate that positive and negative performance expectations evoked by instructional manipulation can profoundly influence both objective and subjective postural stability. Postural control-and perceptions regarding such-are clearly susceptible to expectation manipulation, which could have important practical implications and repercussions on testing, training interventions and rehabilitation programs. Positive and negative expectancies are a double-edged sword for postural control.

Protective or harmful? A qualitative exploration of older people's perceptions of worries about falling.

BACKGROUND: worries about falling are common in older people. It has been suggested that these worries can reduce balance safety by acting as a distracting dual-task. However, it is also possible that worries may serve a protective purpose. The present work adopted a qualitative approach to conduct an in-depth exploration of older people's experiences of worries about falling. METHODS: semi-structured interviews were conducted with 17 community-dwelling older people (mean age = 79 years; males = 5/17) who reported experiencing worries about falling. Reflexive thematic analysis was used to analyse the data. RESULTS: experiencing a fall-or otherwise recognising one's balance limitations-brought the physical realities of participants' ageing bodies to the forefront of their awareness. This led to the recognition of their susceptibility for an injurious fall, which triggered worries about falling in situations that threatened their balance. When preventing the subject of their worries (i.e. an injurious fall) was perceived to be within the individual's locus of control, worries led to protective adaptations to behaviour. In contrast, when the subject of their worries was perceived to be outside their control, worries triggered feelings of panic-leading to unhelpful changes in behaviour. CONCLUSION: these findings provide novel insight into the development and consequences of worries about falling in older people. They highlight the importance of considering an individual's perception of control before deciding to clinically intervene to reduce worries about falling.

Weighting for the Beat: Using a Dance Cue to Facilitate Turning in People with Parkinson's Disease and Freezing of Gait.

Freezing of gait (FOG) can severely compromise daily functioning in people with Parkinson's disease. Inability to initiate a step from FOG is likely underpinned, at least in part, by a deficient preparatory weight-shift. Conscious attempts to weight-shift in preparation to step can improve success of initiating forward steps following FOG. However, FOG often occurs during turning, where weight-shifting is more complex and risk of falling is higher. We explored the effectiveness of a dance-based ('cha-cha') weight-shifting strategy to re-initiate stepping following FOG during turning. Results suggest that this simple movement strategy can enhance turning steps following FOG, without compromising safety.