Leo A. van Eykern

Development of postural adjustments during reaching in sitting children

We evaluated the development of postural adjustments accompanying reaching movements in sitting children. Twenty-nine typically developing children aged, 2–11 years, and ten adults were studied with multiple surface electromyograms (EMGs) and kinematics during reaching in four conditions: sitting with the seat-surface oriented horizontally with and without an additional task load, and sitting with the seat-surface tilted 15° forward and 15° backward. The development of postural adjustments during reaching in a sitting position turned out to have a non-linear and protracted course, which is not finished by the age of 11 years. The development of these adjustments is characterised by variation, yet specific developmental sequences could be distinguished. Firstly, the development of postural adjustments during reaching from the age of 2 years onwards lacked a preference for an en bloc strategy, which consists of an in concert activation of the direction-specific neck and trunk muscles. Secondly, anticipatory postural muscle activity, which was consistently present in adults, was virtually absent between 2 and 11 years of age. Thirdly, the data demonstrated that with increasing age the head gradually becomes the dominant frame of reference. In addition, the study suggested that, in terms of postural control, the forward-tilted position is the most efficient one.

Effect of Seat Surface Inclination on Postural Control During Reaching in Preterm Children With Cerebral Palsy

Background and Purpose Because it is debatable whether seat surface inclination improves motor function in children with cerebral palsy (CP), the effect of seat surface tilting on postural control and quality of reaching was studied. Subjects The subjects were 58 children with CP aged 2 to 11 years (34 with unilateral spastic CP, 24 with bilateral spastic CP). Methods During the task of reaching movements, surface electromyographic and kinematic data were recorded for posture and reaching with the dominant arm in 3 sitting conditions: horizontal seat surface, seat surface tilted forward 15 degrees, and seat surface tilted backward 15 degrees. Results In the children with unilateral spastic CP, forward tilting improved postural efficiency and quality of reaching. In the children with bilateral spastic CP, both forward and backward tilting of the seat surface was associated with more postural instability and did not affect the quality of reaching. Discussion and Conclusion The results suggest that, in terms of postural control and quality of reaching, children with unilateral spastic CP benefit from a forward-tilted position and children with bilateral spastic CP benefit from a horizontal sitting position.

Amplitude-integrated electroencephalographic activity is suppressed in preterm infants with high scores on illness severity

BACKGROUND The neonatal acute physiology score, SNAP-II, reflects the severity of illness in newborns. In term newborns, amplitude integrated EEG (aEEG), is depressed following asphyxia. In preterm infants aEEG is discontinuous, and therefore more difficult to assess compared to term infants. AIMS Our first aim was to investigate whether assessing aEEG amplitudes by calculating amplitude centiles was consistent with assessment by pattern recognition. Our second aim was to investigate whether the aEEGs of preterm infants were influenced by SNAP-II. STUDY DESIGN AND SUBJECTS We recorded aEEGs in 38 infants with a mean gestational age of 29.7 weeks (26.0-31.8 weeks) during the first five days of life. The mean recording time was 130 min. The aEEGs were assessed by pattern recognition, by calculating Burdjalov score, and by calculating the mean values of the 5th, 50th, and 95th centiles of the aEEG amplitudes. Illness severity was determined within the first 24h. RESULTS We assessed 151 recordings and found strong correlations between the 5th and 50th amplitude centiles and the Burdjalov scores (r=0.71, p<0.001 and r=0.47, p<0.001, respectively). The 5th and 50th amplitude centiles correlated with SNAP-II (r=-0.34, p<0.0001 and r=-0.27, p=0.001). These correlations were the strongest on the first day of life (r=-0.55, p=0.005 and r=-0.47, p=0.018, respectively). The 5th and the 50th amplitude centiles were best predicted by gestational age, SNAP-II, and low blood pressure. CONCLUSIONS Severe illness as measured by the SNAP-II, and low blood pressure had a negative influence on the aEEGs of preterm infants.

Airflow limitation in asthmatic children assessed with a non-invasive EMG technique

The aim of the study was to investigate the association between electromyography (EMG) of the diaphragm and intercostal muscles and the forced expiratory volume in 1 s (FEV(1)) at different levels of histamine-induced airflow limitation, and the response to salbutamol. Moreover, we assessed the reproducibility of the EMG measurements on 2 different occasions during different levels of airflow limitation in asthmatic school children. Fourteen children with asthma performed 2 histamine challenges with a 24-h time interval and 1 child performed 1 histamine challenge. The EMG signals were derived from surface electrodes. The logarithm of the EMG-activity-ratio (log EMGAR; mean peak-bottom ratio of respiratory muscle activity) was used as EMG parameter. The log EMGAR of the diaphragm (di) and the log EMGAR of the intercostal muscles (int) associated well with the histamine-induced fall in FEV(1) at 5% steps from the baseline value. After administration of salbutamol log EMGARdi and log EMGARint returned to baseline mean peak-bottom values (for all leads P<0.001). The EMGARdi and EMGARint values were reproducible at different levels of airflow limitation. This study showed that EMGARdi and EMGARint as a parameter for a change in electrical activity of the diaphragm and intercostal muscles associated well with FEV(1), was reversible after salbutamol and was reproducible at different levels of histamine-induced airflow limitation in asthmatic school children.

Electromyographic monitoring of respiratory muscle activity in dyspneic infants and toddlers

The aim of this study was to investigate whether the changes that occurred in the clinical asthma score (CAS) correlated with the changes in the respiratory electromyographic (EMG) activity over the days during admission to hospital in dyspneic infants and toddlers. Sixteen infants and toddlers (9 males) were studied during admission and 7 days after discharge. The CAS was used to assess the severity of dyspnea and consists of five items: respiration rate, wheezing, retractions, observed dyspnea, and inspiration-to-expiration ratio. Each item was scaled 0, 1, or 2, with a maximum score of 10. Electrical activity from the diaphragm (di) and intercostal muscles (int) was derived from surface electrodes. The logarithm of the EMG-Activity-Ratio (log EMGAR; ratio of mean peak-to-bottom EMG activity during admission to the hospital, to that at baseline, 7 days after discharge) was used as EMG parameter. For assessing the association between the repeated observations of the CAS and the EMG measurements we used the quantity r2 obtained with analysis of covariance. On the day of admission the patients had a mean CAS of 5.9 +/- 1.2. On the day of discharge the mean CAS decreased significantly to 2.1 +/- 1.6, indicating that the CAS returned to normal values. In line with this observation, a significant decrease in the log EMGARdi and log EMGARint was observed during the stay in the hospital. Over all subjects the correlation coefficient (r) of log EMGARdi versus CAS was 0.71, log EMGARint versus CAS was 0.67, and the mean log EMGAR versus CAS was 0.75 (p < 0.01, for all values). The correlation coefficients of subjects of < or = 1 year seemed to be lower than those of subjects of > 1 year of age (p < 0.01) and female subjects showed higher correlation coefficients than males. This study showed a moderate, but significant, relationship between the changes that occurred in the CAS and the changes in respiratory EMG activity during admission to hospital in dyspneic infants and toddlers. Moreover, the correlation coefficients of the combined leads of the intercostals and diaphragm (mean log EMGAR) were higher than those of the separate leads. The EMG measurements would extend diagnostic possibilities and would provide an objective measure to evaluate the clinical course of the disease and the efficacy of therapy in infants and toddlers with recurrent wheezing disorders.

Observation of movements during sleep in ALTE (apparent life threatening event) and apnoeic infants- a pilot study

Fourteen infants of 2 months or 6 months of age were video-recorded during polysomnography. Four were normal infants, five had a history of ALTE (apparent life threatening event) and five had repeated and prolonged apnoea during sleep. Two ALTE infants have been recorded at 2 months as well as at 6 months of age. Movements during sleep could be classified into general movements, isolated movements of the upper extremity, startles, head rotations, and trunk rotations. In the ALTE cases at 2 months of age, the motility was quantitatively not different from the control infants but was markedly reduced at 6 months of age. (All cases had their event before 8 weeks of age.) In contrast to these findings, infants with repeated apnoea did not show a clear change in the quantity of their movements. With the exception of one ALTE case at 2 months, all observed cases of ALTE and apnoeic infants showed an abnormal quality of their spontaneous movements during sleep. As reported in a previous study, all these cases had also been found moving abnormally during wakefulness. It is suggested that the abnormal motility is a sequelae of the event (ALTE or repeated apnoeas) with as a consequence, an impairment of neural functions.

Development of proximal arm muscle control during reaching in young infants: from variation to selection.

UNLABELLED Reaching movements are initiated by activity of the prime mover, i.e. the first activated arm muscle. We aimed to investigate the relationship between prime mover activity and kinematics of reaching in typically developing (TD) infants in supine and sitting position. Fourteen infants were assessed at 4 and 6 months during reaching in supine and supported sitting. Kinematics and EMG-activity of deltoid, pectoralis major, biceps (BB) and triceps brachii were recorded. Kinematic analysis focused on number of movement units (MUs) and transport MU (MU with longest duration). Prime mover use was variable, but at 6 months a dominance of BB emerged in both testing conditions. Kinematics were also variable, but with increasing age the number of MU decreased and the relative proportion of the transport MU increased. BB as prime mover at 6 months was related to a larger transport MU. CONCLUSION Between 4 and 6 months BB prime mover dominance emerges which is related to relatively efficient reaching characteristics.

Respiratory Muscle Activity Related to Flow and Lung Volume in Preterm Infants Compared With Term Infants

Infants with chronic lung disease (CLD) have a capacity to maintain functional lung volume despite alterations to their lung mechanics. We hypothesize that they achieve this by altering breathing patterns and dynamic elevation of lung volume, leading to differences in the relationship between respiratory muscle activity, flow and lung volume. Lung function and transcutaneous electromyography of the respiratory muscles (rEMG) were measured in 20 infants with CLD and in 39 healthy age-matched controls during quiet sleep. We compared coefficient of variations (CVs) of rEMG and the temporal relationship of rEMG variables, to flow and lung volume [functional residual capacity (FRC)] between these groups. The time between the start of inspiratory muscle activity and the resulting flow (tria)—in relation to respiratory cycle time—was significantly longer in infants with CLD. Although FRC had similar associations with tria and postinspiratory activity (corrected for respiratory cycle time), the CV of the diaphragmatic rEMG was lower in CLD infants (22.6 versus 31.0%, p = 0.030). The temporal relationship of rEMG to flow and FRC and the loss of adaptive variability provide additional information on coping mechanisms in infants with CLD. This technique could be used for noninvasive bedside monitoring of CLD.

Respiratory muscle activity and patient–ventilator asynchrony during different settings of noninvasive ventilation in stable hypercapnic COPD: does high inspiratory pressure lead to respiratory muscle unloading?

Introduction High-intensity noninvasive ventilation (NIV) has been shown to improve outcomes in stable chronic obstructive pulmonary disease patients. However, there is insufficient knowledge about whether with this more controlled ventilatory mode optimal respiratory muscle unloading is provided without an increase in patient–ventilator asynchrony (PVA). Patients and methods Ten chronic obstructive pulmonary disease patients on home mechanical ventilation were included. Four different ventilatory settings were investigated in each patient in random order, each for 15 min, varying the inspiratory positive airway pressure and backup breathing frequency. With surface electromyography (EMG), activities of the intercostal muscles, diaphragm, and scalene muscles were determined. Furthermore, pressure tracings were derived simultaneously in order to assess PVA. Results Compared to spontaneous breathing, the most pronounced decrease in EMG activity was achieved with the high-pressure settings. Adding a high breathing frequency did reduce EMG activity per breath, while the decrease in EMG activity over 1 min was comparable with the high-pressure, low-frequency setting. With high backup breathing frequencies less breaths were pressure supported (25% vs 97%). PVAs occurred more frequently with the low-frequency settings (P=0.017). Conclusion High-intensity NIV might provide optimal unloading of respiratory muscles, without undue increases in PVA.

Does surgical management of the hand in children with unilateral spastic cerebral palsy affect muscle coordination and quality of reaching

Judith C van Munster MD, Carel GB Maathuis MD PHD, Nienke Haga MD, Leo A Van Eykern, Mijna Hadders-Algra MD PHD 1 Center for Rehabilitation, University Medical Center Groningen (UMCG) Groningen, the Netherlands. 2 Rehabilitation Centre Revalidatie Friesland, Beetsterzwaag, the Netherlands. 3 Department of Paediatrics – Developmental Neurology, UMCG, Groningen, the Netherlands. Correspondence to: j.vanmunster@maartenskliniek.nl