Hans Bussmann

Detection of static and dynamic activities using uniaxial accelerometers

Rehabilitation treatment may be improved by objective analysis of activities of daily living. For this reason, the feasibility of distinguishing several static and dynamic activities (standing, sitting, lying, walking, ascending stairs, descending stairs, cycling) using a small set of two or three uniaxial accelerometers signals can be measured with a portable data acquisition system, which potentially makes it possible to perform online detection of static and dynamic activities in the home environment. However, the procedures described in this paper have yet to be evaluated in the home environment. Experiments were conducted on ten healthy subjects, with accelerometers mounted on several positions and orientations on the body, performing static and dynamic activities according to a fixed protocol. Specifically, accelerometers on the sternum and thigh were evaluated. These accelerometers were oriented in the sagittal plane, perpendicular to the long axis of the segment (tangential), or along this axis (radial). First, discrimination between the static or dynamic character of activities was investigated. This appeared to be feasible using an rms-detector applied on the signal of one sensor tangentially mounted on the thigh. Second, the distinction between static activities was investigated. Standing, sitting, lying supine, on a side and prone could be distinguished by observing the static signals of two accelerometers, one mounted tangentially on the thigh, and the second mounted radially on the sternum. Third, the distinction between the cyclical dynamic activities walking, stair ascent, stair descent and cycling was investigated. The discriminating potentials of several features of the accelerometer signals were assessed: the mean value, the standard deviation, the cycle time and the morphology. Signal morphology was expressed by the maximal cross-correlation coefficients with template signals for the different dynamic activities. The mean signal values and signal morphology of accelerometers mounted tangentially on the thigh and the sternum appeared to contribute to the discrimination of dynamic activities with varying detection performances. The standard deviation of the signal and the cycle time were primarily related to the speed of the dynamic activities, and did not contribute to the discrimination of the activities. Therefore, discrimination of dynamic activities on the basis of the combined evaluation of the mean signal value and signal morphology is proposed.

Barriers to and facilitators of everyday physical activity in persons with a spinal cord injury after discharge from the rehabilitation centre

OBJECTIVE To determine the most important barriers to and facilitators of the level of everyday physical activity in persons with a spinal cord injury after discharge from the rehabilitation centre. DESIGN Qualitative study with both cross-sectional and retrospective questions. SUBJECTS Thirty-two persons with a spinal cord injury. METHODS Semi-structured interview with questions concerning the current situation (>9 months after discharge) and retrospective questions concerning the period shortly after discharge (=3 months). The interview consisted of 10 topic categories assumed to have an impact on the level of everyday physical activity and covering the main parts of the International Classification of Functioning, Disability and Health (ICF) model. RESULTS In the current situation, the most important barriers were problems with accessibility of stores and buildings, physical health problems and mental health problems. Shortly after discharge, the most important barriers were emotional distress, problems with self-care, and mental health problems. The most frequently mentioned facilitators were preparation in the rehabilitation centre with respect to daily activities and social activities and stimulation to be physically active. CONCLUSION Persons with a spinal cord injury experience important barriers to physical activity, particularly on the ICF component Body Functions and Structure.

Does aerobic training lead to a more active lifestyle and improved quality of life in patients with chronic heart failure

Due to dyspnea and fatigue, patients with chronic heart failure (CHF) are often restricted in the performance of everyday activities, which gradually may lead to hypoactivity.

VALIDITY OF AMBULATORY ACCELEROMETRY TO QUANTIFY PHYSICAL ACTIVITY IN HEART FAILURE

The purpose was to assess the validity of a novel Activity Monitor to quantify physical activity in congestive heart failure. The Activity Monitor is based on long-term ambulatory monitoring of signals from body-fixed accelerometers. Information can be obtained on which mobility-related activity is performed, when, how intense, and for how long. Ten patients performed several functional activities. Continuous registrations of accelerometer signals were made and the output was compared with visual analysis of simultaneously made video recordings (reference method). Overall results showed an agreement between both methods of 90%. Percentages of sensitivity and predictive value were higher than 80% for most activities. Overall number of transitions was determined well (Activity Monitor, 153; video, 149; p = 0.33). It was concluded that the Activity Monitor is a valid instrument to quantify several aspects of everyday physical activity in congestive heart failure.

Evidence of a logarithmic relationship between motor capacity and actual performance in daily life of the paretic arm following stroke

OBJECTIVE To examine the associations between actual performance in daily life and function, capacity and self-perceived performance of the paretic upper limb following stroke. POPULATION Seventeen individuals with stroke. OUTCOME MEASURES Correlation coefficients between actual performance (measured with the Stroke-Upper Limb Activity Monitor), function (Fugl-Meyer Assessment), capacity (Action Research Arm test) and self-perceived performance (ABILHAND questionnaire). RESULTS High correlations were found between actual performance and function (r = 0.75; 95% confidence interval (CI): 0.42-0.90), and capacity (r =0.71; 95% CI: 0.35-0.89), whereas a moderate correlation was found between actual performance and self-perceived performance (r = 0.64; 95% CI: 0.21-0.86). For the relationship between actual performance and both function and capacity, logarithmic regression explained more variance than did linear regression. CONCLUSION The present study provides first evidence of the existence of a non-linear relationship between actual performance, function and capacity of the paretic upper limb following stroke. The results indicate that function and capacity need to reach a certain threshold-level before actual performance also starts to increase. Because of the small sample size of the present study caution is needed when generalizing these results.

Analysing the favourable effects of physical exercise: Relationships between physical fitness, fatigue and functioning in Guillain-Barré syndrome and chronic inflammatory demyelinating polyneuropathy

OBJECTIVE To elucidate the effects of physical exercise in severely fatigued patients with Guillain-Barré syndrome and chronic inflammatory demyelinating polyneuropathy, and to clarify the mutual relationships between 5 domains studied in these patients: physical fitness, fatigue, objectively measured actual mobility, perceived physical functioning, and perceived mental functioning. DESIGN Case series. SUBJECTS/PATIENTS Twenty patients with Guillain-Barré syndrome and chronic inflammatory demyelinating polyneuropathy. METHODS The patients undertook a 12-week physical exercise program. Relationships between domains were studied in the change scores, and additionally in the baseline data of patients. The percentage of significant relationships between each pair of domains was determined. RESULTS In the change scores, a small percentage of significant relationships was found between the physical fitness domain and the other 4 domains (2/30, 7%). A higher percentage of significant relationships was found between the domains perceived mental functioning and actual mobility (44%), perceived mental functioning and perceived physical functioning (44%), and between fatigue and perceived physical functioning (33%). Generally, similar patterns were found in the baseline data. CONCLUSION Changes in fatigue, actual mobility and perceived functioning seem not to be influenced by changes in physical fitness. This study stresses the presence and importance of additional effects of a physical training program, not directly related to increasing fitness.

Physical fitness and physical activity in fatigued and non-fatigued inflammatory bowel disease patients

Abstract Objective. To assess physical fitness and physical activity in inflammatory bowel disease (IBD) patients and whether fatigue is associated with impaired physical fitness and impaired physical activity. Materials and methods. Ten patients with quiescent IBD and fatigue (fatigue group [FG]) based on the Checklist Individual Strength-Fatigue score of ≥35 were matched for age (±5 years) and sex with a non-fatigue group (NFG) with IBD. Physical fitness was measured with a cyclo-ergometric-based maximal exercise test, a submaximal 6-min walk test, and a dynamometer test to quantify the isokinetic muscle strength of the knee extensors and flexors. Level of physical activity was measured with an accelerometer-based activity monitor. Results. The patients in both groups did not differ in regard to medication use, clinical characteristics, and body composition. However, medium-to-large effect sizes for impaired physical fitness (both cardiorespiratory fitness and muscle strength) and physical activity were seen between the patients in the FG and the NFG. Especially, intensity of physical activity was significantly lower in the FG patients compared with the NFG patients (effect size: 1.02; p = 0.037). Similar results were seen when outcomes of the FG and NFG were compared with reference values of the normal population. Conclusion. Fatigued IBD patients show an impaired physical fitness and physical activity compared with non-fatigued IBD patients. This gives directions for a physical component in fatigue in IBD patients. Therefore, these new insights into fatigue indicate that these patients might benefit from an exercise program to improve physical fitness and physical activity.

Effects of Naratriptan Versus Naproxen on Daily Functioning in the Acute Treatment of Migraine: A Randomized, Double-Blind, Double-Dummy, Crossover Study

Objective.—To evaluate the effect of acute treatment on ictal behavioral functioning of patients with migraine via ambulatory accelerometry.

Low-Intensity Wheelchair Training in Inactive People with Long-Term Spinal Cord Injury: A Randomized Controlled Trial on Fitness, Wheelchair Skill Performance and Physical Activity Levels

OBJECTIVE To investigate the effects of low-intensity wheelchair training on wheelchair-specific fitness, wheelchair skill performance and physical activity levels in inactive people with long-term spinal cord injury. DESIGN Randomized controlled trial. PARTICIPANTS Inactive manual wheelchair users with spinal cord injury for at least 10 years (n = 29), allocated to exercise (n = 14) or no exercise. METHODS The 16-week training consisted of wheelchair treadmill-propulsion at 30-40% heart rate reserve or equi-valent in terms of rate of perceived exertion, twice a week, for 30 min per session. Wheelchair-specific fitness was determined as the highest 5-s power output over 15-m overground wheelchair sprinting (P5-15m), isometric push-force, submaximal fitness and peak aerobic work capacity. Skill was determined as performance time, ability and strain scores over a wheelchair circuit. Activity was determined using a questionnaire and an odometer. RESULTS Significant training effects appeared only in P5-15m (exercise vs control: mean +2.0 W vs -0.7 W, p = 0.017, ru=0.65). CONCLUSION The low-intensity wheelchair training appeared insufficient for substantial effects in the sample of inactive people with long-term spinal cord injury, presumably in part owing to a too-low exercise frequency. Effective yet feasible and sustainable training, as well as other physical activity programmes remain to be developed for inactive people with long-term spinal cord injury.