Diane L. Damiano

A report: the definition and classification of cerebral palsy April 2006.

For a variety of reasons, the definition and the clawification of cerebral palsy (CP) need to be reconsidered. Modern brain imaging techniques have shed new light on the nature of the underlying brain injury and studies on the neurobiology of and pathology associated with brain development have further explored etiologic mechanisms. It is now recognized that assessing the extent of activity restriction is part of CP evaluation and that people without activity restriction should not be included in the CP rubric. Also, previous definitions have not given sufficient prominence to the non‐motor neurodevelopmental disabilities of performance and behaviour that commonly accompany CP, nor to the progression of musculoskeletal difficulties that often occurs with advancing age. In order to explore this information, pertinent material was reviewed on July 11–13,2004 at an international workshop in Bethesda, MD (USA) organized by an Executive Committee and participated in by selected leaders in the preclinical and clinical sciences. At the workshop, it was agreed that the concept ‘cerebral palsy’ should be retained. Suggestions were made about the content of a revised definition and classification of CP that would meet the needs of clinicians, investigators, health officials, families and the public and would provide a common language for improved communication. Panels organized by the Executive Committee used this information and additional comments from the international community to generate a report on the Definition and Classification of Cerebral Palsy, April 2006. The Executive Committee presents this report with the intent of providing a common conceptualization of CP for use by a broad international audience.

Proposed definition and classification of cerebral palsy, April 2005

Because of the availability of new knowledge about the neurobiology of developmental brain injury, information that epidemiology and modern brain imaging is providing, the availability of more precise measuring instruments of patient performance, and the increase in studies evaluating the efficacy of therapy for the consequences of injury, the need for reconsideration of the definition and classification of cerebral palsy (CP) has become evident. Pertinent material was reviewed at an international symposium participated in by selected leaders in the preclinical and clinical sciences. Suggestions were made about the content of a revised definition and classification of CP that would meet the needs of clinicians, investigators, and health officials, and provide a common language for improved communication. With leadership and direction from an Executive Committee, panels utilized this information and have generated a revised Definition and Classification of Cerebral Palsy. The Executive Committee presents this revision and welcomes substantive comments about it.

Functional outcomes of strength training in spastic cerebral palsy

OBJECTIVE To determine clinical effectiveness of strength training in children with spastic cerebral palsy. DESIGN Prospective before and after trial in which subjects participated in a 6-week strength training program. All received before and after isometric strength evaluation of eight muscle groups in both lower extremities with a hand-held dynamometer, 3-D gait analysis at free and fast speeds, administration of the Gross Motor Function Measure (GMFM), and assessment of energy expenditure during gait. SETTING Pediatric rehabilitation center at a tertiary care hospital. PATIENTS Eleven children met inclusion criteria for participation. Six had spastic diplegia, were limited community ambulators, and demonstrated less than 50% of normal muscle strength. Five had spastic hemiplegia and demonstrated a 20% strength asymmetry in at least two muscles across extremities. RESULTS Each group had significant strength gains in the muscles targeted. The entire cohort had higher gait velocity primarily as a result of increased cadence, with greater capacity to walk faster. GMFM Dimension 5 also improved, with no change in energy expenditure. Asymmetry in strength improved in hemiplegia, with no change in asymmetry in support times or joint motion across extremities. CONCLUSIONS This study reinforced the relationship of strength to motor function in cerebral palsy and further demonstrated the effectiveness of strengthening in this population.

Lower-Extremity strength profiles in spastic cerebral palsy

Although weakness has been identified in cerebral palsy (CP) in isolated muscle groups, the magnitude of weakness in multiple muscles and the patterns of weakness across joints have not been documented. The maximum voluntary contraction of eight muscle groups in the lower extremities of 15 children with spastic diplegia, 15 with spastic hemiplegia, and 16 age‐matched peers was determined using a hand‐held dynamometer. Children with spastic diplegia were shown to be weaker than age‐matched peers in all muscles tested, as were the children with hemiplegia on the involved side, with strength differences also noted on the uninvolved side. Weakness was more pronounced distally in the groups with CP, and the hip flexors and ankle plantarflexors in spastic CP tended to be relatively stronger than their antagonists as compared with the strength ratios of the comparison group. In conclusion, children with spastic CP demonstrate quantifiable lower‐extremity weakness and muscle imbalance across joints.

Muscle response to heavy resistance exercise in children with spastic cerebral palsy

Fourteen ambulatory children with spastic diplegia participated in a bilateral quadriceps. strengthening program in an attempt to decrease the amount of knee crouch during gait. Each chid exercised three times a week for six weeks using free ankle weights at a load of 65 per cent of maximum. A normal comparison group of 25 children was also tested under identical conditions. Children with cerebral palsy were significantly weaker in the quadriceps and hamstrings muscle groups than controls. Quadriceps strength increased signficantly at all three angles of knee flexion as a result of the weight‐training program and did not differ statistically from normal at the end of the program. Quadriceps weakness was shown to be a factor in crouch gait; restoring strength through resistance exercise may be a useful adjunct in the treatment of cerebral palsy.

The evolution of gait in childhood and adolescent cerebral palsy.

A longitudinal study over a mean of 32 months was conducted on 18 subjects with spastic diplegia, ranging in age from 4 to 14 years. Three-dimensional gait analyses were performed to compare the temporal and kinematic data across the two time intervals. The comparison revealed a deterioration of gait stability evidenced by increases in double support and decreases in single support with time and growth (p < 0.05). Kinematic analysis revealed a loss of excursion about the knee, ankle, and pelvis (p < 0.05). Additionally, passive range-of-motion analysis revealed a decrease in the popliteal angle over time (p < 0.05). In conclusion, this longitudinal investigation revealed that, in contrast to the gait of children with intact motor function, ambulatory ability tends to worsen over time in spastic cerebral palsy. Insight into the natural progression of gait function in cerebral palsy is essential when evaluating the change in motor status over time or the effects of an intervention in this population.

Promotion of Physical Fitness and Prevention of Secondary Conditions for Children With Cerebral Palsy: Section on Pediatrics Research Summit Proceedings

Inadequate physical fitness is a major problem affecting the function and health of children with cerebral palsy (CP). Lack of optimal physical activity may contribute to the development of secondary conditions associated with CP such as chronic pain, fatigue, and osteoporosis. The purpose of this article is to highlight the content and recommendations of a Pediatrics Research Summit developed to foster collaborative research in this area. Two components of physical fitness—muscle strength and cardiorespiratory fitness—were emphasized. Although there is evidence to support the use of physical fitness interventions, there are many gaps in our current knowledge. Additional research of higher quality and rigor is needed in order to make definitive recommendations regarding the mode, intensity, frequency, and duration of exercise. Outcome measurements have focused on the body functions and structures level of the International Classification of Functioning, Disability and Health (ICF), and much less is known about effects at the activities and participation levels. Additionally, the influence of nutritional and growth factors on physical fitness has not been studied in this population, in which poor growth and skeletal fragility have been identified as serious health issues. Current intervention protocols and outcome measurements were critically evaluated, and recommendations were made for future research.

What does the Ashworth scale really measure and are instrumented measures more valid and precise

This study aimed to explore the limitations of the Ashworth scale for measuring spasticity. An isokinetic dynamometer to quantify resistance to passive stretch and surface EMG was used to verify if a stretch response occurred and, if so, at what joint angle. The authors sought to determine which components of passive resistance (magnitude, rate of change, onset angle of stretch, or velocity dependence) were most related to Ashworth scores and which were related to motor function in cerebral palsy (CP). Twenty-two individuals with spastic CP (11 males, 11 females; mean age 11.9 years, SD 4.3) and a comparison group of nine children without CP (four males, five females; mean age 11.3 years, SD 2.5) participated in the study. The group with CP included those with a diagnosis of spastic diplegia, hemiplegia, or quadriplegia, distributed across Gross Motor Functional Classification Levels. Procedures included: (1) clinical assessment at the knee joint, (2) functional assessments, and (3) isokinetic assessment of passive resistance torque in hamstrings and quadriceps at three velocities. EMG data were recorded simultaneously to identify stretch responses. Detecting stretch responses using the Ashworth scale compared with instrumented measures showed near complete agreement at extremes of the scale, with marked inconsistencies in mid-range values. Ashworth scores were correlated with instrumented measures, particularly for the quadriceps, with higher correlations to the rate of change in resistance (stiffness) and onset angle of stretch than to peak resistance torque. Those with greater resistance tended to have poorer function with isokinetic relations typically stronger.

Spasticity versus strength in cerebral palsy: relationships among involuntary resistance, voluntary torque, and motor function.

Despite the lack of consensus of the role of spasticity in the observed motor disability in cerebral palsy (CP), alleviation of spasticity remains a primary focus in the clinical management of these patients. The purposes of this study were to: (1) quantify voluntary torque and passive resistance across speeds in the hamstrings and quadriceps muscle groups with respect to the presence of stretch responses and/or passive muscle stiffness in patients with CP compared to age‐related children without disability, and (2) relate these parameters to each other and to functional performance, as measured by the Gross Motor Function Measure (GMFM), in CP. Included were 23 subjects with CP, sub‐grouped by the presence or absence of stretch responses as determined by electromyography, and 9 subjects without CP. Results indicated that peak torque was considerably greater in the comparison group than for each of the CP groups and resistance was greater in the CP group with spasticity compared to the nonspastic CP group in both muscles at all speeds. Stiffness differed between the spastic CP group and the comparison group only for the quadriceps at the fastest speed. Higher passive resistance torque and stiffness were correlated with decreased voluntary torque, particularly for the antagonists, and with lower GMFM scores. In conclusion, strength and motor function are related to the magnitude of resistance torque and stiffness in CP, although the small amount of variance explained reinforces the multidimensional nature of this disorder, and the challenges inherent in managing it.

RELATION OF GAIT ANALYSIS TO GROSS MOTOR FUNCTION IN CEREBRAL PALSY

The Gross Motor Function Measure (GMFM) and computerized gait analysis are commonly used to assess patients with cerebral palsy (CP). The authors investigated correlations between the GMFM and gait parameters in 32 children aged 3 to 18 (mean 8.9) years with spastic CP. Of the gait parameters, cadence and normalized velocity correlated most strongly with the GMFM score, and hip and knee excursion and percentage single support also correlated directly with the GMFM. In a stepwise multiple regression, cadence alone was a significant predictor of GMFM score. Time and distance parameters, hip and knee excursion in the sagittal plane and GMFM values all moved consistently further from pediatric norms as functional severity increased. The study confirms that gait is representative of general motor status in CP and that the GMFM and gait analysis are complementary measures in the functional assessment of these children.