The Effects of Virtual Reality Based Rehabilitation on Upper Extremity Function in a Child with Cerebral Palsy: A Case Report.

AIM: This case report was designed to assess the efficacy of virtual reality (VR) rehabilitation on improving upper extremity function for a child with spastic hemiplegic cerebral palsy. METHODS: In addition to conventional therapies completed three times per week, the participant engaged in virtual reality rehabilitation with the Neofect Smart Kids five to seven days per week for six weeks totaling just over twelve hours of intervention time. Outcome measures were administered pre-intervention, post-intervention, and 6-weeks post-intervention. RESULTS: Varying levels of improvement in motor function, quality of movement, and functional use were observed during intervention evidenced by improved scores on the following standardized assessments: Peabody Developmental Motor Scales, Second Edition; the Quality of Upper Extremity Skills Test; and the Pediatric Evaluation and Disability Inventory-Computer Adaptive Test. The participant maintained improvements in motor skills at 6-weeks post intervention, however, the quality of his movements and overall frequency of use with his affected upper extremity decreased in the 6-weeks following termination of intervention. CONCLUSIONS: Even though the results are not generalizable, the VR intervention for this child allowed for greater movement repetition and improved functional upper extremity use.

Visual and somatosensory contributions to infant sitting postural control.

There are a limited number of studies that have investigated sitting posture during infancy and the contribution of the sensory systems. The goal of this study was to examine the effects of altered visual and somatosensory signals on infant sitting postural control. Thirteen infants (mean age ± SD, 259.69 ± 16.88 days) participated in the study. Initially, a single physical therapist performed the Peabody Developmental Motor Scale to determine typical motor development. Then the child was placed onto a force platform under four randomized conditions: (a) Control (C) - sat independently on the force plate, (b) Somatosensory (SS) - Sat independently on a foam pad (low density), (c) Visual (VS) - sat independently on the force plate while the lights were turned off creating dim lighting, and (d) Combination of b and c (NVSS). Center of pressure (COP) data from both the anterior-posterior (AP) and the medial-lateral (ML) directions were acquired through the Vicon software at 240 Hz. The lights off conditions, both VS and NVSS, lead to increased Root Mean Square (RMS) and Range values in the AP direction, as well as increased Lyapunov Exponent (LyE) values in the ML direction. Altered visual information lead to greater disturbances of sitting postural control in typically developing infants than altered somatosensory information. The lights off conditions (VS and NVSS), unveiled different control mechanisms for AP and ML direction during sitting. Thus, the present findings confirm the dominance of vision during the early acquisition of a new postural accomplishment.

An overview of assessment methodology for obesity-related variables in infants at risk.

BACKGROUND: The first 2 years of a child's life are a particularly critical time period for obesity prevention. AIM: An increasing amount of research across the world is aimed at understanding factors that impact early childhood obesity and developing interventions that target these factors effectively. With this growing interest, new and interdisciplinary research teams are developing to meet this research need. Due to rapid growth velocity during this phase of the lifespan, typical assessments used in older populations may not be valid or applicable in infants, and investigators need to be aware of the pros and cons of specific methodological strategies. METHODS: This paper provides an overview of methodology available to assess obesity-related factors in the areas of anthropometry and body composition, nutrient intake, and energy expenditure in infants aged 0-2 years. RESULTS: Gold standard measures for body composition, such as dual-energy X-ray absorptiometry (DXA) or other imaging techniques, are costly, require highly trained personnel, and are limited for research application. Nutrient intake methodology primarily includes surveys and questionnaires completed via parent proxy report. In terms of energy expenditure, methods of calorimetry are expensive and may not differentiate between different activities. Questionnaires or physical activity sensors offer another way of energy expenditure assessment. However, questionnaires have a certain recall bias, while the sensors require further validation. CONCLUSIONS: Overall, in addition to understanding the pros and cons of each assessment tool, researchers should take into consideration the experience of the interdisciplinary team of investigators, as well as the cost and availability of measures at their institution.

Infant sitting postural control appears robust across changes in surface context.

AIM OF THE STUDY: Independent sitting requires the control of the involved body segments over the base of support using information obtained from the three sensory systems (visual, vestibular, and somatosensory). The contribution of somatosensory information in infant sitting has not been explored. To address this gap, we altered the context of the sitting support surface and examined the infants' immediate postural responses. MATERIALS AND METHODS: Ten 7-month-old typically developing infants sat on compliant and firm surfaces in one session. Spatial, frequency, and temporal measures of postural control were obtained using center of pressure data. Results Our results suggest that infants' postural sway is not immediately affected by the different types of foam surface while sitting. CONCLUSIONS: It seems that mature sitter infants are able to adapt to different environmental constraints by disregarding the distorted somatosensory information from the support surface and relying more on their remaining senses (visual and vestibular) to control their sitting posture.

He's just content to sit: a qualitative study of mothers' perceptions of infant obesity and physical activity.

BACKGROUND: Rates of obesity among children ages zero to five are rapidly increasing. Greater efforts are needed to promote healthy behaviors of young children. Mothers are especially important targets for promoting health as mothers' views play a vital role in helping their children foster healthy habits from an early age. Research has found parents' views of infants' weight may influence their feeding practices; however, limited research has explored mothers' view of infants' weight in relation to the promotion of physical activity. Therefore, the purpose of this study was to explore the perceptions of mothers of normal weight infants and overweight infants about their infant's weight and physical activity. METHODS: Semi-structured interviews were conducted with mothers of normal weight (n = 18) and of overweight (n = 11) infants (6.5 ± 0.5 month) in a Midwestern city in the United States. A thematic analysis was used to analyze the data. RESULTS: A majority of mothers thought infants could be overweight. However, no mothers referenced their own infant as overweight. Mothers most commonly noted infants could be overweight only if they were formula fed and/or were overfed, not if they were breastfed. Mothers views were not negatively influenced by others who mentioned that their child was either "big" or "small" and only one mother had been told her infant was overweight. A majority of mothers thought an infant could be physically active. When discussing infant activity, mothers primarily referred to it in terms of general mobility and a few thought activity level was related to a personality characteristic. Mothers intended to promote physical activity in the future either through outdoor play or specific organized activities such as sports. Despite a majority of mothers stating they were currently physically active themselves, only a few talked about interacting with their infant to promote their infant's physical activity. CONCLUSIONS: Efforts are needed by healthcare professionals and other public health professionals to inform mothers about the dangers of increased weight during infancy as well as the importance of interacting with infants to promote physical activity.

The effects of verbal cues on EMG activity during a quadriceps setting exercise.

CONTEXT: A quadriceps setting (quad set) exercise is commonly utilized following knee injury, but there is great variation in cues that clinicians provide to patients when performing the exercise. OBJECTIVES: To determine if internal, external, or visual cues results in the greatest quadriceps electromyographical (EMG) activity during a quadriceps setting exercise in healthy individuals. DESIGN: Descriptive laboratory study. SETTING: University research laboratory. PARTICIPANTS: Thirty healthy individuals volunteered for this study. Participants were given one of five cues in a randomized order: internal cue "tighten your thigh muscles," internal cue "push your knee down," external cue "push into the bolster," external cue "push into the strap," or visual biofeedback using the cue "raise the value on the screen as high as you can." MAIN OUTCOME MEASURES: Normalized vastus lateralis EMG activity. RESULTS: Both visual biofeedback (83.2±24.9%) and "press into the strap" (76.8±24.4%) produced significantly greater (p< 0.001) EMG activity than the push knee down (53.2±27.0%), tighten thigh (52.7±27.3%), or push into the bolster (50.8±26.3) conditions. There was no significant difference (p= 0.10) between the visual biofeedback and "press into the strap" conditions as well as no significant difference (p> 0.38) between the push knee down, tighten thigh, or push into the bolster conditions. CONCLUSIONS: If the clinical aim during a quadriceps setting exercise is to obtain the greatest volitional muscle recruitment, the use of visual biofeedback or pressing into a strap is recommended.

Sitting postural control in infants with typical development, motor delay, or cerebral palsy.

PURPOSE: To determine whether infants born full-term, infants born preterm with motor delays, and infants born preterm who have a diagnosis of cerebral palsy (CP) differed in postural control at the emergence of early sitting. METHODS: Thirty infants born at term who were developing typically, 6 infants born preterm who were later diagnosed with CP, and 5 infants born preterm who were delayed in motor development participated in this study. Center-of-pressure data from unsupported sitting were recorded and analyzed using measures of both amount and temporal organization of center-of-pressure variability. RESULTS: Infants born full-term, infants born preterm with motor delays, and infants born preterm who have a diagnosis of CP exhibited dissimilar movement-control strategies at the onset of sitting. CONCLUSIONS: The present findings may be helpful in directing and testing intervention protocols for infants born preterm.

Development of Infant Sitting Postural Control in Three Groups of Infants at Various Risk Levels for Autism Spectrum Disorder.

The purpose of this study was to examine the development of sitting postural control among two groups of infants at elevated risk for autism spectrum disorders (ASD) and a group of infants at typical risk for ASD and its association with cognitive, language and communication skills at a later age. We visited infants in their home environment from the onset of sitting until sitting independence and at 12 and 18 months of age. We collected data on sitting posture (center of pressure), through a portable force platform, as well as communication, cognitive and social behavior assessments at various time points. Our results showed that postural control differences at the onset of sitting, were present among the groups of infants but there were no statistically significant differences among the groups in the development of sitting posture. In addition, there were statistically significant communication differences among the groups and mostly the change in sample entropy in the anterior/posterior direction (posture measure) was significantly correlated with other skills at a later age. This study highlights the importance of investigating multiple at-risk groups to identify unique developmental pathways that may lead to an ASD diagnosis.

Training dual-task walking in community-dwelling adults within 1 year of stroke: a protocol for a single-blind randomized controlled trial.

BACKGROUND: Community ambulation is a highly complex skill requiring the ability to adapt to increased environmental complexity and perform multiple tasks simultaneously. After stroke, individuals demonstrate a diminished ability to perform dual-tasks. Current evidence suggests that conventional rehabilitation does not adequately address gait-related dual-task impairments after stroke, which may be contributing to low levels of participation and physical inactivity in community-dwelling stroke survivors. The objective of this study is to investigate the efficacy of dual-task gait training in community-dwelling adults within 1 year of stroke. Specifically, we will compare the effects of dual-task gait training and single-task gait training on cognitive-motor interference during walking at preferred speed and at fastest comfortable speed (Aim 1), locomotor control during obstacle negotiation (Aim 2), and spontaneous physical activity (Aim 3). METHODS/DESIGN: This single-blind randomized controlled trial will involve 44 individuals within 12 months of stroke. Following baseline evaluation, participants will be randomly allocated to single- or dual-task gait training. Both groups will receive 12, 30-minute sessions provided one-on-one over 4-6 weeks in an outpatient therapy setting. Single-task gait training involves practice of gait activities incorporating motor relearning principles. Dual-task gait training involves an identical gait training protocol; the critical difference being that the dual-task gait training group will practice the gait activities while simultaneously performing a cognitive task for 75% of the repetitions. Blinded assessors will measure outcomes at baseline, post-intervention, and 6 months after completion of the intervention. The primary outcome measure will be dual-task effects on gait speed and cognition during unobstructed walking. Secondary outcomes include spatiotemporal and kinetic gait parameters during unobstructed single- and dual-task walking at preferred and fastest comfortable walking speeds, gait parameters during high and low obstacle crossing, spontaneous physical activity, executive function, lower extremity motor function, Timed Up and Go, balance self-efficacy, number of falls, and stroke-related disability. Hypotheses for each aim will be tested using an intention-to-treat analysis with repeated measures ANOVA design. DISCUSSION: This trial will provide evidence to help clinicians make decisions about the types of activities to include in rehabilitation to improve dual-task walking after stroke. TRIAL REGISTRATION: ClinicalTrials.gov NCT01568957.

Center of pressure characteristics differ during single leg stance throughout pregnancy and compared to nulligravida individuals.

BACKGROUND: Falls are common during pregnancy and present potential for injury to the pregnant individual and the baby. RESEARCH QUESTION: Do center of pressure characteristics during single leg stance differ between participants during and after pregnancy and nulligravida participants in the presence and absence of visual input? METHODS: Nineteen pregnant participants completed testing during the second trimester, the third trimester, and 4-6 months post-partum. Matched, nulligravida females completed testing once. All participants performed single leg stance on a force platform on each limb for up to 20 s with eyes open and with eyes closed. Center of pressure characteristics were compared between pregnant and nulligravida females using three separate 2 × 2 mixed way ANOVAs, one for each pregnancy time point (second trimester, third trimester, and post-partum) with Bonferroni correction. RESULTS: Pregnant females demonstrated smaller single leg stance time with eyes closed during the third trimester. During the second and third trimester, pregnant participants demonstrated smaller sway and sway velocity across eyes open and eyes closed conditions. During the third trimester and post-partum, pregnant participants demonstrated greater median frequency of the center of pressure data. Pregnant participants also demonstrated smaller sample entropy in the anteroposterior direction during the second and third trimesters and in the mediolateral direction during the second trimester. SIGNIFICANCE: The decreased total sway and sway velocity observed during pregnancy may reflect rigidity or a protective strategy during single limb stance. Additionally, center of pressure data were less smooth and more repetitive during pregnancy indicating robust differences in postural control strategies and potentially increased fall risk. Because single limb stance is a component of many activities of daily living, the single limb stance task may have clinical utility for testing or training balance in this population with a goal of decreasing falls.

A home-based longitudinal study of vocalization behaviors across infants at low and elevated risk of autism.

Background and Aims: The purpose of this exploratory study was to expand existing literature on prelinguistic vocalizations by reporting results of the first home-based longitudinal study examining a wide variety of behaviors and characteristics, including early vocalizations, across infants at low and elevated risk of autism spectrum disorder (ASD). The study of vocalizations and vocalization changes across early developmental periods shows promise in reflecting early clinically significant differences across infants at low and elevated risk of ASD. Observations of early vocalizations and their differences during infancy could provide a reliable and essential component of an early developmental profile that would lower the average diagnostic age for ASD. However, studies employing observation of vocalization behaviors have been limited and often conducted in laboratory settings, reducing the external generalization of the findings. Methods: The present study was conducted to determine the consistency of previous findings with longitudinal data collected in home environments. Infants in the present study represented elevated risk from two etiological backgrounds, (a) infants born prematurely and with low birth weight and (b) infants who had an older sibling diagnosed with ASD. All data were collected in the infants' homes and compared with data collected from infants with low likelihood of ASD. The study included 44 participants (31 in the low-risk sample, 13 in the high-risk sample) with vocalization behaviors observed at 6- and 12-months through 20-min semi-structured play interactions with caregivers. Observations were video-recorded and later coded for speech and non-speech vocalizations. Results: Differences in the 6-month vocalization behaviors were not statistically significant across risk levels of ASD. By 12 months; however, risk group differences were evident in the total number of vocalizations overall with specific differences across groups representing moderate to large, clinically relevant effects. Infants at low risk of ASD demonstrated significantly greater developmental change between 6- and 12-months than did the infants at high risk. Data were also reviewed for differences across high-risk group etiologies. Conclusions: The present study was unique and innovative in a number of ways as the first home-based longitudinal study examining infant vocal behaviors across low and high risk of ASD. Many of the present study findings were consistent with previous cross-sectional investigations of infants at elevated risk for ASD, indicating support for further home-based longitudinal study in this area. Findings also indicated some preliminary subgroup differences between high-risk etiologies of ASD. Vocalization differences across high risk groups had not been previously addressed in the literature. Implications: Vocalization differences are notable by 12-months of age between infants at low and elevated risk of ASD and infants at high risk demonstrated reduced developmental changes between 6- and 12-months compared to the infants at low risk. Observation of early infant vocalization behaviors may reasonably occur in the home, providing early childhood professionals and researchers with empirical support for data collection of child-caregiver interactions in this setting. Potential differences across high-risk etiologies warrant further investigation.

Postural control may drive the development of other domains in infancy.

BACKGROUND: To examine differences in sitting posture in infants at low- and high-risk for autism spectrum disorder and to establish the relationship between sitting postural control and other developmental domains. METHODS: A total of 19 infants participated in the study. Eight infants at high-risk and 11 infants at low-risk for autism spectrum disorder. Sitting posture at 6 months was evaluated using a force platform while center of pressure data were acquired. We utilized traditional tools of center of pressure analysis, such as range, median frequency and frequency dispersion, as well as non-linear tools such as Sample Entropy for both the medial-lateral and anterior-posterior directions. At 12 months we used the Mullen Scales of Early Learning, the Communication and Symbolic Behavior Scales Developmental Profile™ and the Ages and Stages Questionnaire, the personal-social subscale. FINDINGS: At 6 months none of the postural control measures showed statistically significant differences between groups. Infants at high-risk presented significantly lower scores in all behavioral domains than infants at low-risk at 12 months with fair effect sizes. Certain measures of postural control at 6 months could predict language and visual reception behavior at 12 months. INTERPRETATION: Infants at high-risk for autism spectrum disorder present with delays in social, communication and language behavior as well as altered postural control in the first year of life. The present data support the possibility that motor skills and specifically postural control may drive the development in other domains.

Reliability of center of pressure measures for assessing the development of sitting postural control in infants with or at risk of cerebral palsy.

OBJECTIVE: To establish the test-retest reliability of linear and nonlinear measures, including intra- and intersession reliability, when used to analyze the center of pressure (COP) time series during the development of infant sitting postural control in infants with or at risk for cerebral palsy (CP). DESIGN: Longitudinal study. SETTING: University hospital laboratory. PARTICIPANTS: Infants with or at risk for CP (N=18; mean age ± SD at entry into the study, 13.7±3.6mo). INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURES: Infant sitting COP data were recorded for 3 trials at each session (2 sessions for each month within 1 week) for 4 consecutive months. The linear COP parameters of the root mean square, the range of sway for both the anterior-posterior and the medial-lateral directions, and the sway path were calculated. In addition, the nonlinear parameters of approximate entropy, Lyapunov exponent (LyE), and the correlation dimension for both directions were also calculated. Intra- and intersession reliability was computed by the intraclass correlation coefficient (ICC). RESULTS: Regarding nonlinear measures, LyE showed high intra- and intersession ICC values in comparison with all other parameters evaluated. Intrasession and intersession reliability increased overall in the last 2 months of data collection and as sitting posture improved. CONCLUSIONS: Our results suggested that the methodology presented is a reliable way of examining the development of sitting postural control in infants with or at risk for CP, and the reliability results generally parallel values found in sitting postural behavior in typical infants. Therefore, this methodology may be helpful in examining efficacy of therapy protocols directed at advancing sitting postural control in infants with motor developmental delays.

Severity and characteristics of developmental delay can be assessed using variability measures of sitting posture.

PURPOSE: We sought to identify measures of variability from sitting postural sway that are significantly different among infants who were developing typically, those who were developmentally delayed or hypotonic, and those who later on had a diagnosis of spastic or athetoid cerebral palsy. METHODS: Sixty-five infants were evaluated when they were just developing the ability to sit upright by assessing center of pressure (COP) data, using measures of both amount and temporal organization of COP variability. RESULTS: The results indicated that measures of variability of COP could discriminate between infants with developmental delay and infants with cerebral palsy and add to the description of sitting postural behavior. CONCLUSIONS: Our method of evaluating sitting postural control could be an objective tool to help describe distinctive features of motor delay in an individual infant and could lead in the design of selective therapeutic interventions for improving postural control of infants with motor delays.

Development of upper body coordination during sitting in typically developing infants.

Our goal was to determine how the actions of the thorax and the pelvis are organized and coordinated to achieve independent sitting posture in typically developing infants. The participants were 10 typically developing infants who were evaluated longitudinally from first onset of sitting until sitting independence. Each infant underwent nine testing sessions. The first session included motor evaluation with the Peabody test. The other eight sessions occurred over a period of 4 mo where sitting behavior was evaluated by angular kinematics of the thorax and the pelvis. A physical therapist evaluated sitting behavior in each session and categorized it according to five stages. The phasing relationship of the thorax and the pelvis was calculated and evaluated longitudinally using a one-way analysis of variance. With development, the infants progressed from an in-phase (moving in the same direction) to an out-of-phase (moving in an opposite direction) coordinative relationship between the thorax and the pelvis segments. This change was significant for both sagittal and frontal planes of motion. Clinically, this relationship is important because it provides a method to quantify infant sitting postural development, and can be used to assess efficacy of early interventions for pediatric populations with developmental motor delays.

Reliability of center of pressure measures for assessing the development of sitting postural control.

OBJECTIVES: To determine the reliability of linear and nonlinear tools, including intrasession and intersession reliability, when used to analyze the center of pressure (COP) time series during the development of infant sitting postural control. DESIGN: Longitudinal study. SETTING: University hospital laboratory. PARTICIPANTS: Typically developing infants (N=33; mean +/- SD age at entry in the study, 152.4+/-17.6d). INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURES: Infants were tested twice in 1 week at each of the 4 months of the study. Sitting COP data were recorded for 3 trials at each session (2 each month within 1 week). The linear COP parameters of root mean square and range of sway for both the anterior-posterior and the medial-lateral directions, and the sway path, were calculated. The nonlinear parameters of approximate entropy, Lyapunov exponent, and correlation dimension for both directions were also calculated. Intrasession and intersession reliability was quantified by the intraclass correlation coefficient (ICC). RESULTS: The nonlinear tool of approximate entropy presented high intrasession and intersession ICC values compared with all other parameters evaluated. Generally, intrasession and intersession reliability increased in the last 2 months of the data collection and as sitting posture matured. CONCLUSIONS: Our results showed that the evaluation of COP data is a reliable method of investigating the development of sitting postural control. The present study emphasizes the need for establishing COP reliability before using it as a method of examining intervention progress directed at improving the sitting postural abilities in infants with motor developmental delays.

Use of information entropy measures of sitting postural sway to quantify developmental delay in infants.

BACKGROUND: By quantifying the information entropy of postural sway data, the complexity of the postural movement of different populations can be assessed, giving insight into pathologic motor control functioning. METHODS: In this study, developmental delay of motor control function in infants was assessed by analysis of sitting postural sway data acquired from force plate center of pressure measurements. Two types of entropy measures were used: symbolic entropy, including a new asymmetric symbolic entropy measure, and approximate entropy, a more widely used entropy measure. For each method of analysis, parameters were adjusted to optimize the separation of the results from the infants with delayed development from infants with typical development. RESULTS: The method that gave the widest separation between the populations was the asymmetric symbolic entropy method, which we developed by modification of the symbolic entropy algorithm. The approximate entropy algorithm also performed well, using parameters optimized for the infant sitting data. The infants with delayed development were found to have less complex patterns of postural sway in the medial-lateral direction, and were found to have different left-right symmetry in their postural sway, as compared to typically developing infants. CONCLUSION: The results of this study indicate that optimization of the entropy algorithm for infant sitting postural sway data can greatly improve the ability to separate the infants with developmental delay from typically developing infants.

Complexity of postural control in infants: linear and nonlinear features revealed by principal component analysis.

Nonlinear analysis of standing postural control in healthy adults reveals a chaotic structure of the center of pressure time series. Independent sitting is the first controlled posture during development, and can also be examined for nonlinear dynamics. We performed a principal component analysis on variables extracted from the center of pressure (COP) time series of infants sitting independently. Our purpose was to describe factors that could be interpreted for clinical use in evaluating postural control for infants, and determine if nonlinear measures provide additional information about postural control not quantified by standard linear measures. Four factors were identified: the area or amount of postural sway and the overall variability of the sway (linear); the complexity of the sway in the anterior-posterior direction (nonlinear); power variability or velocity (linear); and the complexity of the sway in the medial-lateral direction (nonlinear). Nonlinear measures, which are used to examine complexity in many physiological systems, describe the variability of postural control that is not described by linear measures. Nonlinear measures may be critical in determining the developing health of the postural control system in infants, and may be useful in early diagnosis of movement disorders. The measurement of nonlinear dynamics of postural control reveals a chaotic structure of postural control in infancy, which may be an indicator of healthy postural control throughout development.

Nonlinear detrended fluctuation analysis of sitting center-of-pressure data as an early measure of motor development pathology in infants.

Upright sitting is one of the first motor skills an infant learns, and thus sitting postural control provides an early window into the infant's motor development. Early identification of infants with motor developmental delay, such as infants with cerebral palsy, allows for early therapeutic intervention by physical therapists. Early intervention is thought to produce better outcomes, due to greater neural plasticity in younger infants. Postural sway, as measured by a force plate, can be used to objectively and quantitatively characterize infant motor control during sitting. Pathology, such as cerebral palsy, may alter the fractal properties of motor function. Often physiologic time series data, including infant sitting postural sway data, is mathematically non-stationary. Detrended Fluctuation Analysis (DFA) is useful to characterize the fractal nature of time series data because it is does not assume stationarity of the data. In this study we found that suitable selection of the order of the detrending function improves the performance of the DFA algorithm, with a higher order polynomial detrending better able to distinguish infant sitting posture time series data from Brown noise (random walk), and first order detrending better able to distinguish infants with motor delay (cerebral palsy) from infants with typical development.

Water Immersion Affects Episodic Memory and Postural Control in Healthy Older Adults.

BACKGROUND AND PURPOSE: Previous research has reported that younger adults make fewer cognitive errors on an auditory vigilance task while in chest-deep water compared with on land. The purpose of this study was to extend this previous work to include older adults and to examine the effect of environment (water vs land) on linear and nonlinear measures of postural control under single- and dual-task conditions. METHODS: Twenty-one older adult participants (age = 71.6 ± 8.34 years) performed a cognitive (auditory vigilance) and motor (standing balance) task separately and simultaneously on land and in chest-deep water. Listening errors (n = count) from the auditory vigilance test and sample entropy (SampEn), center of pressure area, and velocity for the balance test served as dependent measures. Environment (land vs water) and task (single vs dual) comparisons were made with a Wilcoxon matched-pair test. RESULTS: Listening errors were 111% greater during land than during water environments (single-task = 4.0 ± 3.5 vs 1.9 ± 1.7; P = .03). Conversely, SampEn values were 100% greater during water than during land environments (single-task = 0.04 ± 0.01 vs 0.02 ± 0.01; P < .001). Center of pressure area and velocity followed a similar trend to SampEn with respect to environment differences, and none of the measures were different between single- and dual-task conditions (P > .05). CONCLUSIONS: The findings of this study expand current support for the potential use of partial aquatic immersion as a viable method for challenging both cognitive and motor abilities in older adults.