Postural control entropy is increased when adopting an external focus of attention

Falls in older adults are a public health challenge due to their influence on well-being and health-care costs. One way to address this challenge is to discover new methods to enhance postural control in older adults so they are better prepared to maintain an upright stance. Older and younger adults (N?=?32) performed a static balance task on a force plate with no instructions, internal focus instructions, or external focus instructions. Center of pressure displacement time series were analyzed using sample entropy and standard deviation. Only the external focus condition significantly increased postural control entropy, which was observed across both age groups. This study showed that an external focus of attention can be used to increase postural control entropy within a single session of testing

The effect of signal acquisition and processing choices on ApEn values: Towards a “gold standard” for distinguishing effort levels from isometric force records

Approximate Entropy (ApEn) is frequently used to identify changes in the complexity of isometric force records with ageing and disease. Different signal acquisition and processing parameters have been used, making comparison or confirmation of results difficult. This study determined the effect of sampling and parameter choices by examining changes in ApEn values across a range of submaximal isometric contractions of the First Dorsal Interosseus. Reducing the sample rate by decimation changed both the value and pattern of ApEn values dramatically. The pattern of ApEn values across the range of effort levels was not sensitive to the filter cut-off frequency, or the criterion used to extract the section of data for analysis. The complexity increased with increasing effort levels using a fixed ‘r’ value (which accounts for measurement noise) but decreased with increasing effort level when ‘r’ was set to 0.1 of the standard deviation of force. It is recommended isometric force records are sampled at frequencies >200 Hz, template length (‘m’) is set to 2, and 'r' set to measurement system noise or 0.1 SD depending on physiological process to be distinguished. It is demonstrated that changes in ApEn across effort levels are related to changes in force gradation strategy

Human Movement Variability and Aging

An optimal level of variability enables us to interact adaptively and safely to a continuously changing environment, where often our movements must be adjusted in a matter of milliseconds. A large body of research exists that demonstrates natural variability in healthy gait (along with variability in other, healthy biological signals such as heart rate) and a loss of this variability in aging and injury, as well as in a variety of neurodegenerative and physiological disorders. We submit that this field of research is now in pressing need of an innovative “next step” that goes beyond the many descriptive studies that characterize levels of variability in various patient populations. We need to devise novel therapies that will harness the existing knowledge on biological variability and create new possibilities for those in the grip of disease. We also propose that the nature of the specific physiological limitation present in the neuromuscular apparatus may be less important in the physiological complexity framework than the control mechanisms adopted by the older individual in the coordination of the available degrees of freedom. The theoretical underpinnings of this framework suggest that interventions designed to restore healthy system dynamics may optimize functional improvements in older adults. We submit that interventions based on the restoration of optimal variability and movement complexity could potentially be applied across a range of diseases or dysfunctions as it addresses the adaptability and coordination of available degrees of freedom, regardless of the internal constraints of the individual

Evaluation of Current Emergency Department Fall Risk Assessment Tools: Is An Emergency Department Specific Fall Risk Assessment Tool Needed?

Problem: The ability to accurately and quickly identify patients at high risk for falls at the point of entry into the emergency department is the most important step in fall prevention and avoiding harm. Using an inpatient falls risk assessment tool is not adequately identifying patients at risk in the emergency department setting. Multiple factors contribute to falls and are not included in the risk assessment tool. The purpose of the study was to determine if the false risk assessment tool used in the Emergency Department (ED) adequately identifies a patient at risk for falling. Methods: This study used a snowball sampling method via Facebook with a link to Survey Monkey. Results: Of the 72 nurses who completed the survey, 34.7% of the nurses thought the survey was not appropriate for the evaluation of falls in the emergency department. Even though this may not seem like many, of those 72 nurses, 47.2% of them would prefer a simpler tool. When asked what population of patients the fall risk assessment tool did not appropriately screen for, responses included intoxicated, pediatric, infants, substance abuse, dizziness, vertigo, and unconscious patients. Implication for Practice: After reviewing the literature, it would be beneficial to develop an ED fall risk assessment tool that is specific to the patient population in the emergency department. A possible future study would be to implement an ED specific fall risk assessment tool and determine the effectiveness of the risk assessment tool on predicting patient falls. Key Words: Falls, Fall risk tool, Emergency room specific falls too

A Review of Frailty Syndrome and Its Physical, Cognitive and Emotional Domains in the Elderly

Peer reviewedPublisher PD

Gait Variability Measures Reveal Differences between Multiple Sclerosis Patients and Healthy Controls

The purpose of this study was to determine the differences in gait variability between patients with multiple sclerosis (MS) and healthy controls during walking at a self-selected pace. Methods: Kinematics were collected during three minutes of treadmill walking for 10 patients with MS and 10 healthy controls. The Coefficient of Variation (CoV), the Approximate Entropy (ApEn) and the Detrended Fluctuation Analysis (DFA) were used to investigate the fluctuations present in stride length and step width from continuous strides. Results: ApEn revealed that patients with MS had significantly lower values than healthy controls for stride length (p \u3c .001) and step width (p \u3c .001). Conclusions: ApEn results revealed that the natural fluctuations present during gait in the stride length and step width time series are more regular and repeatable in patients with MS. These changes implied that patients with MS may exhibit reduced capacity to adapt and respond to perturbations during gait

Dynamic transcranial Doppler assessment in Heart Failure patients

Insuficiência cardíaca (IC) é uma doença prevalente, mas pouco é compreendido em relação às suas repercussões nos mecanismos hemodinâmicos cerebrais e declínio cognitivo. Monitorizamos a velocidade de fluxo sanguíneo cerebral (VFSC) com Doppler transcraniano em doentes com IC e controlos saudáveis. Autorregulação cerebral (AC) foi calculada através da função transferência das oscilações espontâneas da pressão arterial para o VFSC e vasorreatividade (VR) com a inalação de CO2 a 5% e hiperventilação. MoCA foi calculado e associado a cada componente regulatório cerebrovascular. Nenhuma diferença foi detetada na VR. Pacientes com IC revelaram uma melhor resposta na AC. (Artéria Cerebral média (ACM): ganho na Frequência muito baixa (FMB) 0.47±0.15 vs 0.88±0.19 %/mmHg, p=0.001; ganho na Frequência Baixa (FB) 0.60±0.23 vs 1.28±0.05 %/mmHg, p=0.000; fase na FMB 2.05±0.59 vs 1.12±0.12 radianos, p=0.021; Artéria Cerebral Posterior (ACP): ganho na FMB 0.47±0.25 vs 1.11±0.24 %/mmHg, p=0.000; ganho na FB 0.66±0.32 vs 1.83±0.45 %/mmHg, p=0.000). Nenhum parâmetro cerebrovascular correlacionou significativamente com o score MoCA. A hemodinâmica cerebrovascular poderá ter um papel importante na abordagem adequada aos doentes com IC.Heart failure (HF) is a prevalent disease but few is understood in its repercussion in cerebral hemodynamics mechanisms and cognitive decline. We monitored cerebral blood flow velocity (CBFV) with transcranial Doppler in HF patients and healthy controls. Cerebral autoregulation (CA) was assessed by transfer function from the spontaneous oscillations of blood pressure to CBFV and vasoreactivity (VR) with inhalation of CO2 at 5% and hyperventilation. MoCA was measured and associated with each cerebrovascular regulatory component. No differences were detected in VR. HF patients showed a better CA response. (Middle cerebral artery (MCA): very low frequency (VLF) gain 0.47±0.15 vs 0.88±0.19 %/mmHg, p=0.001; low frequency (LF) gain 0.60±0.23 vs 1.28±0.05 %/mmHg, p=0.000; VLF phase 2.05±0.59 vs 1.12±0.12 radians, p=0.021; Posterior cerebral artery (PCA): VLF gain 0.47±0.25 vs 1.11±0.24 %/mmHg, p=0.000; LF gain 0.66±0.32 vs 1.83±0.45 %/mmHg, p=0.000). None of the cerebrovascular parameters correlated significantly with MoCA score. Cerebrovascular hemodynamics could have a major role in the proper management of HF patients