Impacts of dance on cognition, psychological symptoms and quality of life in Parkinson's disease.

BACKGROUND: While dance may improve motor features in Parkinson's disease (PD), it is not yet clear if the benefits extend to non-motor features. OBJECTIVE: To determine whether dance classes based on Dance for PD®, improve cognition, psychological symptoms and Quality of Life (QoL) in PD. METHODS: Participants were allocated to a Dance Group (DG; n = 17) or Control Group (CG: n = 16). Participants had early-stage PD (Hoehn & Yahr: DG = 1.6±0.7, CG = 1.5±0.8) with no cognitive impairment (Addenbrooke's score: DG = 93.2±3.6, CG = 92.6±4.3). The DG undertook a one-hour class, twice weekly for 12 weeks, while the CG had treatment as usual. Both groups were assessed for disease severity (MDS-UPDRS), cognition (NIH Toolbox® cognition battery, Trail Making Test), psychological symptoms (Hospital Anxiety and Depression Scale, MDS-UPDRS-I) and QoL (PDQ-39, MDS-UPDRS-II). RESULTS: Group comparison of pre-post change scores showed that selected cognitive skills (executive function and episodic memory), psychological symptoms (anxiety and depression) as well as QoL (PDQ-39 summary index) were significantly improved by the intervention (DG > CG, p's < 0.05, Cohen's d > 0.8). DISCUSSIONS AND CONCLUSION: Dance classes had a clear benefit on psychological symptoms, QoL and a limited cognitive benefit. Follow-up assessment is required to confirm the durability of these effects.

The impact of staffing model in a 6-day rehabilitation physiotherapy service.

BACKGROUND AND PURPOSE: The impact of staffing model providing weekend physiotherapy rehabilitation has not been evaluated. This study aims to determine the impact of staffing a weekend rehabilitation service with physiotherapists currently working in rehabilitation compared to acute hospital physiotherapists, on length of stay (LOS), functional independence and gait and balance, and to determine the impact on neurological, orthopaedic, and reconditioning diagnostic groups. METHODS: A prospective cohort study with historical control was completed in a private, metropolitan Australian rehabilitation unit. All participants admitted to the rehabilitation unit over two, 20-week periods in 2011 and 2012 were included. Weekend physiotherapy was provided by physiotherapists working in rehabilitation in 2012 (intervention) and physiotherapists working in the acute wards in 2011 (control). Outcomes included LOS, Functional Independence Measure (FIM), and gait and balance measures. RESULTS: Overall, there were 504 participants; 234 in 2012 and 270 in 2011. No difference was found in LOS between staffing models (mean difference-1.5 days, 95%CI -4.4 to 1.3). Greater FIM change (mean difference 3.5, 95%CI 0.3 to 6.7) and efficiency (FIM change/LOS: mean difference 0.3, 95%CI 0.1 to 0.5) were found with rehabilitation compared to acute staffing. There was no between-group difference in gait or balance performance. When diagnostic groups were compared, no difference in LOS was found between staffing models. Participants with an orthopaedic diagnosis had a significantly greater FIM change (mean difference 3.8, 95%CI 0.4 to 7.1), whereas FIM efficiency was improved in neurological (mean difference 0.4, 95%CI 0.1 to 0.7) and orthopaedic populations (mean difference 0.3, 95%CI 0.03 to 0.5) with rehabilitation staffing. DISCUSSION: Staffing a weekend rehabilitation service with physiotherapists currently working in rehabilitation influences functional independence. Different diagnostic groups appear to respond differently.

Prion-like properties of disease-relevant proteins in amyotrophic lateral sclerosis.

The hallmark of age-related neurodegenerative diseases is the appearance of cellular protein deposits and spreading of this pathology throughout the central nervous system. Growing evidence has shown the involvement and critical role of proteins with prion-like properties in the formation of these characteristic cellular aggregates. Prion-like domains of such proteins with their proposed function in the organization of membraneless organelles are prone for misfolding and promoting further aggregation. Spreading of these toxic aggregates between cells and across tissues can explain the progression of clinical phenotypes and pathology in a stereotypical manner, characteristic for almost every neurodegenerative disease. Here, we want to review the current evidence for the role of prion-like mechanisms in classical neurodegenerative diseases and ALS in particular. We will also discuss an intriguingly central role of the protein TDP-43 in the majority of cases of this devastating disease.

Focal humero-ulnar impingement following subtotal coronoid ostectomy in six dogs with fragmented medial coronoid process.

OBJECTIVE: To report acute eburnation of joint cartilage at the humeral trochlea following subtotal coronoid ostectomy (SCO) in a clinical case series of six elbows. MATERIAL AND METHODS: Six dogs (median BW 27.1 kg; median age 7.5 months) with fragmented medial coronoid process (FCP) and varying degree of radio-ulnar incongruence (RUI) (mean 2 mm) were treated with SCO using an arthroscopic burr. Second look arthroscopy 4-12 weeks later was performed either because of recurrent or persistent lameness in three dogs. In the others, second-look arthroscopy was scheduled prospectively because of RUI, which was thought to be a risk factor for the observed humero-ulnar impingement. RESULTS: All six elbows had a 1-2 mm wide line of focal full-thickness cartilage loss along the edge of the SCO, while the opposing trochlea had diffuse cartilage damage of Outerbridge grade III-IV, indicating focal humero-ulnar impingement. None of the elbows showed repeated FCP. CONCLUSION: In some cases SCO might lead to focal humero-ulnar impingement along the osteotomy line. CLINICAL SIGNIFICANCE: Whether this relays to variations in respect the amount of resected bone (too much vs. too less) or concomitant joint pathologies like RUI or joint instability remains unknown and warrants further studies.

Microbial sequencing analyses suggest the presence of a fecal veneer on indoor climbing wall holds.

Artificial climbing walls represent a unique indoor environment in which humans interact closely with a variety of surface types. Climbing wall holds may mediate transmission of organisms between individuals, and yet there are no studies that identify microorganisms present on these surfaces. In the current study, the microorganisms found on climbing wall holds were characterized by analysis of amplified SSU rRNA gene sequences. In contrast to many other studies of built environments, the majority of microorganisms on holds were most closely related to microbes annotated as being recovered from environmental sources, such as soil, with human skin also representing an important source. Regional patterns were evident as rRNA gene sequences from the marine cyanobacterium Prochlorococcus were abundant in gyms found within 16 km of the ocean. Enterobacteriaceae were present on 100 % of holds surveyed, and the members detected are commonly associated with fecal matter.

New insights into neck-pain-related postural control using measures of signal frequency and complexity in older adults.

There is evidence to implicate the role of the cervical spine in influencing postural control, however the underlying mechanisms are unknown. The aim of this study was to explore standing postural control mechanisms in older adults with neck pain (NP) using measures of signal frequency (wavelet analysis) and complexity (entropy). This cross-sectional study compared balance performance of twenty older adults with (age=70.3±4.0 years) and without (age=71.4±5.1 years) NP when standing on a force platform with eyes open and closed. Anterior-posterior centre-of-pressure data were processed using wavelet analysis and sample entropy. Performance-based balance was assessed using the Timed Up-and-Go (TUG) and Dynamic Gait Index (DGI). The NP group demonstrated poorer functional performance (TUG and DGI, p<0.01) than the healthy controls. Wavelet analysis revealed that standing postural sway in the NP group was positively skewed towards the lower frequency movement (very-low [0.10-0.39Hz] frequency content, p<0.01) and negatively skewed towards moderate frequency movement (moderate [1.56-6.25Hz] frequency content, p=0.012). Sample entropy showed no significant differences between groups (p>0.05). Our results demonstrate that older adults with NP have poorer balance than controls. Furthermore, wavelet analysis may reveal unique insights into postural control mechanisms. Given that centre-of-pressure signal movements in the very-low and moderate frequencies are postulated to be associated with vestibular and muscular proprioceptive input respectively, we speculated that, because NP demonstrate a diminished ability to recruit the muscular proprioceptive system compared to controls, they rely more on the vestibular system for postural stability.

Southern Appalachian peatlands support high archaeal diversity.

Mid-latitude peatlands with a temperate climate are sparsely studied and as such represent a gap in the current knowledge base regarding archaeal populations present and their roles in these environments. Phylogenetic analysis of the archaeal populations among three peatlands in the Southern Appalachians reveal not only methanogenic species but also significant populations of thaumarchaeal and crenarchaeal-related organisms of the uncultured miscellaneous crenarchaeotal group (MCG) and the terrestrial group 1.1c, as well as deep-branching Euryarchaeota primarily within the Lake Dagow sediment and rice cluster V lineages. The Thaum/Crenarchaea and deep-branching Euryarchaea represented approximately 24-83% and 2-18%, respectively, of the total SSU rRNA clones retrieved in each library, and methanogens represented approximately 14-72% of the clones retrieved. Several taxa that are either rare or novel to acidic peatlands were detected including the euryarchaeal SM1K20 cluster and thaumarchaeal/crenarchaeal-related clusters 1.1a, C3, SAGMCG-1, pSL12, and AK59. All three major groups (methanogens, Thaumarchaea/Crenarchaea, and deep-branching Euryarchaea) were detected in the RNA library, suggesting at least a minimum level of maintenance activity. Compared to their northern counterparts, Southern Appalachian peatlands appear to harbor a relatively high diversity of Archaea and exhibit a high level of intra-site heterogeneity.

The effect of Parkinson's disease and levodopa on adaptation of anticipatory postural adjustments.

Postural support alters anticipatory postural adjustments (APAs). Efficient adaptation to changes in postural support in reactive and centrally initiated postural synergies is impaired in Parkinson's disease (PD). This study examined whether APAs are affected differently by familiar and novel supports in people with PD, ON and OFF levodopa. The effect of PD and levodopa on the ability to immediately adapt APAs to changes in support and refine with practice was also investigated. Fourteen people with PD and 14 healthy control participants performed 20 single rapid leg lift tasks in four support conditions: unsupported, bilateral handgrip (familiar), bite plate (novel) and a combined handgrip+bite plate condition. APAs, identified from force plate data, were characterized by an increase in the vertical ground reaction force under the lifted leg as a result of a shift of weight toward the stance limb. Results showed the ability to incorporate familiar and novel external supports into the postural strategy was preserved in PD. Controls and PD patients in the OFF state further refined the postural strategy with practice as evidenced by changes in amplitude of vertical ground reaction forces and forces applied to support apparatus within conditions between the initial and final trials. In the ON state, people with PD failed to refine the use of postural supports in any condition. The results suggest that immediate postural adaptation is intact in people with PD and unaffected by levodopa administration but the ability to refine postural adaptations with task experience is compromised by dopamine therapy.

Stroke management: updated recommendations for treatment along the care continuum.

The Australian Clinical Guidelines for Stroke Management 2010 represents an update of the Clinical Guidelines for Stroke Rehabilitation and Recovery (2005) and the Clinical Guidelines for Acute Stroke Management (2007). For the first time, they cover the whole spectrum of stroke, from public awareness and prehospital response to stroke unit and stroke management strategies, acute treatment, secondary prevention, rehabilitation and community care. The guidelines also include recommendations on transient ischaemic attack. The most significant changes to previous guideline recommendations include the extension of the stroke thrombolysis window from 3 to 4.5 h and the change from positive to negative recommendations for the use of thigh-length antithrombotic stockings for deep venous thrombosis prevention and the routine use of prolonged positioning for contracture management.

Culturable Rhodobacter and Shewanella species are abundant in estuarine turbidity maxima of the Columbia River.

Measurements of dissolved, ascorbate-reducible and total Mn by ICP-OES revealed significantly higher concentrations during estuarine turbidity maxima (ETM) events, compared with non-events in the Columbia River. Most probable number (MPN) counts of Mn-oxidizing or Mn-reducing heterotrophs were not statistically different from that of other heterotrophs (10³ -104 cells ml⁻¹) when grown in defined media, but counts of Mn oxidizers were significantly lower in nutrient-rich medium (13 cells ml⁻¹). MPN counts of Mn oxidizers were also significantly lower on Mn(III)-pyrophosphate and glycerol (21 cells ml⁻¹). Large numbers of Rhodobacter spp. were cultured from dilutions of 10⁻² to 10⁻5, and many of these were capable of Mn(III) oxidation. Up to c. 30% of the colonies tested LBB positive, and all 77 of the successfully sequenced LBB positive colonies (of varying morphology) yielded sequences related to Rhodobacter spp. qPCR indicated that a cluster of Rhodobacter isolates and closely related strains (95-99% identity) represented approximately 1-3% of the total Bacteria, consistent with clone library results. Copy numbers of SSU rRNA genes for either Rhodobacter spp. or Bacteria were four to eightfold greater during ETM events compared with non-events. Strains of a Shewanella sp. were retrieved from the highest dilutions (10⁻5) of Mn reducers, and were also capable of Mn oxidation. The SSU rRNA gene sequences from these strains shared a high identity score (98%) with sequences obtained in clone libraries. Our results support previous findings that ETMs are zones with high microbial activity. Results indicated that Shewanella and Rhodobacter species were present in environmentally relevant concentrations, and further demonstrated that a large proportion of culturable bacteria, including Shewanella and Rhodobacter spp., were capable of Mn cycling in vitro.

Aurantimonas manganoxydans, sp. nov. and Aurantimonas litoralis, sp. nov.: Mn(II) oxidizing representatives of a globally distributed clade of alpha-Proteobacteria from the order Rhizobiales.

Several closely related Mn(II)-oxidizing alpha-Proteobacteria were isolated from very different marine environments: strain SI85-9A1 from the oxic/anoxic interface of a stratified Canadian fjord, strain HTCC 2156 from the surface waters off the Oregon coast, and strain AE01 from the dorsal surface of a hydrothermal vent tubeworm. 16S rRNA analysis reveals that these isolates are part of a tight phylogenetic cluster with previously characterized members of the genus Aurantimonas. Other organisms within this clade have been isolated from disparate environments such as surface waters of the Arctic and Mediterranean seas, a deep-sea hydrothermal plume, and a Caribbean coral. Further analysis of all these strains revealed that many of them are capable of oxidizing dissolved Mn(II) and producing particulate Mn(III/IV) oxides. Strains SI85-9A1 and HTCC 2156 were characterized further. Despite sharing nearly identical 16S rRNA gene sequences with the previously described Aurantimonas coralicida, whole genome DNA-DNA hybridization indicated that their overall genomic similarity is low. Polyphasic phenotype characterization further supported distinguishing characteristics among these bacteria. Thus SI85-9A1 and HTCC 2156 are described as two new species within the family 'Aurantimionadaceae': Aurantimonas manganoxydans sp. nov. and Aurantimonas litoralis sp. nov. This clade of bacteria is widely distributed around the globe and may be important contributors to Mn cycling in many environments. Our results highlight the difficulty in utilizing 16S rRNA-based approaches to investigate the microbial ecology of Mn(II) oxidation.

Age rationing and prudential lifespan account in Norman Daniels' Just health.

Could age be a valid criterion for rationing? In Just health, Norman Daniels argues that under certain circumstances age rationing is prudent, and therefore a morally permissible strategy to tackle the problem of resource scarcity. Crucial to his argument is the distinction between two problem-settings of intergenerational equity: equity among age groups and equity among birth cohorts. While fairness between age groups can involve unequal benefit treatment in different life stages, fairness between birth cohorts implies enjoying approximate equality in benefit ratios. Although both questions of fairness are distinct, the resolution of the one depends on resolution of the other. In this paper, I investigate whether Daniels' account of age rationing could be defended as a fair way of setting limits to healthcare entitlements. I will focus on two main points. First, I will consider whether the age group problem could be resolved without appealing to a conception of the good. Second, I will demonstrate that the connection between the age group problem and the birth cohort problem runs deeper than Daniels initially thought-and that it ultimately suggests a method for prioritisation in problem solving strategies.

Linking stability to demographics, strength and sensory system function in women over 40 to support pre-emptive preventive intervention.

OBJECTIVE: To investigate differences in demographics, strength and sensory system function of 254 women aged 40-80 years categorized as stable, unsteady or unstable using simple balance tests. METHOD: Demographics (age, height, weight, medications, co-morbidities, falls history, activity level), measures of quadriceps, hip abductor and adductor strength, somatosensory, visual and vestibular function were recorded. Subjects were categorized as stable (completed all trials), unsteady (failed one/two trials) or unstable (failed all trials) after three 10-s trials of bilateral stance (foam surface, eyes closed (EC)) and one-leg stance (firm surface, eyes open (EO)), and the results were compared. RESULTS: Both balance tasks identified women in their fifties as unstable ( approximately 9%), with 60% of these women failing both tasks. More women were unsteady or unstable on foam EC (27%) than in one-leg stance EO (20%). Unsteady and unstable categories of women were older, reported more co-morbidities and medications and less activity than stable women. The women categorized as unstable in either test recorded weaker hip muscles, higher vibration thresholds, greater joint positioning error, reduced edge contrast sensitivity, low-contrast visual acuity and reduced dynamic visual acuity than the stable categories (p < 0.01). The two tests detected differences in characteristics of unstable women, with those failing one-leg stance EO being heavier, and those failing foam EC having weaker quadriceps. CONCLUSION: These data link instability in women from the fifties to multiple demographic and sensorimotor factors associated with increased risk of falls, thus supporting use of balance tests in primary-care settings to assist referral for diagnostic assessment and pre-emptive interventions.

Positive effects of exercise on falls and fracture risk in osteopenic women.

UNLABELLED: Exercise may affect osteopenic women at risk of falls and fractures. A workstation approach to exercise was evaluated in a randomised study of 98 women. The intervention group improved in measures of balance, strength and bone density. This study supports a preventative exercise approach that aims to reduce risk factors for fractures and falls, in women already at risk, through balance training and weight-bearing activity. INTRODUCTION: The objective of this study was to determine the effects of a workstation balance training and weight-bearing exercise program on balance, strength and bone mineral density (BMD) in osteopenic women. A single-blinded randomised controlled trial (RCT) was undertaken for 20 weeks with measurements at baseline and completion. MATERIALS AND METHODS: Ninety-eight (98) community-dwelling osteopenic women aged 41-78 years were recruited through the North Brisbane electoral roll. Subjects were randomised via computer-generated random numbers lists into either a control (receiving no intervention), or exercise group (two one-hour exercise sessions per week for 20 weeks with a trained physiotherapist). Assessments at baseline and post-intervention included balance testing (five measures), strength testing (quadriceps, hip adductors / abductors / external rotators and trunk extensors), and DXA scans (proximal femur and lumbar spine). Baseline assessment showed no significant differences between groups for all demographics and measures except for subjects taking osteoporosis medication. The percentage differences between pre- and post-intervention measurements were examined for group effect by ANOVA using an intention-to-treat protocol. RESULTS: Ninety-eight women (mean age 62.01 years, SD 8.9 years) enrolled in the study. The mean number of classes attended for the 42 participants in the exercise group who completed the program was 28.2 of a possible 40 classes (71%). At the completion of the trial the intervention group showed markedly significant better performances in balance (unilateral and bilateral stance sway measures, lateral reach, timed up and go and step test) (p < 0.05) with strong positive training effects reflecting improvements of between 10% to 71%. Similarly there were gains in strength of the hip muscles (abductors, adductors, and external rotators), quadriceps and trunk extensors with training effects between 9% and 23%. CONCLUSIONS: Specific workstation exercises can significantly improve balance and strength in osteopenic women. This type of training may also positively influence bone density although further study is required with intervention over a longer period. A preventative exercise program may reduce the risk of falls and fractures in osteopenic women already at risk.

Breath alcohol concentration determined with a new analyzer using free exhalation predicts almost precisely the arterial blood alcohol concentration.

A new breath alcohol (ethanol) analyzer has been developed, which allows free exhalation, standardizes measured exhaled alcohol concentration to fully saturated water vapor at a body temperature of 37 degrees C (43.95 mg/L) and includes a built-in self-calibration system. We evaluated the performance of this instrument by comparing standardized alcohol concentration in freely expired breath (BrAC) with arterial (ABAC) and venous (VBAC) blood alcohol concentrations in fifteen healthy volunteers who drank 0.6 g of alcohol per kg body weight. The precision (coefficient of variation, CV) of the analyzer based on in vivo duplicate measurements in all phases of the alcohol metabolism was 1.7%. The ABAC/BrAC ratio was 2251+/-46 (mean+/-S.D.) in the post-absorptive phase and the mean bias between ABAC and BrAC x 2251 was 0.0035 g/L with 95% limits of agreement of 0.033 and -0.026. The ABAC and BrAC x 2251 were highly correlated (r=0.998, p<0.001) and the regression relationship was ABAC = 0.00045 + 1.0069 x (BrAC x 2251) indicating excellent agreement and no fixed or proportional bias. In the absorption phase, ABAC exceeded BrAC x 2251 by at most 0.04+/-0.03 g/L when tests were made at 10 min post-dosing (p<0.05). The VBAC/BrAC ratio never stabilized and varied continuously between 1834 and 3259. There was a proportional bias between VBAC and BrAC x 2251 (ABAC) in the post-absorptive phase (p<0.001). The pharmacokinetic analysis of the elimination rates of alcohol and times to zero BAC confirmed that BrAC x 2251 and ABAC agreed very well with each other, but not with VBAC (p<0.001). We conclude that this new breath analyzer using free exhalation has a high precision for in vivo testing. The BrAC reflects very accurately ABAC in the post-absorption phase and substantially well in the absorption phase and thereby reflects the concentration of alcohol reaching the brain. Our findings highlight the magnitude of arterio-venous differences in alcohol concentration and support the use of breath alcohol analyzers as a stand-alone test for medical and legal purposes.

Upper limb recovery after stroke: the stroke survivors' perspective.

PURPOSE: This study investigated stroke survivors' perspective of upper limb recovery after stroke. The aim was to determine factors other than medical diagnosis and co-morbidities that contribute to recovery. The objectives were to explore how stroke survivors define recovery, identify factors they believe influence recovery and determine strategies used to maximize upper limb recovery. METHOD: A qualitative study consisting of three focus groups and two in-depth interviews was conducted with stroke survivors (n = 19) and spouses (n = 9) in metropolitan, regional and rural Queensland, Australia. Data were analysed using principles of grounded theory. RESULTS: Stroke survivors maximize upper limb recovery by 'keeping the door open' a process of continuing to hope for and work towards improvement amidst adjusting to life with stroke. They achieve this by 'hanging in there', 'drawing on support from others', 'getting going and keeping going with exercise', and 'finding out how to keep moving ahead'. CONCLUSIONS: This study provides valuable insight into the personal experience of upper limb recovery after stroke. It highlights the need to develop training strategies that match the needs and aspirations of stroke survivors and that place no time limits on recovery. It reinforces the benefits of stroke support groups and advocates their incorporation into stroke recovery services. These findings can be used to guide both the development and evaluation of stroke survivor centred upper limb training programmes.

Simplest tasks have greatest dual task interference with balance in brain injured adults.

Attention difficulties and poor balance are both common sequel following a brain injury. This study aimed to determine whether brain injured adults had greater difficulty than controls in performing a basic balance task while concurrently completing several different cognitive tasks varying in visuo-spatial attentional load and complexity. Twenty brain injured adults and 20 age-, sex- and education level-matched controls performed a balance-only task (step stance held for 30 s), five cognitive-only tasks (simple and complex non-spatial, visuo-spatial, and a control articulation task), and both together (dual tasks). Brain injured adults showed a greater centre of pressure (COP) excursion and velocity in all conditions than controls. Brain injured adults also demonstrated greater interference with balance when concurrently performing two cognitive tasks than control subjects. These were the control articulation and the simple non-spatial task. It is likely that distractibility during these simple tasks contributed to an increase in COP motion and interference with postural stability in stance. Performing visuo-spatial tasks concurrently with the balance task did not result in any change in COP motion. Dual task interference in this group is thus unlikely to be due to structural interference. Similarly, as the more complex tasks did not uniformly result in increased interference, a reduction in attentional capacity in the brain injured population is unlikely to be the primary cause of dual task interference in this group.

Investigation of hip abductor activation in subjects with clinical unilateral hip osteoarthritis.

OBJECTIVES: (a) To compare the magnitude of gluteus medius and tensor fascia lata activation between a group of subjects with clinical unilateral hip osteoarthritis and a group of healthy older adults. (b) To compare the magnitude of activation of the gluteus medius and tensor fascia lata between sides in a group of subjects with clinical unilateral hip osteoarthritis and a group of healthy older adults. METHODS: 19 subjects with clinical unilateral hip osteoarthritis and 19 healthy controls were investigated. The subjects performed a stepping task during which recordings were obtained using surface electromyograms from the hip abductors, and kinetic data were obtained from a dual force platform. RESULTS: Subjects with clinical hip osteoarthritis had higher gluteus medius activation than the healthy older adults (p=0.037). In addition, there were no differences in the magnitude of gluteus medius activation between the sides (p=0.733). There was no difference in the force platform data between the groups (p=0.078). CONCLUSIONS: The increased magnitude of gluteus medius activation in the group with hip osteoarthritis is evidence of a muscular dysfunction associated with hip disease. This has implications for the progressive nature of the disease and for its conservative management.

The influence of a concurrent cognitive task on the compensatory stepping response to a perturbation in balance-impaired and healthy elders.

This study investigated the influence of a concurrent cognitive task on the compensatory stepping response in balance-impaired elders and the attentional demand of the stepping response. Kinetic, kinematic and neuromuscular measures of a forward recovery step were investigated in 15 young adults, 15 healthy elders and 13 balance-impaired elders in a single task (postural recovery only) and dual task (postural recovery and vocal reaction time task) situation. Results revealed that reaction times were longer in all subjects when performed concurrently with a compensatory step, they were longer for a step than an in-place response and longer for balance-impaired older adults compared with young adults. An interesting finding was that the latter group difference may be related to prioritization between the two tasks rather than attentional demand, as the older adults completed the step before the reaction time, whereas the young adults could perform both concurrently. Few differences in step characteristics were found between tasks, with the most notable being a delayed latency and reduced magnitude of the early automatic postural response in healthy and balance-impaired elders with a concurrent task.

The interacting effects of cognitive demand and recovery of postural stability in balance-impaired elderly persons.

BACKGROUND: Although postural recovery is attentionally demanding in healthy elderly persons, an inability to recover balance due to competition for attentional resources between the postural system and a second task could contribute to falls in older adults with poor balance. This study examined the attentional demands of balance recovery from a mild postural disturbance in balance-impaired elderly persons. A second purpose of this research was to determine the effect of performing a cognitive task on the recovery of balance in balance-impaired elderly persons. METHODS: Fifteen healthy older adults and 13 older adults with clinical balance impairment were exposed to balance disturbances by means of sudden movement of a platform on which they stood. A dual-task paradigm where postural recovery served as the primary task and verbal reaction time to auditory tones served as the secondary task was used to assess attentional demand. To determine the effect of the cognitive task on postural recovery, kinetic, kinematic, and neuromuscular measures of a feet-in-place response were investigated. RESULTS: Balance recovery using a feet-in-place response was attentionally demanding in both groups of older adults and was more demanding in balance-impaired than in healthy elderly persons. With the concurrent performance of a cognitive task, balance-impaired elderly persons took longer to stabilize their center of pressure and regain balance than in a single task, while healthy elderly persons showed no change between conditions. In addition, only balance-impaired elderly individuals had a greater center-of-pressure resultant velocity during recovery in a dual-task compared with a single-task situation. CONCLUSIONS: The ability to recover balance using a feet-in-place response was more attentionally demanding in balance-impaired than in healthy elderly persons. The recovery of balance was also slower and less efficient in balance-impaired elderly persons when simultaneously performing a cognitive task, whereas the ability of healthy elderly individuals to recover was not influenced by concurrent task demands. This suggests that dual-task performance may contribute to postural instability and falls in balance-impaired elderly individuals.