Epilepsy among Cerebral Palsy Children: Clinical Predictors and Frequency

Introduction: Epilepsy is one of the most common neurological disorder in childhood. The risk of epilepsy is highest in children with brain abnormalities, such as cerebral palsy. There are a lot of studies showing that epilepsy varies from 12-19 percent in children with CP. Objective: The objective of this study is to determine the relationship between cerebral palsy (CP) and epilepsy and how to predict development of seizures among cerebral palsy children. Subject and Methods: A prospective study included 82 patients with cerebral palsy and history of seizure. Seizure were classified according to ILAE classification, an EEG and neuro-imaging were obtained in all cases. We analyzed the incidence of different types of epilepsy in relation to different subtypes of cerebral palsy. Other factors associated with epilepsy such as age of starting first attack, neonatal seizures and familial factors were also analyzed. Results: In our study the most common risk factors were perinatal factors 40 patients (48.8%): 16 of them had epilepsy. While the less common risk factors were postnatal factors 10 patients (12.2%): 6 of them had epilepsy. The incidence of epilepsy in our sample was significantly higher Original Research Article Salam et al.; INDJ, 6(2): 1-8, 2016; Article no.INDJ.22785 2 with very sever types of CP affecting 58.8% of very sever CP (P = 0.007). In contrary the mild type of CP was significantly associated with 3% only of the prevalence of epilepsy (P = 0.05). Abnormal CT brain findings were found in only 19 (39.6%) patients and there was no abnormality in CT brain in 29(60.4%) patients. High prevalence of epilepsy was associated with neonatal seizures and positive family history of epilepsy (p<0.005). Conclusions: Epilepsy among children with CP is common and the most common risk factors were perinatal factors. The predominant form of epilepsy was generalized. Brain CT imaging allowed definition of extent of associated brain damage and mostly significant frequency of abnormal findings were detected in epileptic CP children.


INTRODUCTION
Cerebral palsy (CP) was first described in 1862 by an orthopedic surgeon named William James Little [1], a motor disorder resulting from nonprogressive (static) hurt of the immature nervous system caused by several factors that have occurred in prenatal, perinatal or postnatal periods [2][3][4][5]. It is one of the three most common lifelong developmental disabilities, the other two being autism and mental retardation causing severe disabilities affecting children and their families [6]. It can manifest itself in different pictures, mainly as spastic, athetoid and ataxic palsies; moreover, it is one of the most common causes of motor disability in children and frequently is associated with other problems, such as mental retardation, speech disorder and other disabilities such as epilepsy [7].
The prevalence of epilepsy in general childhood population, is between 3 and 6 per 1000 [8]. Overall, this prevalence raising between 15 and 55% of children and adults with CP [9,10]. Also, if learning disability associated, the risk to children with CP to develop epilepsy is much higher, rising to 71% [11].
Some authors contend that in certain types of CP occur higher rate of epilepsy [12] and has been seen that about one third of the patients with CP exhibit seizures and this is proportional to the degree of motor and cognitive disabilities [13,14].
Neurophysiology and neuro-imaging are inclined to be supportive in the identification of the underlying pathology, and in diagnosis and management [15]. EEG is extremely critical assistant of the analysis for epilepsy. EEG could be precise useful, both in adding support to a probable diagnosis of epilepsy, further more for serving to categorize the vicinity or absence of a certain epilepsy syndrome [16].
Imaging might both identify underlying reason for neurological deficits and provide information about the feasibility and practicalities of surgical treatment. A wide range of developmental and acquired lesions might be recognized [15,17]. Specially to genetic and prognostic factors, it will be essential that the underlying lesion is defined as completely as possible [15].

OBJECTIVE
The objective of this study is to determine the relationship between cerebral palsy (CP) and epilepsy and to determine the risk factors and to classify seizure incidence and type in relation to the CP subtypes and how to predict development of seizures among cerebral palsy children.

SUBJECT AND METHODS
82 patients with cerebral palsy were included in this prospective study and conducted at outpatient clinic of both Neurology and Pediatrics Departments, at Saudi German Hospital, KSA since Jan 2014 till Oct 2015, in corporation with Neurology Department Mansoura University, Egypt. Thorough history taking was done for all children with CP including age at time of gestation, occurrence of pregnancy-related complications, mode of delivery and prenatal, perinatal and postnatal complications, maturity (pre-term, full term, or post-term). Age and gender of patients were defined. The etiology might have been recognized perinatal if there was history of pregnancy prompted hypertension, hypoxic ischemic encephalopathy, neonatal sepsis, alternately historical backdrop of punctual hospitalization after conception. Though the history proposed manifestation after 7 days, the cause was considered to be postnatal. CP might have been ordered as stated by tone and motor deficit into atonic and spastic (diplegia, hemiplegia, and tetraplegia including dyskinetic type). Frequency of epilepsy in CP patients was significantly higher with very sever types of CP affecting 58.8% of very sever CP (P = 0.007). while, less sever and moderate types of CP were associated with less prevalence of epilepsy (20.6% and 17.6 respectively). In contrary the mild type of CP was significantly associated with 3% only of the prevalence of epilepsy (P = 0.05).
The recurrence of epilepsy was highest in patients with spastic quadriplegic type disease (50%) but not statistically significant (P=0.1294), followed by hemiplegic type in 13 patients (38.2%), then diplegic type affecting 3 patients only (8.8%), and lastly the mixed type in one patient (3%) only. While there were no epileptic cases among dyskinetic, ataxic, and hypotonic types.
A total of 41% of the CP patients had epilepsy, 24% had mental retardation, 23% of patients had speech impairments, and 22% of CP patients had visual disorders. While, growth retardation, behavioral disorders, teeth problems, and dysphagia were less common manifestations of CP patients (Fig. 1).
Thirty-four CP patients were epileptics and abnormal CT brain findings were found in 28(82.4%) patients (ventriculomegaly,focal infarctions, periventricular leukomalacia, cortical and subcortical atrophy, basal ganglionic lesions), and there was no abnormality in CT brain in 6(17.6%) patients.  Forty-eight CP patients were non-epileptics and abnormal CT brain findings were found in only 19(39.6%) patients and there was no abnormality in CT brain in 29(60.4%) patients. High prevalence of epilepsy was associated with neonatal seizures and positive family history of epilepsy (p<0.005).

DISCUSSION
Epilepsy is a standout amongst the vast majority pervasive neuro-impairment in childhood and is appeared in 4.0 to 8.8 per 1000 in populationbased studies [22]. The incidence of epilepsy in our sample was significantly higher with very sever types of CP affecting 58.8% of very sever CP (P = 0.007). While, less sever and moderate types of CP were associated with less prevalence of epilepsy (20.6% and 17.6 respectively). In contrary the mild type of CP was significantly associated with 3% only of the prevalence of epilepsy (P = 0.05). May be identified with those of higher degree of motor and mental disorder of the patients concerned in these population, this is in accordance with several studies found that the incidence of epilepsy in cerebral palsy children is related to severe form of motor and mental abnormalities in the patients included in their group [23][24][25][26].
The predominant type of seizure in our study was generalized, which is in accordance with other studies concerned with children with or without CP [25,27,28]. Niedemayer [29] advocated this findings stating that the generalized epileptiform activity can be attributed whichever with a genetic predisposition, or to a quick secondary bilateral synchronization, for example the one induced sometimes by a frontal focus. On extraordinary occasions, deep subcortical cerebral lesion could also produce this type of epileptiform activity.
Also we found that The frequency of epilepsy was highest in patients with spastic quadriplegic type disease (50%) but not statistically significant (P=0.1294), followed by hemiplegic type in 13 patients (38.2%), then diplegic type affecting 3 patients only (8.8%), and lastly the mixed type in one patient (3%) only. While there were no epileptic cases among dyskinetic, ataxic, and hypotonic types. That is go in hand with Bruck et al. [30] who specified that there may be straight association between epilepsy and degree of motor dysfunction, furthermore their association with mental retardation. Also in their study they found that the majority of tetraplegic patients presented epilepsy and intellectual impairment.
Thirty-four CP patients were epileptics and abnormal CT brain findings were found in the majority (82.4%) of them, while normal CT findings were concluded in only 6 of 34 patients with CP and epilepsy and there is a significant higher frequency of abnormal CT brain in epileptics CP patients in comparison to nonepileptic CP patients (p<0.001). These findings indicated the applicability of neuroimaging for evaluation of both CP and epileptic patients. However, still CT imaging is not conclusive in patients with cerebral palsy as it is restricted in diagnosis of many cases with congenital abnormalities and cortical dysplasia, and so, in farther studies we recommend to do MRI imaging rather than CT studies. In line with this finding, Banerjee et al. [31] found that out of the epileptics who had brain CT scans 23.4% demonstrated single or multiple lesions suggestive of neurocysticercosis. Grigore & Diaconu reported that in 85.28% of CP patient's MR/CT imaging showed different types of abnormalities, CT/MR abnormalities might have been cohorted on 65.45% of cases with mental retardation, furthermore 44.54% exhibited epileptic seizures, also closed that in CP neuroimaging findings are common, but variable and MRI/CT change correlates with neurological appraisal [32]. Tripathi et al. [33] reported that radiological findings of structural cerebral abnormality is significant predictor of response, delayed milestones, high initial seizure frequency of more than you quit offering on that one for every month.

CONCLUSION
The obtained results concluded that epilepsy among children with CP is common and the most common risk factors were perinatal factors. with predominant of generalized form. Also; abnormal neuro-radiological findings associated with brain damage and EEG are mostly significant and we recommend to do them for all cerebral palsy children specially moderate or severe form and spastic quadriplegic type, for early detection of epilepsy in CP children and so the best line of management could be carried out.

CONSENT
It is not applicable.

ETHICAL APPROVAL
It is not applicable.