Concern about falling is associated with segmental control when turning in older adults.

BACKGROUND: Healthy young adults typically exhibit a progressive 'top-down' reorientation of body segments (i.e., head, trunk, then pelvis) during turning. This behaviour is less evident in older adults at risk of falling, who often reduce angular displacement between body segments during turns. The potential functional and psychological contributors to this so-called 'en-bloc' turning strategy are not yet understood. RESEARCH QUESTION: Are there associations between concern about falling and variables representing en-bloc turning (i.e., increased coupling between body segments)? METHODS: Twenty-one older adults were assessed while turning during an adaptive walking task. We collected data from markers forming the head, trunk, and pelvis segments, while gait velocity throughout the turn was calculated from a sternum marker. We correlated several variables with concern about falling alone, as well as while controlling for functional balance ability. RESULTS: Correlation analyses revealed that concern about falling was related to en-bloc turning strategies and slower gait velocity throughout the turn, when analysed independently of functional balance. When controlling for balance ability, en-bloc turning strategies between the head and trunk, as well as the head and pelvis, remained significantly associated with concern about falling. SIGNIFICANCE: Findings offer an insight into the potential role that psychological characteristics may have in determining older adults' turning behaviour and associated risk of falling.

Conscious Movement Processing, Fall-Related Anxiety, and the Visuomotor Control of Locomotion in Older Adults.

OBJECTIVES: Older adults anxious about falling will often consciously process walking movements in an attempt to avoid falling. They also fixate their gaze on the present step rather than looking ahead to plan future actions. The present work examined whether conscious movement strategies result in such restricted visual planning. METHODS: A total of 18 community-dwelling older adults (agemean = 71.22; SD = 5.75) walked along a path and stepped into two raised targets. Repeated-measures analyses of variance were used to compare gaze behavior and movement kinematics when participants walked: (a) at baseline (ground level); (b) under conditions designed to induce fall-related anxiety (walkway elevated 0.6 m); and (c) in the absence of anxiety (ground level), but with explicit instructions to consciously process movements. RESULTS: Participants reported increased conscious movement processing when walking both on the elevated walkway (fall-related anxiety condition) and at ground level when instructed to consciously process gait. During both conditions, participants altered their gaze behavior, visually prioritizing the immediate walkway 1-2 steps ahead (areas needed for the on-line visual control of individual steps) at the expense of previewing distal areas of the walking path required to plan future steps. These alterations were accompanied by significantly slower gait and increased stance durations prior to target steps. CONCLUSIONS: Consciously processing movement (in the relative absence of anxiety) resulted in gaze behavior comparable to that observed during conditions of fall-related anxiety. As anxious participants also self-reported directing greater attention toward movement, this suggests that fall-related anxiety may disrupt the visual control of gait through increased conscious movement processing.

Re-evaluating the measurement and influence of conscious movement processing on gait performance in older adults: Development of the Gait-Specific Attentional Profile.

BACKGROUND: Recent decades have seen increased interest in how anxiety-and associated changes in conscious movement processing (CMP)-can influence the control of balance and gait, particularly in older adults. However, the most prevalent scale used to measure CMP during gait (the Movement-Specific Reinvestment Scale (MSRS)) is generic (i.e., non-gait-specific) and potentially lacks sensitivity in this context. METHODS: In a preliminary study, we first sought to evaluate if MSRS scores associated with the number of CMP-related thoughts self-reported by older adults while walking. The next aim was to develop and validate a new questionnaire (the Gait-Specific Attentional Profile, G-SAP) capable of measuring gait-specific CMP, in addition to other attentional processes purported to influence gait. This scale was validated using responses from 117 (exploratory) and 107 (confirmatory factor analysis) older adults, resulting in an 11-item scale with four sub-scales: CMP, anxiety, fall-related ruminations, and processing inefficiencies. Finally, in a separate cohort of 53 older adults, we evaluated associations between scores from both the G-SAP CMP subscale and the MSRS, and gait outcomes measured using a GAITRite walkway in addition to participants' fall-history. RESULTS: MSRS scores were not associated with self-reported thoughts categorised as representing CMP. In regression analyses that controlled for functional balance, unlike the MSRS, the G-SAP subscale of CMP significantly predicted several gait characteristics including velocity (p = .033), step length (p = .032), and double-limb support (p = .015). SIGNIFICANCE: The G-SAP provides gait-specific measures of four psychological factors implicated in mediating the control of balance and gait. In particular, unlike the MSRS, the G-SAP subscale of CMP appears sensitive to relevant attentional processes known to influence gait performance. We suggest that the G-SAP offers an opportunity for the research community to further develop understanding of psychological factors impacting gait performance across a range of applied clinical contexts.

Evidence of a Link Between Fall-Related Anxiety and High-Risk Patterns of Visual Search in Older Adults During Adaptive Locomotion.

BACKGROUND: Older adults deemed to be at a high risk of falling will often display visual search behaviors likely to impair movement planning when negotiating environmental hazards. It has been proposed that these behaviors may be underpinned by fall-related anxiety. Thus, the aim of this study was to explore the effects of fall-related anxiety on visual search and stepping behaviors during adaptive gait. METHODS: Forty-four community-dwelling older adults (mean age = 74.61; standard deviation = 6.83) walked along a path and stepped into two raised targets. All participants completed walks at ground level, whereas participants deemed to be at a low risk of falling (n = 24) also completed walks under conditions designed to induce fall-related anxiety (walkway elevated 0.6 m). Participants' movement kinematics and gaze behavior were measured. RESULTS: During ground trials, "high-risk" participants visually prioritized the immediate walkway areas 1-2 steps ahead, at the expense of previewing future stepping constraints. This reduced planning appeared to negatively affect safety, with greater stepping errors observed for future constraints. When completing walks on the elevated walkway, "low-risk" participants similarly prioritized immediate walkway areas, at the expense of planning future stepping actions. These behaviors were associated with greater attention directed toward consciously processing walking movements. CONCLUSIONS: These findings provide evidence of a link between heightened fall-related anxiety and "high-risk" visual search behaviors associated with greater stepping errors. This information enhances our understanding of why high-risk older adults are less able to safely navigate environmental constraints.

Exploring attentional focus of older adult fallers during heightened postural threat.

OBJECTIVES: Threats to balance, and subsequent increases in fall-related anxiety, can disrupt attentional processing during gait in older adults, leading to behavioral adaptations which may increase fall risk. However, limited research has investigated what changes in attention occur to contribute to these disruptions. The aim of this research was to describe changes in attention that occur during gait when older adults' balance is threatened, while exploring how previous fall history and trait movement reinvestment (conscious monitoring and control of movement) also influence attention. METHODS: Forty older adults reported where they focus their attention when walking during two scenarios: (1) when they are relaxed and there is little risk of falling, and; (2) when their balance is threatened and they are anxious of falling. RESULTS: During the high-threat condition, participants reported greater attention towards movement processes, threats to balance, worries/disturbing thoughts and self-regulatory strategies, with less attention directed towards task-irrelevant thoughts. However, fall history influenced attentional focus, with fallers directing greater attention towards worries/disturbing thoughts. Contrary to predictions, trait movement reinvestment was not associated with attention directed towards movement processes. DISCUSSION: As processing worries/disturbing thoughts will likely reduce attentional resources available for effective postural control, we highlight this as one potential area to target interventions aimed at reducing the likelihood of repeated falling.

Gazing into Thin Air: The Dual-Task Costs of Movement Planning and Execution during Adaptive Gait.

We examined the effect of increased cognitive load on visual search behavior and measures of gait performance during locomotion. Also, we investigated how personality traits, specifically the propensity to consciously control or monitor movements (trait movement 'reinvestment'), impacted the ability to maintain effective gaze under conditions of cognitive load. Healthy young adults traversed a novel adaptive walking path while performing a secondary serial subtraction task. Performance was assessed using correct responses to the cognitive task, gaze behavior, stepping accuracy, and time to complete the walking task. When walking while simultaneously carrying out the secondary serial subtraction task, participants visually fixated on task-irrelevant areas 'outside' the walking path more often and for longer durations of time, and fixated on task-relevant areas 'inside' the walkway for shorter durations. These changes were most pronounced in high-trait-reinvesters. We speculate that reinvestment-related processes placed an additional cognitive demand upon working memory. These increased task-irrelevant 'outside' fixations were accompanied by slower completion rates on the walking task and greater gross stepping errors. Findings suggest that attention is important for the maintenance of effective gaze behaviors, supporting previous claims that the maladaptive changes in visual search observed in high-risk older adults may be a consequence of inefficiencies in attentional processing. Identifying the underlying attentional processes that disrupt effective gaze behaviour during locomotion is an essential step in the development of rehabilitation, with this information allowing for the emergence of interventions that reduce the risk of falling.

Anxiety, anticipation and contextual information: A test of attentional control theory.

We tested the assumptions of Attentional Control Theory (ACT) by examining the impact of anxiety on anticipation using a dynamic, time-constrained task. Moreover, we examined the involvement of high- and low-level cognitive processes in anticipation and how their importance may interact with anxiety. Skilled and less-skilled tennis players anticipated the shots of opponents under low- and high-anxiety conditions. Participants viewed three types of video stimuli, each depicting different levels of contextual information. Performance effectiveness (response accuracy) and processing efficiency (response accuracy divided by corresponding mental effort) were measured. Skilled players recorded higher levels of response accuracy and processing efficiency compared to less-skilled counterparts. Processing efficiency significantly decreased under high- compared to low-anxiety conditions. No difference in response accuracy was observed. When reviewing directional errors, anxiety was most detrimental to performance in the condition conveying only contextual information, suggesting that anxiety may have a greater impact on high-level (top-down) cognitive processes, potentially due to a shift in attentional control. Our findings provide partial support for ACT; anxiety elicited greater decrements in processing efficiency than performance effectiveness, possibly due to predominance of the stimulus-driven attentional system.

Dynamic walking features and improved walking performance in multiple sclerosis patients treated with fampridine (4-aminopyridine).

BACKGROUND: Impaired walking capacity is a frequent confinement in Multiple Sclerosis (MS). Patients are affected by limitations in coordination, walking speed and the distance they may cover. Also abnormal dynamic walking patterns have been reported, involving continuous deceleration over time. Fampridine (4-aminopyridine), a potassium channel blocker, may improve walking in MS. The objective of the current study was to comprehensively examine dynamic walking characteristics and improved walking capacity in MS patients treated with fampridine. METHODS: A sample of N = 35 MS patients (EDSS median: 4) underwent an electronic walking examination prior to (Time 1), and during treatment with fampridine (Time 2). Patients walked back and forth a distance of 25 ft for a maximum period of 6 min (6-minute 25-foot-walk). Besides the total distance covered, average speed on the 25-foot distance and on turns was determined separately for each test minute, at Time 1 and Time 2. RESULTS: Prior to fampridine administration, 27/35 patients (77 %) were able to complete the entire 6 min of walking, while following the administration, 34/35 patients (97 %) managed to walk for 6 min. In this context, walking distance considerably increased and treatment was associated with faster walking and turning across all six test minutes (range of effect sizes: partial eta squared = .34-.72). Importantly, previously reported deceleration across test minutes was consistently observable at Time 1 and Time 2. DISCUSSION: Fampridine administration is associated with improved walking speed and endurance. Regardless of a treatment effect of fampridine, the previously identified, abnormal dynamic walking feature, i.e. the linear decline in walking speed, may represent a robust feature. CONCLUSIONS: The dynamic walking feature might hence be considered as a candidate for a new outcome measure in clinical studies involving interventions other than symptomatic treatment, such as immune-modulating medication. TRIAL REGISTRATION: DRKS00009228 (German Clinical Trials Register). Date obtained: 25.08.2015.