|Year : 2007 | Volume
| Issue : 1 | Page : 7-9
Quantitative gait analysis following hemispherotomy for Rasmussen's encephalitis
Santhosh George Thomas1, Judy Ann David2, Suranjan Bhattacharji2, Roy Thomas Daniel1
1 Department of Neurological Sciences, Christian Medical College, Vellore, India
2 Department of Physical Medicine and Rehabilitation, Christian Medical College, Vellore, India
Roy Thomas Daniel
Department of Neurological Sciences, Christian Medical College, Vellore - 632 004, Tamil Nadu
Source of Support: None, Conflict of Interest: None
| Abstract|| |
Peri-insular hemispherotomy is a form of disconnective hemispherectomy involving complete disconnection of all ascending / descending and commisural connections of one hemisphere. We report a case of a seven and a half year old child with intractable epilepsy due to Rasmussen's encephalitis who underwent peri-insular hemispherotomy and achieved complete freedom from seizures. Quantitative gait analysis was used to describe the changes in the kinematic and kinetic parameters of gait with surface electromyographs 18 months after surgery. The focus of this paper is to highlight the utility of gait analysis following hemispherotomy with a view to directing postsurgical motor training and rehabilitation.
Keywords: Epilepsy surgery, gait analysis, hemispherotomy, Rasmussen′s encephalitis
|How to cite this article:|
Thomas SG, David J, Bhattacharji S, Daniel RT. Quantitative gait analysis following hemispherotomy for Rasmussen's encephalitis. J Pediatr Neurosci 2007;2:7-9
| Introduction|| |
Peri-insular hemispherotomy, a form of functional hemispherectomy, consists of disconnecting the entire hemisphere leaving viable but completely disconnected brain tissue.  The ratio of disconnection to excision is the maximum in this surgery and can be best defined as a radical hemispheric tractotomy. In this case report, we focus on the quantitative changes in the gait of the patient with respect to the kinetic and kinematic parameters along with changes in surface electromyographs (EMGs). We also discuss the utility of such analyses to direct rehabilitation following such surgery.
| Case Report|| |
This seven and a half year old girl presented with complaints of left-sided focal motor seizures with frequent episodes of secondary generalization for 2 years which progressed in the last year to epilepsia partialis continua. She had progressive weakness on the left side along with progressive cognitive decline and had stopped schooling. Birth history and milestones of development were normal till the onset of seizures. She was found to be intractable to multiple anticonvulsants administered both as mono- and polytherapy. On examination, she had a left-sided homonymous hemianopia and upper motor neuron facial paresis. The motor power (MRC grading) on the right side was normal, while on the left it was as follows: upper limb proximally 4/5 and distally 3/5; lower limbs proximally 4/5 and distally 2/5. Thumb opposition was impaired on the left side with a weak hand grip. Her gait was a hemiparetic with circumduction at the hip. Routine investigations were normal, and anticonvulsant drug assays were within therapeutic limits. EEG showed focal slowing over right frontal lobe and epileptiform activity over the right frontal, central and temporal lobes. Magnetic resonance imaging (MRI) brain showed diffuse cortical atrophy on the right hemisphere, with a predominance to the perisylvian cortices [Figure - 1]. A diagnosis of intractable right hemispheric epilepsy with chronic epilepsia partialis continua was made on the basis of a good electro-clinico- radiological concordance. The clinical profile of the illness was suggestive of Rasmussen's encephalitis. She underwent a right peri-insular hemispherotomy. In the postoperative period, flaccidity with grade 0 power was noted distally in the left upper and lower limbs. There was complete remission of seizures. Antiepileptic drugs were continued at the same dose for 6 months and then tapered off. At follow-up visit 18 months after surgery, she remained in Engel's Class I seizure outcome. Spasticity had developed on the left-sided limbs with a power of upper limbs - proximally 4/5 and distally 0/5; lower limbs - proximally 4/5 and distally 0/5. She had resumed schooling and was independent in activities of daily living.
A detailed gait analysis was done in comparison to age-matched controls. A gait cycle is a cycle of repeated events involving a foot strike and toe off followed by contralateral strike and toe off. Gait is divided into the stance and swing phases: the stance phase is defined as the percentage of the cycle when the foot is in contact with the ground and the swing phase as the time the foot is in the air. Kinematic parameters consist of walking speed (meters/minute), stride length (distance in centimeters from the foot contact to the subsequent ipsilateral foot contact) and single-limb support time (period from opposite toe off to opposite foot strike). , There was slowing of gait with decreased single-limb support on the affected side [Table - 1]. There was circumduction gait on the affected side with a pelvic tilt and lumbar lordosis.
Kinetic parameters consisting of vertical, forward, backward, medial and lateral ground reaction forces were derived as a percentage of the body weight.  The hip and knee power generation (proximal) was near normal on the affected side [Figure - 2]A, B; however, there was poor power generation at the affected ankle [Figure - 2]C, D.
The dynamic EMG study was obtained by application of surface EMG electrodes over the following groups of muscles: hip flexor (rectus femoris), hip extensor (gluteus maximus), hip abductor (tensor fascia lata), hip adductor (adductor longus), knee extensor (vastus lateralis), knee flexor (medial hamstrings), ankle dorsiflexor (tibialis anterior) and ankle plantar flexor (soleus). The left hip flexor and hip abductor showed increased EMG activity in the mid-swing phase [Figure - 3]A, B. The left knee flexor showed prolonged EMG activity, and the ankle plantar flexors on the left side showed inappropriate EMG in the early stance [Figure - 3]C, D.
| Discussion|| |
The treatment of Rasmussen's encephalitis with intractable epilepsy by hemispherotomy achieved freedom from seizures in over 80% of patients in our experience and is well supported by reports from literature. Clinical examination following hemispherotomy in these cases frequently shows that there is a worsening of power on the affected side, both proximally and distally, which can improve proximally to almost presurgical status though the distal musculature may remain weak. Hand and wrist function suffers the most following insult (94% decline), followed by arm function (54% decline) and leg and foot function (45% decline) compared with the unaffected side.  Empelen et al . showed that the gross motor functional status improved in all domains of activity 2 years after surgery. All hemispherectomy groups had little wrist and hand control; the children whose seizures were due to sequelae of childhood vascular insults had some voluntary control spared and were capable of a weak grasp and / or pincer hold. This is due to reorganization of motor input , by the unmasking of relatively inactive representation with the takeover of function by undamaged brain tissue.  The upper extremities become skilled to perform fine movements and are more under the control of the corticospinal pathways while the locomotor task of the leg is more under the control of the spinal neuronal circuits. One reason for preservation of the ability to walk may be due to contributions of the subcortical regions of the nervous system to the neural control of walking. Both motor areas have a latent capacity to control motoricity bilaterally, and the ipsilateral cortical pathway control is unmasked only after removal of the opposite hemisphere. The number of uncrossed fibers which vary individually might also predict the degree of recovery of motor functions. ,, There are many reasons for activation of ipsilateral connections in the diseased brain. One is the strengthening of the ipsilateral connections in proportion with the functional demand - reorganization of the ipsilateral pathway or loss of inhibition of the ipsilateral pathway by the affected hemisphere, which is normally seen in cortical maturation of childhood. ,,,
An understanding of the changes in the various physiological parameters that are actually altered and their relationship to the change in the patient's clinical status would allow optimal planning of further treatment and rehabilitation. Excess spasticity can be controlled by medication / stretching exercises. Strengthening or endurance-building exercises can be taught for weak muscles. Ankle contractures can be prevented by the use of articulated AFOs. Neural reorganization can occur by forced non-use of the normal side. Finally a re-coordination of gait can be taught which can make the patient independent in the activities of daily living and improve the quality of their life.
Gait analysis can be used as a tool to quantitatively evaluate patients with hemispheric and sub-hemispheric epilepsy both pre- and postoperatively. An insight into the changes of motor function which can affect both sides helps to plan appropriate treatment and rehabilitation. This is crucial to make the patients independent in activities of daily living; it decreases caregiver assistance and improves their quality of life. Further studies of gait analysis and the changes in gait in a particular patient over time need to be done. In addition, descriptive studies to differentiate the gait analysis parameters between congenital and acquired forms of hemispheric disease should form the focus of research in the future. This could provide insight into mechanisms of neural plasticity and their duration in a growing child.
| Acknowledgments|| |
Dr. Suresh Devasahayam, Professor and Head, Bioengineering Department, Christian Medical College, Vellore. Mr. Ganesh, Gait Analyst, Christian Medical College, Vellore.
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[Figure - 1], [Figure - 2], [Figure - 3]
[Table - 1]