Siri Merete Brændvik

Relationship between neuromuscular body functions and upper extremity activity in children with cerebral palsy.

Aim  Our aim was to investigate the relationship between the dimensions of neuromuscular body function and elbow, forearm, and hand activity in the upper extremities in children/adolescents with spastic cerebral palsy (CP), within the framework of the World Health Organization International Classification of Functioning, Disability and Health.

The role of co-activation in strength and force modulation in the elbow of children with unilateral cerebral palsy

To study the role of coactivation in strength and force modulation in the elbow joint of children and adolescents with cerebral palsy (CP), we investigated the affected and contralateral arm of 21 persons (age 8-18) with spastic unilateral CP in three tasks: maximal voluntary isokinetic concentric contraction and passive isokinetic movement during elbow flexion and extension, and sub-maximal isometric force tracing during elbow flexion. Elbow flexion-extension torque and surface electromyography (EMG) of the biceps brachii (BB) and triceps brachii (TB) muscles were recorded. During the maximal contractions, the affected arm was weaker, had decreased agonist and similar antagonist EMG amplitudes, and thus increased antagonist co-activation (% of maximal activity as agonist) during both elbow flexion and extension, with higher coactivation levels of the TB than the BB. During passive elbow extension, the BB of the affected arm showed increased resistance torque and indication of reflex, and thus spastic, activity. No difference between the two arms was found in the ability to modulate force, despite increased TB coactivation in the affected arm. The results indicate that coactivation plays a minor role in muscle weakness in CP, and does not limit force modulation. Moreover, spasticity seems particularly to increase coactivation in the muscle antagonistic to the spastic one, possibly in order to increase stability.

Effectiveness of resistance training in combination with botulinum toxin-A on hand and arm use in children with cerebral palsy: a pre-post intervention study

BackgroundThe aim of this pilot study was to examine the effects of additional resistance training after use of Botulinum Toxin-A (BoNT-A) on the upper limbs in children with cerebral palsy (CP).MethodsTen children with CP (9–17 years) with unilaterally affected upper limbs according to Manual Ability Classification System II were assigned to two intervention groups. One group received BoNT-A treatment (group B), the other BoNT-A plus eight weeks resistance training (group BT). Hand and arm use were evaluated by means of the Melbourne assessment of unilateral upper limb function (Melbourne) and Assisting Hand Assessment (AHA). Measures of muscle strength, muscle tone, and active range of motion were used to assess neuromuscular body function. Measurements were performed before and two and five months after intervention start. Change scores and differences between the groups in such scores were subjected to Mann–Whitney U and Wilcoxon Signed Rank tests, respectively.ResultsBoth groups had very small improvements in AHA and Melbourne two months after BoNT-A injections, without differences between groups. There were significant, or close to significant, short-term treatment effects in favour of group BT for muscle strength in injected muscles (elbow flexion strength, p = .08) and non-injected muscles (elbow extension and supination strength, both p = .05), without concomitant increases in muscle tone. Active supination range improved in both groups, but more so in group BT (p = .09). There were no differences between the groups five months after intervention start.ConclusionsResistance training strengthens non-injected muscles temporarily and may reduce short-term strength loss that results from BoNT-A injections without increasing muscle tone. Moreover, additional resistance training may increase active range of motion to a greater extent than BoNT-A alone. None of the improvements in neuromuscular impairments further augmented use of the hand and arm. Larger clinical trials are needed to establish whether resistance training can counteract strength loss caused by BoNT-A, whether the combination of BoNT-A and resistance training is superior to BoNT-A or resistance training alone in improving active range of motion, and whether increased task-related training is a more effective approach to improve hand and arm use in children with CP.

The relationship between trunk control in sitting and during gait in children and adolescents with cerebral palsy.

To assess the relationship between trunk control in sitting and trunk control during gait in children and adolescents with cerebral palsy (CP).

European consensus on the concepts and measurement of the pathophysiological neuromuscular responses to passive muscle stretch

To support clinical decision‐making in central neurological disorders, a physical examination is used to assess responses to passive muscle stretch. However, what exactly is being assessed is expressed and interpreted in different ways. A clear diagnostic framework is lacking. Therefore, the aim was to arrive at unambiguous terminology about the concepts and measurement around pathophysiological neuromuscular response to passive muscle stretch.

Gait characteristics in children and adolescents with cerebral palsy assessed with a trunk-worn accelerometer

This study aimed to investigate gait characteristics reflecting balance and progression in children and adolescents with cerebral palsy (CP) compared with typically developing (TD) children. Gait characteristics variables representing aspects of balance were trunk acceleration, interstride regularity and asymmetry of accelerations while gait characteristics representing progression were gait speed, cadence, step time and step length. Children in the age range 5-18 years (mean age 11.1 years) with spastic CP (n=41) and a gross motor function corresponding to GMFCS I-III and children with TD (n=29) were included. The children walked back and forth along a 5m pathway with a tri-axial accelerometer worn on the lower back to allow assessment of their gait characteristics. Data were recorded along the anterioposterior (AP), mediolateral (ML), and vertical (V) axes. To assess the magnitude of potential differences in gait characteristics, standard deviation scores were calculated, using TD children as reference. Gait parameters related to balance, such as AP, ML, and V accelerations, were higher in the children with CP (z-scores between 0.4 and 0.7) and increased with increasing GMFCS levels. The differences in accelerations in the AP and V directions increased between children with CP and TD children with increasing speed. Also asymmetry in trunk accelerations differed significantly between the two groups in all three directions (z-scores between 0.8 and 1.8 higher in the CP group), while interstride regularity differed only slightly between children with CP and TD children, and only in the AP direction. Gait characteristics also differed between children with the spastic subtypes unilateral and bilateral CP, for accelerations and asymmetry in the AP and ML directions. Our results showed significant differences in gait characteristics between children with CP and TD children. The differences may be more related to balance than progression, and these problems seem to rise with increasing gross motor impairment and speed.

Fatigue and muscle activation during submaximal elbow flexion in children with cerebral palsy.

The purpose of this study was to investigate whether children with cerebral palsy (CP), like typically developing peers, would compensate for muscle fatigue by recruiting additional motor units during a sustained low force contraction until task failure. Twelve children with CP and 17 typically developing peers performed one submaximal isometric elbow flexion contraction until the task could no longer be sustained at on average 25% (range 10-35%) of their maximal voluntary torque. Meanwhile surface electromyography (EMG) was measured from the biceps brachii and triceps brachii, and acceleration variations of the forearm were detected by an accelerometer. Slopes of the change in EMG amplitude and median frequency and accelerometer variation during time normalised to their initial values were calculated. Strength and time to task failure were similar in both groups. Children with CP exhibited a lower increase in EMG amplitude of the biceps brachii and triceps brachii during the course of the sustained elbow flexion task, while there were no significant group differences in median frequency decrease or acceleration variation increase. This indicates that children with CP do not compensate muscle fatigue with recruitment of additional motor units during sustained low force contractions.

Treadmill Training or Progressive Strength Training to Improve Walking in People with Multiple Sclerosis? A Randomized Parallel Group Trial

BACKGROUND AND PURPOSE The most effective treatment approach to improve walking in people with multiple sclerosis (MS) is not known. The aim of this trial was to assess the efficacy of treadmill training and progressive strength training on walking in people with MS. METHODS A single blinded randomized parallel group trial was carried out. Eligible participants were adults with MS with Expanded Disability Status Scale score ≤6. A total of 29 participants were randomized and 28 received the allocated exercise intervention, treadmill (n = 13) or strength training (n = 15). Both groups exercised 30 minutes, three times a week for 8 weeks. Primary outcome was The Functional Ambulation Profile evaluated by the GAITRite walkway. Secondary outcomes were walking work economy and balance control during walking, measured by a small lightweight accelerometer connected to the lower back. Testing was performed at baseline and the subsequent week after completion of training. RESULTS Two participants were lost to follow-up, and 11 (treadmill) and 15 (strength training) were left for analysis. The treadmill group increased their Functional Ambulation Profile score significantly compared with the strength training group (p = .037). A significant improvement in walking work economy (p = .024) and a reduction of root mean square of vertical acceleration (p = .047) also favoured the treadmill group. DISCUSSION The results indicate that task-specific training by treadmill walking is a favourable approach compared with strength training to improve walking in persons with mild and moderate MS. Implications for Physiotherapy practice, this study adds knowledge for the decision of optimal treatment approaches in people with MS. Copyright

Lower limb muscle fatigue during walking in children with cerebral palsy

To investigate whether more prominent signs of muscle fatigue occur during self‐paced walking in children with cerebral palsy (CP) compared to typically developing peers.

Ventilatory efficiency and aerobic capacity in people with multiple sclerosis: A randomized study

Objectives: To assess ventilatory efficiency and aerobic capacity in people with multiple sclerosis and whether treadmill walking or progressive strength training has an effect on these parameters in this population. Methods: In all, 24 adults with multiple sclerosis with an Expanded Disability Status Scale score of ≤6 completed a cardiopulmonary exercise test before and after 8 weeks of exercise. They were randomized to treadmill walking of low-to-moderate intensity (50%–70% of peak heart rate) or progressive strength training (six repetitions × two at 80% of one repetition maximum). Both groups exercised for 30 min three times per week. Primary outcome measure was ventilatory efficiency measured as the minute ventilation/carbon dioxide production (VE/VCO2) ratio and oxygen uptake efficiency slope. Secondary outcome was aerobic capacity, measured as peak oxygen uptake (VO2peak). Results: Despite low aerobic capacity, ventilatory efficiency was found to be within normal range. After 8 weeks of exercise, no significant between-group differences emerged in (1) VE/VCO2 ratio (26 ± 2.2 to 26 ± 2.0, 29 ± 2.0 to 28 ± 2.3, p = 0.66), (2) oxygen uptake efficiency slope (2697 ± 442 to 2701 ± 577, 2473 ± 800 to 2481 ± 896, p = 0.71), or (3) VO2peak in mL/kg/min (28 ± 4.4 to 30 ± 4.3, 29 ± 6.7 to 29 ± 6.4, p = 0.38) in treadmill walking and progressive strength training, respectively. There were no significant within-group differences either. No adverse events occurred during cardiopulmonary exercise test or exercise training. Conclusion: In people with mild-to-moderate multiple sclerosis, 8 weeks of treadmill walking of low-to-moderate intensity or progressive strength training did not have any effect on ventilatory efficiency or aerobic capacity. Although aerobic capacity was lower than reference values, ventilatory efficiency was not reduced.