Effects of Hyperbaric Oxygen Therapy on children with Spastic Diplegic Cerebral Palsy     

     A Pilot Project

Montgomery, D., Ph.D., Goldberg, J., M. Sc., P.T., Amar, M., M.D.., Lacroix, V., M.D.

Lecomte, J., M.A., Lambert, J., Ph.D., Vanasse, M.,M.D.,  Marois, P., M.D.

 Affiliations:                     

1 McGill University

Hôpital Sainte-Justine

Hôpital Marie Enfant

Institut Maritime de Rimouski

Université de Montréal

Correspondence:

Dr. David Montgomery, McGill University

475 Pine Ave. West Montreal, QC, H2W 1S4

Tel: 514-398-4184 ext. 0558,   Fax: 514-398-4186

E-mail davidlm@glen-net.ca                   

August 21, 1999

  Abstract

HBO therapy for children with cerebral palsy (CP) is not new. Research documenting the effects in this population has been anecdotal. We evaluated the effects of HBO therapy for 25 children (X = 5.6 ± 1.6 years) with a functional diagnosis of spastic diplegic CP. Pre and post HBO evaluations consisted of the following measures: gross motor function (GMFM); fine motor function (Jebsen test for hand function); spasticity (modified Ashworth scale); video analysis; and parental questionnaire. The protocol for HBO therapy was 20 treatments of 95% oxygen at 1.75 atm abs for 60 minutes. The Wilcoxon matched pairs signed rank test for non-parametric measures was used to compare pre and post treatment data. Results showed improved gross motor function in 3 of the 5 items in the GMFM test, improved fine motor function in 3 of the 6 hand tests. reduced spasticitv in 3 of 4 muscle groups when assessed by a physician specializing in CP, and improvements for 4 of 9 questions posed to parents. HBO therapy appears to be a promising treatment for children with CP.

Key Words: Hyperbaric Oxygenation, Cerebral Palsy, Pediatrics

  Introduction

Cerebral palsy (CP) is a collection of diverse syndromes characterized by disorders of movement and posture caused by a non-progressive injury to the immature brain (1). The brain injury leading to CP can occur in the prenatal,  perinatal, or postnatal period (2). Almost half of all children with CP were born prematurely. The combination of immaturity, fragile brain vasculature, and the physical stresses of prematurity combine to predispose these children to compromised cerebral blood flow (3). In these children the cause of the brain injury is often elusive. The average prevalence rate for industrialized countries has been estimated at 2 per 1000 live births (4).

Cerebral palsy is classified two ways: by the type of muscle tone abnormality and the areas of the body that are affected (5). Increased muscle tone or spasticity is defined as a motor disorder characterized by a velocity dependent increase in tonic stretch reflexes (muscle tone) with exaggerated tendon jerks resulting from hyperexcitability of the stretch reflex, as one component of the upper motor neuron syndrome (6,7). Spasticity affects approximately 75% of all patients with CP (8,9). When characterized by body part, diplegia is the most common type. In spastic diplegia, there is an interruption of the pyramidal fibers originating from the cortical motor region that leads to spasticity. Hyperactivity of the alpha motor neurons results in spasticity, increased muscle tone, and hyperreflexia. Abnormalities of muscle tone are frequently accompanied by muscle weakness.

In order to improve motor function, treatments are often directed at reducing the spasticity in persons with CP. Pharmacology, surgery and physical therapy have been the standard approach for treatment of children with CP. Medications for spasticity are limited and sometimes have undesired side effects. Surgery, particularly selective dorsal rhizotomy, is the most effective treatment in reducing spasticity but not all children with CP are appropriate candidates for this procedure (10, 1). Few studies have documented long term improvements from physical therapy (12.13,14).

Hyperbaric oxygen therapy (HBO) has been used to treat children with CP for a number of years. Recently, there has been a return to this treatment in China. England. Germany. Russia. South Africa, and the United States. There is at the present time, no scientific evidence to support the use of HBO to treat these children. One anecdotal report (15) summarized the clinical-experience in Brazil showing a reduction in spasticity following HBO treatments for patients with neurological impairments. Due to the desire of parents to seek out this treatment for their children at significant financial expense, we felt it was our responsibility to objectively evaluate the efficacy of HBO treatment for persons with CP prior to recommending this option to parents. The objectives in this pilot study were to examine if HBO treatments would alter: (1) gross motor function, (2) fine motor control, and (3) muscle spasticity in children with CP.

  Methods

Subjects: Twenty-five volunteer subjects with a mean age 5.6 ± 1.6 years (range 3.1 - 8.2 years) participated in this study. Subjects consisted of 10 girls and 15 boys with a functional diagnosis of spastic diplegia. Potential subjects were obtained by referrals from rehabilitation centers in Quebec and/or requests from parents. In order to be considered for participation in the study, subjects had to meet the following inclusion criteria: 1) functional diagnosis of spastic diplegia; 2) age range from 3 to 8 years; 3) functional plateau in rehabilitation for the last 12 months (defined as no measurable functional changes in gross motor performance as documented by their physical therapist); 4) ability to understand and respond to verbal instruction; and 5) medical clearance for HBO therapy. Children were excluded from: the study if any of the following criteria were present in their medical history: previous rhizotomy, recent thoracic surgery, epilepsy, cancer, chronic asthma, ventriculo-peritoneal shunts and previous HBOT therapy. In addition children taking anti-spasticity medication or those with behavior problems were also excluded.

Of the 60 children that met the inclusion/exclusion criteria, 25 were randomly selected. Informed consent was obtained from the parent or legal guardian of each child prior to participation in the study. The study was approved by ethical review committees at McGill University in Montreal and the Regional Hospital in Rimouski, Quebec. No children received physical or occupational therapy during the course of the study.

Procedures: The same therapists conducted pre and post treatment evaluations which were separated by 37.2 ± 8.0 days. The procedures for these evaluations were identical and are outlined below. The physical and occupational therapists worked in a hospital setting and were accustomed to administering the GMFM test Jebsen test and modified Ashworth scale. They had no contact with the children during the HBO treatments. Each evaluation consisted of the following five tests:

1. Gross Motor Function: The Gross Motor Function Measure (GMFM) was used since it is a standardized index of gross motor function for children with cerebral palsy (16,17). The GMFM is a criterion based observational measure (88-items) that assesses motor function in five dimensions. The five dimensions and their respective maximum scores are: A =lying and rolling (51), B = sitting (60), C = crawling and kneeling (42), D = standing (39), and E = walking, running and jumping (72). Each item is scored on a 4-point scale (0 = does not initiate activity, 1 = initiated activity, 2 = partially completes activity, 3 = completes activity). Specific descriptions on how to score each item are found in the administration and scoring guidelines in the test manual (18). The physical therapist who administered the test had been trained and had several years experience using the test. Subjects completed each item of the GMFM test and were given a score for each dimension by the physical therapist.

2. Fine Motor Function: Fine motor function was evaluated with the Jebsen Test, which is an objective and standardized 7-item assessment of hand function (19). An occupational therapist administered the following 6 items or sub-tests: 1) turning over 3 by 5 inch cards: 2) picking up small objects and placing them in a container: 3) stacking checkers; 4) simulated eating; 5) moving empty large cans; and 6) moving weighted large cans. The seventh item (writing a short sentence) was omitted due to the age of some of the children. Subjects remained seated during the test. The sub-tests were presented in the same sequence, administered in the same manner and were always performed with the non-dominant hand first. After the instructions were given, the child was asked if he/she understood the task to be performed before starting the sub-test. Each task was timed by the occupational therapist with a score in seconds recorded for each sub-test for the dominant and non-dominant hands.

3. Spasticity Level: Spasticity was evaluated using the modified Ashworth scale (MAS) (20) in four muscle groups (hip adductors, quadriceps femoris, hamstrings. and ankle plantar flexors). Spasticity was graded from 0 (no increase in muscle tone) to 4 (affected part rigid in flexion or extension) on a 6-point scale. During the pre and post evaluations, spasticity was evaluated separately by a physician and physical therapist with each assigning a score for the level of spasticity for each muscle.

4. Video Analysis: Subjects were recorded on videotape pre and post treatment performing numerous gross motor and fine motor tasks (e.g. pedaling their legs, rolling, sitting, crawling. standing, walking, reaching and coloring). Each videotaping session was recorded on a separate cassette with no date or time stamp. The videotapes were randomly analyzed by 2 pediatric physical therapists and were only viewed at the end of the study. The physical therapists were blinded and did not know if they were viewing a performance pre or post HBO therapy. Therapists viewed the pre and post tapes simultaneously on two monitors and rated one video as "better” if motor function was improved.

5.  Questionnaire: A 9-item questionnaire was administered verbally by the physical therapist to the same parent of each subject pre and post HBO therapy. The questionnaire included the following categories: 1) walking; 2) walking on knees; 3) crawling; 4) sitting on the floor: 5) sitting on a bench; 6) undressing; 7) eating; 8) bath and personal hygiene: and 9) communication. The scale of independence (5-point scale) for each category ranged from 0 to 4 (0 = dependent, no participation: 1 = dependent, participates but requires constant help throughout the activity; 2 = dependent, needs help only to finish the activity; 3 = independent with some form of aid or compensation: 4 = independent). Each category consisted of 3 - 4 questions in order to determine the child's level of autonomy and to assign the appropriate score.

HBO therapy: Subjects were randomly assigned to one of two hyperbaric oxygen treatment units. Ten children received HBO treatment at the Cleghorn Hyperbaric Oxygen Laboratory of McGill University and 15 children received HBO treatment at the Centre Hospitalier Regional de Rimouski. The protocol for the HBO therapy was 95% oxygen at 1.75 atm abs for 60 minutes. All subjects received 20 HBO treatments. The schedule of treatments at McGill University was: 1 treatment/day; 5 days/week for 4 weeks in a monoplace hyperbaric chamber (Sigma Plus Monoplace Hyperbaric System, Perry Baromedical, Riviera Beach, FL) that was pressurized with 95% oxygen. During treatments, a parent or guardian accompanied the child in the hyperbaric chamber. The schedule of treatments at the Centre Hospitalier Regional de Rimouski was: 2 treatments/day; 5 days/week for 2 weeks in a multi-place (6 person) hyperbaric chamber that was pressurized with air and oxygen delivery to the patient via a hood. Pressure equalization (P.E.) tubes were inserted in the ears of 13 children to facilitate compression discomfort in the multi-place unit.

Data Analysis: For data analysis, each child served as his/her own control by using pre HBO scores as the baseline for comparison. Since the children ranged in age from 3 to 8 years of age, measurements of the dependent variables resulted in large inter-individual variability. The mean and S.D. results for each dependent variable are summarized for pre and post evaluations. In addition, the data for the GMFM test were analyzed to determine the percent change between pre and post evaluations for each child. The Wilcoxon matched-pairs signed-ranks test was used to determine significant changes from the pre to post test for the GMFM test, functional evaluation of the hand, spasticity evaluation, and the 9-item questionnaire to the parents. Statistical significance was determined if p < 0.05.

  Results

Results of the GMFM are illustrated in Table 1 as a percentage of the maximum score for each dimension. Maximum scores were: A (51), B (60), C (42), D (39), and E (72). Significant (p <0.05) improvements from pre to post evaluation were observed for dimensions B (sitting), D (standing) and E (walking, running, jumping). Table 1displays the results of the GMFM test for each child. The average improvement in the total GMFM score was 5.3%.

Table 1. Individual Results for the GMFM Test.
	Item A		Item B		Item C		Item D		Item E		Total		Percent
Subject	Pre	Post	Pre	Post	Pre	Post	Pre	Post	Pre	Post	Pre	Post	Change
1	51	51	57	57	30	39	17	26	14	18	169	191	13.0%
2	35	36	16	12	1	0	0	4	1	3	53	55	3.8%
3	51	51	60	60	42	42	39	38	71	71	263	262	-0.4%
4	49	51	57	59	37	38	20	21	10	13	173	182	5.2%
5	10		10		0		0		0		20
6	51	51	58	59	40	40	32	32	50	50	231	232	0.4%
7	49	48	34	36	5	12	1	5	3	3	92	104	13.0%
8	41	45	35	33	25	21	8	4	2	2	111	105	-5.4%
9	51	51	59	59	34	35	22	26	14	15	180