Infants and young children with spastic cerebral palsy (CP) do well with a single daily dose of diazepamgiven at bedtime, as the muscle relaxation decreases the spasticity and faciltates both passive and voluntarymovements. This double blind randomized control trial showed that reducing the hypertonia enhanced thechild’s mobility and quality of life without causing daytime drowsiness. The traditional method of assessingthe muscle tone is by using the Ashworth’s scale. However this is a subjective measurement and inter-rater variability is invariably present. The angle of plantar flexion at the ankle was measured in this study using a goniometer and compared with the Ashworth scores to study if it is a valid and reliable indicator of musclerelaxation. Measuring the angle of plantar flexion is easy to perform and is an effective and objective tool to monitor the dose of diazepam required for optimum muscle relaxation

Antonisamy B

Ernest KM

Macaden AS

Mathew A

Mathew MC

Indian Journal of Physical Medicine and Rehabilitation

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(11)EditorialIJPMR 2007 April; 18 (1): 11-14Address for correspondence: Dr. Anna Mathew, Reader , Departmentof Pharmacology, Coordinator, Continuing Medical Education,Department of Continuing Medical Education, Christian MedicalCollege, Vellore 632 002. Tamil Nadu. INDIA.Email -ashirvad@cmcvellore.ac.inMeasurement of the Angle of Plantar FlexionAn Objective Way of Assessing Muscle Relaxation inChildren with Spastic Cerebral PalsyDr Anna Mathew, MBBS, MD (Pharmacology), Reader*Dr MC Mathew, MBBS, MD (Paediatrics) , Ph D (Neurology),  DNB (Maternal & Child Health),DCBR (London), DPH, Consultant & Professor in Developmental Neurology$Dr Ashish Stephen Macaden, MBBS, DNB (PMR), PhD, Reader#Dr B. Antonisamy,  MSc, PhD (Biostatistics), Professor@Dr Kalpana M Ernest,  MBBS, MD (Pharmacology), Professor***Department of Pharmacology, Department of Continuing Medical Education$Developmental Paediatric Unit# Department of Physical Medicine and Rehabilitation@ Department of Biostatistics** Department of Pharmacology,Christian Medical College & Hospital, Vellore, Tamilnadu, Indiaspasms play a significant part in the performance deficits(negative symptoms) like weakness of limbs anddecreased motor activity1. Children with hypertonia arefrequently in distress because of muscle spasm and painon movement of the limbs. For the same reason theyshun movement and are often reluctant to allow passivemovement of the limb.Over the years many drugs have been used to treatspasticity and diazepam has proved particularly effective2.The clinical response of improved mobility followingmuscle relaxation brought about by diazepam and theconsequent decrease in painful muscle spasms,improvement in motor activity and decrease in sleepdisturbances suggest that diazepam has a role inencouraging movement in children with spasticity causedby spastic CP3. When the spasticity that hindersAbstractInfants and young children with spastic cerebral palsy (CP) do well with a single daily dose of diazepamgiven at bedtime, as the muscle relaxation decreases the spasticity and faciltates both passive and voluntarymovements. This double blind randomized control trial showed that reducing the hypertonia enhanced thechild’s mobility and quality of life without causing daytime drowsiness. The traditional method of assessingthe muscle tone is by using the Ashworth’s scale. However this is a subjective measurement and inter-ratervariability is invariably present. The angle of plantar flexion at the ankle was measured in this study using agoniometer and compared with the Ashworth scores to study if it is a valid and reliable indicator of musclerelaxation. Measuring the angle of plantar flexion is easy to perform and is an effective and objective tool tomonitor the dose of diazepam required for optimum muscle relaxation.Key Words : Diazepam, plantar flexion angle, spastic cerebral palsy, goniometer, hypertonia,IntroductionOne of the key clinical features of spastic cerebral palsy(CP) is that hypertonia leads to paucity of movements.The voluntary movements and range of passivemovements are limited in children with CP.  As the motoricresponses are reduced the motor milestones are delayed.The muscle tone is increased and the deep tendon reflexesare brisk and sustained ankle clonus may be present.Some infants with marked spasticity may show extensorhypertonus affecting trunk and neck muscles. The positivesymptoms, such as exaggerated reflexes and flexor(12)Editorialmovement is reduced, it is possible to initiate motor activityand play based learning and consequently there is progressin the motor developmental sequences. A single bedtimedose of diazepam causes adequate muscle relaxation topromote motor activity without making the child drowsyduring the day4.Hypertonia and spasticity of the muscles cause the ankleto be fixed in plantar flexion5. Reduction of spasticity willreduce the abnormal posture and physical therapy willhelp the joint to return to the optimum position6. Whenthe muscle is relaxed, the angle of plantar flexion (APF)at the ankle is around ninety degrees, the calf musclestouch the couch in the supine position and in the uprightposition the child is able to place the feet plantigrade onthe ground and experience weight-bearing7.The monitoring of muscle relaxation is difficult and oftendependent upon subjective evaluation. The lack of sucheffective measurement techniques has been a limitationin the ability to judge the efficacy of pharmacological orphysical therapies8. This restricts the quantification ofmuscle relaxation and therefore the assessment ofhypertonia has been based primarily on observerdependent measurements. Although clinical scales offeronly qualitative information they have been widely usedin the study of spasticity and are the present yardsticksagainst which newer and more exact methods must becompared9.The traditional method of assessing the muscle tone is byusing the Ashworth’s scale (AS), which is a five pointgross clinical scale to grade muscle tone from 0 (normal)to 4 (severe). This rating scale was first proposed byAshworth10 and grades the severity of hypertonia topassive limb movement with reasonable inter-raterreliability11.As the AS is a subjective test, based on the assessmentof the tone by moving the limb and gauging the resistance,we looked for a more objective tool to monitor the musclerelaxation achieved with diazepam. Quantitativemeasurements of joints have been used as a basis forassessing effectiveness of therapeutic intervention12. Wemeasured the angle of plantar flexion (APF) to test itsefficacy as a tool to measure muscle relaxation.In this placebo-controlled, double blind randomised trial,to study the efficacy of diazepam as a muscle relaxant inspastic cerebral palsy, we compared the AS score to theAPF score in monitoring muscle relaxation. The APF atthe ankle is an index of the spasticity of the gastrocnemeusand soleus13 and is an objective tool for monitoring themuscle relaxation at the ankle. The goniometricmeasurement of the APF of the affected ankle with thechild in the supine position and the knee kept in fullextension14 is shown in  Image 1.The aim of this study was to establish if the change in theAPF after using diazepam as a   muscle relaxant is aspecific and sensitive index for titrating the optimum doseof diazepam required for adequate muscle relaxation. Asthe APF indicates the status of the gastrocnemeus-soleus,the scores for the change in APF will reflect musclerelaxation while the child is receiving diazepam. Thecorrelation between the APF and the AS scores achievedwith a bedtime dose of diazepam, will provide the evidencethat the APF is a reliable and valid tool to measure musclerelaxation.Material and MethodsOne hundred and eighty children diagnosed to have spasticcerebral palsy were recruited serially to study the efficacyof diazepam to reduce hypertonia and facilitatemovement. All children recruited to the study were firstweighed and allocated to Category A if they weighedless than 8.5 Kg and to Category B if they weighed 8.6Kg to 15 Kg. Of the 90 children recruited to Category A(< 8.5 Kg), 37 were girls and 53 were boys and of the 90children recruited into Category B (8.6-15 Kg), 32 weregirls and 58 were boys. All children in Category A werebelow the age of 5 years while in Category B, 17 childrenwere over five years of age.The children received one of the two doses of diazepamor placebo (lactose & starch) at bedtime. The double-blinded regimen was selected by random allocation usingthe method of equal allocation by Clinstat Computerrandomisation. Children from Category A randomlyreceived 1 mg of diazepam or 0.5 mg of diazepam orplacebo and children from Category B received 2 mg or1 mg of diazepam or placebo, with 30 children in eacharm of each category. The muscle tone was graded usingthe AS and the muscle relaxation by measuring the APFwith the help of a goniometer (Fig 1). The data wereanalysed using the Statistical Package for Social Sciences(SPSS) using the one-way analysis of variance(ANOVA). The primary outcome and details of this studyhave been published elsewhere.3, 4.Fig. 1 Measuring the angle of plantar flexion with the helpof the goniometer, baby in supine position.Anna Mathew, MC Mathew(13)EditorialObservationsAssessing Muscle RelaxationThe muscle relaxation was assessed using the AS andquantified by measuring the APF.  The decrease in muscletone was found to be comparable.A. Assessing the muscle tone using ASThe muscle tone was assessed using the specified criteriaand graded using the AS (1964) for clinical assessmentof tone as given in table 1.B. Monitoring the muscle tone using the APFThe APF at the ankle was measured at rest with theknee in full extension with the help of a goniometer(Image 1) at the first visit and again after three weeks ofstarting the drug regimen. The APF was measured ateach ankle and the more affected side was taken intoaccount. This procedure was repeated after 3 weeks ofadministration of the drug and the difference in the APFwas carefully noted and the mean values for each groupobtained to study if there was a dose dependent changein the APF with diazepam.ResultsThere was a significant difference in the scores for muscletone after administering diazepam indicating that both thedoses of diazepam produced significant muscle relaxationcompared to placebo (Table 1 & Fig 2). This was evidentin the lowered AS scores and the reduced APF at theankle.The AS score change for the 173 children who completedthe study was as follows:· 0.5 (SD 10.5) in the 55 children who receivedplacebo· 8.5 (SD 7.4) in the 60 children who received 0.5/1mg diazepam and· 13.3 (SD 6.2) in the 58 children who received 1mg/2mg diazepam.The mean change in the APF for the 173 children whocompleted the study was as follows:· 0.4 (SD 7.8) in the 55 children who receivedplacebo· 7.4 (SD 8.5) in the 60 children who received 0.5/1mg diazepam and· 13.4 (SD 7.7) in the 58 children who received 1mg/2mg diazepam.The mean APF before treatment was 120.0 with astandard deviation of 7.6. After treatment the mean APFin the children who received diazepam (all doses n =118) was 109.5 with a standard deviation of 10.4. Themean APF at the ankle in the children who received 1mg/2mg diazepam decreased from 119.7 before treatmentto 106.3 after treatment, while in the children whoreceived 0.5/1mg diazepam, the mean APF reduced from119.9 at first visit to 112.5 after treatment. In the placebogroup the APF was initially 120.4 and after treatment themean APF was 120.0.Table 1. ASHWORTH  SCALE FOR CLINICALASSESSMENT OF TONEScore 0 No increase in tone  ( 0-normal )Score 1 Slight increase in tone, giving a catch whenlimb is moved in flexion or extension( 1-catch )Score 2 More marked increase in tone but limb canstill be easily flexed ( 2-tight flexion/extension )Score 3 Considerable increase in tone; passivemovement difficult ( 3-passive movementdifficult )Score 4 Limb rigid in flexion or extension ( 4-rigid )Ashworth (1964)Table 2.  Mean Score Change in the AshworthScale (AS) and in the Angle of Plantar Flexion(APF) in the Three Study GroupsMean Score Change(SD)Placebo 0.5/1 mg 1 / 2 mg P value*diazepam diazepamChange in Ashworth 0.53 8.53 13.32 < .001Score (AS) (SD 10.5) (SD 7.4) (SD 6.2)Change in Angle 0.44 7.35 13.41 < .001of Plantar Flexion (SD 7.8) (SD 8.5) (SD 7.7)(APF) at Ankle* P value calculated by Analysis of Variance (ANOVA)Fig. 2 Dose response relationhip for change in plantarflexion angleMonitoring muscle relaxation in CP(14)EditorialDiscussionMeasuring the APF is a simple procedure that can bedone in the outpatient setting using a hand held goniometer.The change in APF with the higher dose of diazepam (1/2 mg) is almost two fold that of the change with thelower dose (0.5/1 mg), which was significantly greater(p value < .001) than the change with placebo. The studyalso showed that there was a significant improvement inboth the range of movement (ROM) and the voluntarymovement3. Thus the APF at the ankle can be used as atool to monitor the dose of diazepam required to produceadequate muscle relaxation.The change in the APF is the response compared to thedose of diazepam illustrated in the dose-response graphin Figure 2. The change in the APF after giving theregimen is plotted on the y axis and the predictor variable(the dose) on the X axis.The variable y = a (constant) + bx (slope x dose).Therefore the change in the angle of flexion(y) = 5.64 +(6.382 x dose).The coefficient of determination for the change in theAPF = 0.961.It is seen that the muscle relaxation caused by increasingdoses of diazepam is reflected linearly in the change inAPF. This graph shows that 96.1% of the variation inAPF can be explained by the dose of diazepam which ishighly significant as the p value is < 0.001.ConclusionThe measurement of the APF with the help of agoniometer is a simple and practical way of assessingmuscle relaxation in the outpatient setting both to monitorthe dose of diazepam required for adequate musclerelaxation and as an objective parameter in planning aprogramme of physical therapy.AcknowledgementsWe are grateful to all the parents and children whoparticipated in this study and to Ms. Premila John andMr. T. Suresh Babu for helping in various ways.We are also grateful to the Director, Principal and MedicalSuperintendent of Christian Medical College & Hospitalfor permitting publication of this study.References1. Brett E.M, Scrutton D. Cerebral Palsy in PaediatricNeurology 3rd edition Brett E. M. (editor): ChurchillLivingstone; 1997. 312.2. Aicardi J, Bax M. Cerebral Palsy in Diseases of theNervous System in Childhood: Jean Aicardi (editor).Clinics in Developmental Medicine 2nd editionMacKeith Press 1998. 210 - 233.3. Mathew A, Mathew M.C, Thomas M, AntonisamyB. The Efficacy of Diazepam in Enhancing MotorFunction in Children with Cerebral Palsy. Journal ofTropical Paediatrics, 2005. 51(2)109-113.4. Mathew A, Mathew M.C.  Bedtime diazepamenhances well being in children with spastic cerebralpalsy. Paediatric Rehabilitation 2005. 8 (1). 63-66.5. Erickson R.P, MCPHEE M.C. In: Clinical Evaluationin Rehabilitation Medicine Principles and Practice,3rd edition. Lippincott-Raven Joel A. DeLisa andBruce M. Gans. (editors): 1998, 72-107.6. Campbell S. K. Decision Making in PaediatricNeurologic Physical Therapy. Churchill Livingstone.1999. Cerebral Palsy 23-75.7. Mathew A. The role of low dose diazepam in centralmotor dysfunction. Promoting Childhood Wellbeing,“Vellore Experiences”. Published by DevelopmentalPaediatrics Unit, Christian Medical College &Ashirvad Christian Concern for Child Care. EditorM. C. Mathew 2002. 116-1248. Katz R. T. Management of Spasticity in PhysicalMedicine & Rehabilitation Randall L. Brandon W.B.Saunders & Co. 1996 chapter 29: 580 - 604.9. Christopher Robert P, Gans B. M. Rehabilitation ofthe Paediatric Patient in Rehabilitation MedicinePrinciples and Practice 3rd edition 1998 Editors-JoelA Delisa, Bruce M. Gans: 946 - 950.10. Ashworth B. Preliminary trial of carisoprodol inmultiple sclerosis Practitioner 1964: 192: 540-542.11. Bohannon R.W, Smith M.B. Interarater reliability ofa modified Ashworth scale of spasticity. Phys. Ther.1987.  67: 206-7.12. Lehmann J.F, Price R, De Lateur B.J, Hinderer S,Traynor C. Spasticity: Quantitative measurementsas a basis for assessing effectiveness of therapeuticintervention. Arch. Phys. Med Rehabil 1989; 70:6-15.13. Committee for the study of joint motion. AmericanAcademy of Orthopaedic Surgeons: Joint Motion:Method of Measuring and Recording. Chicago:American Academy of Orthopaedic Surgeons 1965.14. Norkin C.C, White D.J. Measurement of JointMotion: A Guide to Goniometry. 2nd edition.: 1995.F.A. Davis Company. Philadelphia.Anna Mathew, MC Mathew

Measurement of the Angle of Plantar Flexion An Objective Way of Assessing Muscle Relaxation in Children with Spastic Cerebral Palsy

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