Balance in children with acute lymphoblastic leukemia.

BACKGROUND: Treatment for acute lymphoblastic leukemia (ALL) can affect balance via different mechanisms, including sensory and motor peripheral neuropathy, cognitive impairment, and reduced muscle strength and flexibility. To provide an overview of what is currently known about the effects of cancer treatment on balance in pediatric ALL patients and survivors, and of the predictors of poor balance, a review of the literature was conducted. METHODS: Five databases were searched for English-language original research articles on balance during or after treatment for pediatric ALL. RESULTS: From a total of nine studies, six identified significant balance problems in children with ALL during or after treatment. The percentage of patients or survivors with impaired balance varied between 27% and 69% during treatment, 7% and 65% a few years after completion of treatment, and 14% and 17% many years after the completion of treatment. Factors associated with impaired balance were higher body mass index; higher intrathecal methotrexate dose; cranial radiation; knee extensor weakness; and impaired cognition. CONCLUSION: Although heterogeneity between the studies regarding patient age; age at diagnosis; time since completion of treatment; and methods of quantifying balance make it difficult to reach a single conclusion, the evidence suggests that survivors may experience short- and/or long-term balance difficulties. While there is a need for additional studies to better understand the effects of impaired balance in survivors, clinicians treating both child and adult survivors of ALL need to be aware of these potential risks.

Applying principles of motor learning and control to upper extremity rehabilitation.

The purpose of this article is to provide a brief review of the principles of motor control and learning. Different models of motor control from historical to contemporary are presented with emphasis on the Systems model. Concepts of motor learning including skill acquisition, measurement of learning, and methods to promote skill acquisition by examining the many facets of practice scheduling and use of feedback are provided. A fictional client case is introduced and threaded throughout the article to facilitate understanding of these concepts and how they can be applied to clinical practice.

The effects of low back pain on natural breath control during a lowering task.

Preventative and rehabilitative efforts relative to low back pain (LBP) and manual material handling (MMH) are often directed toward proper technique. However, breath control may be an additional factor to consider. Optimizing breath control may provide increased segmental control of the spine through the production of increased intra-abdominal pressure. It has been found that breath control differs during the lifting phase of MMH for individuals with LBP. However, little is known about breath control during the lowering portion even though it accounts for 30% of MMH tasks. In this study, individuals with LBP (n = 32) and aged-matched healthy individuals (n = 30) lowered a crate from a table to the floor four times with the crate empty and four times with the crate loaded at 25% of body weight. The amount of volume in the lungs as a percentage of each individual's vital capacity (VC) was identified at nine points during the lowering task. Individuals with LBP completed the lowering task with significantly more volume in their lungs (45.9% VC) than healthy peers (40.9% VC). Further, with increasing age %VC significantly increased in those with LBP. Moreover, %VC significantly increased in response to the mechanical challenges introduced when lowering a load. These findings support the theoretical link between breath control and lumbar segmental control and provide preliminary evidence supporting rehabilitative efforts which add a focus on breath control for those with LBP.

Effects of exercise and B vitamins on homocysteine and glutathione in Parkinson's disease: a randomized trial.

BACKGROUND: Individuals with Parkinson's disease (PD) have decreased glutathione levels and elevated homocysteine levels. These substances are considered markers of health, and an inverse relationship has been suggested through the transsulfuration pathway. This experiment tested the effects of exercise and B vitamin supplementation on homocysteine and glutathione levels, and if a relationship was present between these two markers in those with PD. Secondary aims included examining the impact of the interventions on aerobic efficiency and strength. METHODS: Thirty-six subjects were randomly assigned to 4 groups. The Vit group received vitamins B(6), B(12) and folic acid daily for 6 weeks. The Ex group received aerobic and strength training twice weekly for 6 weeks. The Vit + Ex group received both interventions. A control group received no intervention. Subjects were tested prior to and after intervention on the following measures: glutathione and homocysteine levels, strength measures and oxygen consumption. RESULTS: Subjects who received 6 weeks of B vitamin supplementation had lowered homocysteine levels. Subjects who received 6 weeks of exercise training had increased glutathione levels, strength and aerobic capacity. The combination of vitamin and exercise did not yield greater changes than the separate intervention. The control subjects did not change on any measures. CONCLUSION: Positive results were realized with each intervention; however, the expected relationship between glutathione and homocysteine was not found in this sample of subjects with PD. Homocysteine and glutathione levels can be improved independently in individuals with PD with exercise or vitamins B(6), B(12) and folic acid supplementation.

Individuals with low back pain breathe differently than healthy individuals during a lifting task.

STUDY DESIGN: Case control, repeated-measures, experimental laboratory study. OBJECTIVE: To determine if, during a whole-body lifting task, individuals with low back pain (LBP) breathe differently than age-matched controls. BACKGROUND: Breath control may be optimized to provide increased intersegmental control of the lumbar spine through the generation of intra-abdominal pressure. Consequently, impairments in respiratory and trunk muscle coordination during lifting tasks may contribute to the occurrence or maintenance of LBP. METHODS: Participants without LBP (n = 30) were matched by gender and age with those presenting with chronic mechanical LBP (n = 32) of at least 1 year in duration. Participants completed a total of 8 self-paced lifts of a crate from the floor to a table, with the crate empty during 4 of the lifts and loaded to 25% of the participant's body weight during 4 of the lifts. The amount of volume in the lungs, measured as a percentage of the individual's vital capacity (%VC), was identified at 9 points during the lifting task. A 2 × 2 × 2 × 9 (group by gender by load by time) mixed-model analysis of covariance (ANCOVA), with age as the covariate, was used to identify differences among conditions and groups of %VC used during the lift. RESULTS: Individuals with LBP performed the lifting task with more volume in their lungs (48.2 %VC) than healthy peers (40.9 %VC). Age significantly affected %VC used during the lift: with increasing age, participants with LBP increased inspired volume and participants without LBP decreased inspired volume. CONCLUSIONS: Individuals with LBP performed a lifting task with more inhaled lung volume than individuals without LBP. These findings are consistent with the theoretical link between breath control, intra-abdominal pressure, and lumbar segmental control.

Breath control during manual free-style lifting of a maximally tolerated load.

Clear evidence links voluntary breath control, intra-abdominal pressure and lumbar stability. However, little is known regarding optimal breath control during manual materials handling. No studies have examined natural breath control while lifting a maximal load. Fourteen healthy subjects lifted a loaded crate from the floor to a table while respiratory flow data were collected. The loads lifted began at 10% of body weight and increased up to 50% (if tolerated) by 5% increments. Data from the minimum, moderate and maximum loads were analysed. Uniform and consistent breath holding during lifting of a maximally tolerated load did not occur. Across all three loads, frequency of inspiration was highest immediately prior to lift-off and significantly higher inspired volume occurred at lift-off of the load compared with preparation for lifting. Holding the breath does not appear to be related to lifting of a maximally tolerated load from floor to table. STATEMENT OF RELEVANCE: The findings demonstrate that consistent patterns of naturally occurring breath control during lifting of a maximal load can be identified and do not include uniform breath holding. The findings may assist in creating models for optimal breath control, which will minimise risk of injury during manual material handling tasks.

Norepinephrine and cardiovascular responses to maximal exercise in Parkinson's disease on and off medication.

The aim of this experiment is to understand how Parkinson's disease (PD) medication affects the autonomic responses of individuals during an acute exercise stress test. Fourteen people with PD and fifteen healthy individuals age-matched between 50 and 80 years performed a modified Bruce protocol. Subjects with PD performed the test once off medication (PD-off) and then 1 week later on medication (PD-on). Heart rate (HR), blood pressure (BP), VO(2), and norepinephrine (NE) levels were taken at rest and at peak exercise. At peak exercise HR, BP, and NE values for the PD-on and PD-off group were all significantly lower than healthy controls, regardless of whether subjects were on their medication. Autonomic abnormalities during exercise in this population appear to be disease manifested and not impacted by medications used to treat PD. We can assume, both on and off medication, this population will show markedly lower BP, HR, and NE responses.

The 2- and 8-week effects of decompressive brace use in people with medial compartment knee osteoarthritis.

BACKGROUND: Knee osteoarthritis is a prevalent disease. Unloading the affected compartment using a brace is a treatment option. OBJECTIVES: To determine whether a decompressive knee brace alters loading in medial knee osteoarthritis following 2 and 8 weeks of use. STUDY DESIGN: Within subjects; pre- and post-testing. METHODS: A total of 15 individuals with medial knee osteoarthritis attended four sessions: baseline, fitting, 2 weeks after fitting (post), and 8 weeks after fitting (final). A gait analysis was performed at baseline (without knee brace), post and final. Knee adduction impulse, first and second peak knee adduction moment, knee motion, and walking velocity were calculated. Participants also recorded hours and steps taken while wearing the brace. RESULTS: On average, the brace was worn for more than 6 h/day. Through use of repeated-measures analysis of variance, it was determined that the knee adduction impulse and second peak knee adduction moment were reduced (p < 0.05) at post and final compared to baseline (36% and 34% reduction in knee adduction impulse, 26% reduction in second peak knee adduction moment for post and final, respectively). Furthermore, participants walked faster with increased knee motion during stance. CONCLUSION: The studied decompressive brace was effective in reducing potentially detrimental forces at the knee-knee adduction impulse and second peak knee adduction moment during the stance phase of gait. CLINICAL RELEVANCE: The data from this study suggest that use of a medial unloading brace can reduce potentially detrimental adduction moments at the knee. Clinicians should use this evidence to advocate for use of this noninvasive treatment for people presenting with medial knee osteoarthritis.

Visual properties of objects affect manipulative forces and respiration differently.

Previously, we demonstrated that the respiratory and motor systems responded differently following consecutive lifts of an object whose weight could be altered (lighter or heavier) without changing the object's visual properties. When the weight of the object was altered in a manner unpredictable to the subject, the motor system response reflected the previous weight of the object (light or heavy) while the respiratory system reflected responses seen when lifting the heavier object regardless of whether a lighter or heavier object was lifted previously. It is possible that the default pattern of the respiratory system was due to a lack of visual size cues, which are known to have robust affects on grasp control. To test this hypothesis, 14 seated subjects performed self-initiated alternating lifts with objects whose size and weight covaried such that the weight of the upcoming lift was known despite the weight of the object previously lifted. Following both consecutive and alternating trials, the load force was scaled to the weight of the object (e.g., the heavier the object the larger the force) while the volume was scaled only following the consecutive trials. This suggests that the load forces were developed entirely based on visual information while lung volume was not. In addition, we suggest that following the consecutive trials, the volume increased as the object's weight increased in an effort to assist with trunk stabilization by indirectly increasing intra-abdominal pressure.

Building a framework for a dual task taxonomy.

The study of dual task interference has gained increasing attention in the literature for the past 35 years, with six MEDLINE citations in 1979 growing to 351 citations indexed in 2014 and a peak of 454 cited papers in 2013. Increasingly, researchers are examining dual task cost in individuals with pathology, including those with neurodegenerative diseases. While the influence of these papers has extended from the laboratory to the clinic, the field has evolved without clear definitions of commonly used terms and with extreme variations in experimental procedures. As a result, it is difficult to examine the interference literature as a single body of work. In this paper we present a new taxonomy for classifying cognitive-motor and motor-motor interference within the study of dual task behaviors that connects traditional concepts of learning and principles of motor control with current issues of multitasking analysis. As a first step in the process we provide an operational definition of dual task, distinguishing it from a complex single task. We present this new taxonomy, inclusive of both cognitive and motor modalities, as a working model; one that we hope will generate discussion and create a framework from which one can view previous studies and develop questions of interest.

Internal representations underlying respiration during object manipulation.

We examined the presence of anticipatory control and the resulting interactions of the respiratory and motor systems during discrete object manipulation. In response to an auditory signal, subjects reached forward, grasped, and lifted an instrumented object weighing 150 or 1000 g while the breathing pattern, fingertip forces, and movements were measured. Following every block of five lifts, the object was removed from sight and replaced with the same or an alternate mass. Thus, the object's weight was predictable during the last lift of each block and unpredictable during the first lift after the transition. When the object's weight was predictable, the force application was faster and inspiratory duration and the tidal volume were reduced for the breath associated with the lift for 1000-g compared to 150-g lifts. Following the transition, when the object's weight was unpredictable, the force application reflected the weight of the object during the previous lift while the respiratory output, regardless of the preceding weight, resembled that used for 1000-g lifts. Additionally, inspiratory duration was significantly correlated with the reach duration in three of the four unpredictable lifting conditions. We conclude that these system-specific anticipatory alterations may arise from a common internal representation that was formed through past manipulatory weight experience.

Breath control during a tiptoe task.

Examination of naturally occurring respiration during postural challenges may increase our understanding of the factors linking respiration to lumbar segmental control. This study determined if the timing and magnitude of inhaled volume changes were related to mechanical events that challenge spinal stability during a tiptoe task. Thirty healthy individuals (15 male) had airflow recorded while they completed a tiptoe task which involved: moving onto tiptoe while reaching toward a hanging target (ascent); grasping and holding the target while maintaining the tiptoe position for 3 s (hold); and then returning to the start position (descent). The rate of airflow and amount of inhaled volume (normalized to vital capacity (%VC)) were identified at 13 different intervals spanning the ascent, hold and descent phase. Using repeated measures analysis of variance, significant main effects were identified for both rate of airflow (p < 0.001) and %VC (p < 0.001). Exploration of these main effects revealed that individuals tended to inspire and increase %VC during the ascent phase, hold their breath and maintain %VC during the hold phase when whole body balance is challenged, and exhale during the descent phase. These findings are congruent with theories suggesting that breath control is linked in predictable ways to potentially improve lumbar spine stiffness when presented with mechanical challenges during functional tasks.

Effects of Tyrosine on Parkinson's Disease: A Randomized, Double-Blind, Placebo-Controlled Trial.

Individuals with Parkinson's disease (PD) can suffer from orthostatic hypotension (OH) resulting from reduced levels of norepinephrine (NE), which inhibits the sympathetic nervous system. Levodopa reduces NE levels even further, leading to a greater decrease in blood pressure (BP) and increased OH. Tyrosine is a nonessential amino acid that is the major precursor to NE. Reduced levels of tyrosine have been shown after administration of l-dopa. This study was a single-center, randomized, double-blind, placebo-controlled trial to test the effects of supplementing l-tyrosine on BP, plasma tyrosine, NE levels, and autonomic responses to exercise in PD. Thirty-six subjects with PD receiving l-dopa medication that suffer from OH participated. Random assignment was to a placebo group or l-tyrosine 1,000 mg (500 mg of 2× daily) group for 7 days. OH testing and exercise testing was performed pre- and postsupplementation. There was no effect of tyrosine on BP after OH testing postsupplementation (tyrosine, n = 17; placebo, n = 19). There was an increase in plasma tyrosine in the tyrosine group (P > 0.05). There were no significant changes in any of the secondary outcome measures. l-tyrosine at 1,000 mg (500 mg/2× day) for 7 days is safe and well tolerated in PD. Our results were inconclusive as to whether an increase in plasma tyrosine has an effect on OH in subjects with PD. An increase in plasma tyrosine had no effect on BP or autonomic responses in subjects with PD during acute exercise stress. (Trial registration: http://ClinicalTrials.gov.; identifier: NCT01676103).

Management of proximal femoral focal deficiency with limited resources in Haiti.

BACKGROUND: Individuals with proximal femoral focal deficiency (PFFD) present with a shortened femur. This report highlights the process used to determine prosthetic candidacy, a novel use of the International Committee of the Red Cross (ICRC) prosthetic materials, and subsequent rehabilitation when treating in rural Haiti. CASE DESCRIPTION AND METHODS: An eight-year-old boy with PFFD whose goal was to walk 'normally' presented with a shortened right leg and typical foot/ankle. Concerns regarding ability to safely load the leg were mitigated after finding he could fully load his right limb, control motion, and had no fractures. FINDINGS AND OUTCOMES: A unique prosthosis incorporating a donated hinged ankle-foot orthosis, ICRC materials and a SACH foot was fabricated. Physical therapy followed for two weeks, progressing from static weight-bearing and gait training to dynamic balance activities. At discharge, the patient walked independently using the prosthosis and one forearm crutch. CONCLUSION: Through collaboration and innovation rehabilitation goals can be realized even when presented with limited resources. Clinical relevance Through collaboration and innovation novel prosthetic designs incorporating materials from the International Committee of the Red Cross can be created and rehabilitation goals can be realized even when presented with limited resources.

Cell phones change the way we walk.

Cell phone use among pedestrians leads to increased cognitive distraction, reduced situation awareness and increases in unsafe behavior. Performing a dual-task, such as talking or texting with a cell phone while walking, may interfere with working memory and result in walking errors. At baseline, thirty-three participants visually located a target 8m ahead; then vision was occluded and they were instructed to walk to the remembered target. One week later participants were assigned to either walk, walk while talking on a cell phone, or walk while texting on a cell phone toward the target with vision occluded. Duration and final location of the heel were noted. Linear distance traveled, lateral angular deviation from the start line, and gait velocity were derived. Changes from baseline to testing were analyzed with paired t-tests. Participants engaged in cell phone use presented with significant reductions in gait velocity (texting: 33% reduction, p=0.01; talking: 16% reduction, p=0.02). Moreover, participants who were texting while walking demonstrated a 61% increase in lateral deviation (p=0.04) and 13% increase in linear distance traveled (p=0.03). These results suggest that the dual-task of walking while using a cell phone impacts executive function and working memory and influences gait to such a degree that it may compromise safety. Importantly, comparison of the two cell phone conditions demonstrates texting creates a significantly greater interference effect on walking than talking on a cell phone.

Effects of exercise induced oxidative stress on glutathione levels in Parkinson's disease on and off medication.

Resting plasma glutathione (GSH) levels are lower in individuals with Parkinson's disease (PD) than any other neurological condition. Medications used to treat PD have also been shown to further decrease this depletion. Acute exercise has been shown to be an effective tool to produce oxidative stress in other populations as reflected in lowering levels of GSH. The purpose of this study was to determine how PD responds to acute exercise stress and how medication affects these responses. Fourteen men with PD and 14 men without PD underwent an exercise stress test. Subjects with PD performed the test once off PD medication (PD-Off-med) for 12 h then again 1 week later on PD medication (PD-On-med). GSH and glutathione disulfide (GSSG), were collected via blood draws at rest and after peak exercise along with peak VO(2). At rest and at peak exercise GSH levels and the GSH:GSSG ratio were significantly lower in the PD-On-med and PD-Off-med as compared to controls. GSSG levels were significantly higher in both medication conditions at rest and peak exercise compared to controls. When comparing PD-On-med vs. PD-Off-med at rest and peak exercise, the PD-On-med had lower GSH levels, a lower GSH:GSSG ratio and higher GSSG levels. VO(2) correlated positively with GSH levels. Subjects with PD have lower plasma GSH levels than healthy controls at rest and at peak exercise.

Natural breath control during lifting tasks: effect of load.

Anecdotal evidence suggests that people hold their breath during lifting tasks in order to increase intra-abdominal pressure (IAP) and thereby increase lumbar stability. Studies have shown that voluntary control of the breath influences IAP and that increases in IAP are related to increases in lumbar stability. However, a description of naturally occurring breath control during whole-body lifting tasks in normal healthy subjects is currently not available. Therefore, the specific aims of this study were to: (1) determine the naturally occurring breath patterns during lifting tasks in healthy subjects; (2) determine the effects of different levels of load during lifting tasks on natural breath control patterns in healthy subjects. The present study enrolled 20 healthy subjects to describe inspired volume and categories of airflow direction (inspiration, expiration, or breath hold) during two self-paced lifts of crates loaded at 5, 15, and 25% of body weight. When the breath pattern was examined across all loads there was a significant increase in the magnitude of inspired volume and the frequency of occurrence of inspiration immediately prior to lift-off. When examining the effect of load on breath patterns, there was a significant increase of inspired volume and occurrence of breath holding when lifting the heavy load compared to the medium and light loads. These results suggest that: (1) distinct patterns of natural breath control occur during lifting tasks; and (2) breath control is responsive to the timing and magnitude of load lifted.

Cardiovascular response to treadmill testing in Parkinson disease.

PURPOSE: Exercise has been recommended as a way to maintain quality of life in individuals with Parkinson disease (PD). Experiments examining the cardiovascular response to exercise, however, have yielded controversial results. This study was designed to determine if there is any difference in vital signs and Rate of Perceived Exertion (RPE) between a group of individuals (50-80 years old) with PD and a comparison group of healthy individuals during exercise on a treadmill. METHODS: Twenty seven volunteers (16 with PD and 11 healthy) participated in this study. Subjects with PD were divided into 2 groups; one that reached target heart rate and one that failed to reach it. In this study, heart rate (HR), systolic blood pressure (BP), and the RPE were measured during a Modified Bruce Protocol. We hypothesized that treadmill testing would result in differences between individuals with PD and healthy subjects when HR and systolic BP were compared at submaximal exercise (defined as Stage 2 of the Modified Bruce Protocol) and at peak exercise (defined as 85% of age predicted target heart rate). RESULTS: During submaximal exercise, no significant differences were found between the PD group and the control group for HR, BP, or RPE. At peak exercise, one half of the subjects with PD exhibited blunted cardiovascular responses, despite reaching a comparable intensity of exercise during a Modified Bruce Protocol. CONCLUSIONS: Although cardiovascular responses to exercise on a treadmill appear similar between individuals with PD and controls at lower levels of exercise, half the subjects with PD in the present study displayed abnormal cardiovascular responses at higher exercise intensities. Administering an exercise stress test will illustrate the expected cardiovascular responses for each individual, therefore guiding exercise prescription.