Biomedical subjects
Publications and source records attributed to Michael I Shevell.
The term "cerebral palsy" has had varied meanings over the past century. This article presents the current consensus definition that best captures the core elements of this heterogeneous entity. Elements comprising the components of the consensus definition are elaborated upon to provide clarity. Areas of remaining lack of consensus, mostly reflecting the timing of diagnosis and the exclusion of various etiologic entities are highlighted.
The terms "cerebral palsy," "neonatal encephalopathy," and "intrapartum asphyxia" are frequently used in pediatric neurology. This article presents concise, verifiable definitions for each of these entities based on our current understanding and formulates the nature of the interrelationships between them. The aim is to provide a level of clarity that will enhance diagnostic and pathogenetic precision and minimize conceptual misunderstanding. This should aid future therapeutic and research efforts in this important area.
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This review summarizes what is known about the neurobiology of specific language impairment. Despite its name, specific language impairment is frequently not specific. It is common to find associated impairments in motor skills, cognitive function, attention, and reading in children who meet criteria for specific language impairment. There is evidence that limitation in phonologic working memory may be a core deficit in specific language impairment. Both genetic and environmental factors have been shown to be important etiologic factors in specific language impairment. Structural neuroimaging studies suggest that atypical patterns of asymmetry of language cortex, white-matter abnormalities, and cortical dysplasia may be associated with specific language impairment. Abnormalities in the later stages of auditory processing have been demonstrated using auditory event-related potentials. Functional neuroimaging may cast further light on the neurobiology of specific language impairment and serve as a means of developing and evaluating therapy. A better understanding of the neurobiology of specific language impairment is critical for the rational development of therapeutic strategies to treat this common disorder.
Cerebral palsy is an established symptom complex that results from heterogeneous etiologies. Our understanding of the relative contribution of underlying etiologies to the occurrence of cerebral palsy is largely derived from studies lacking systematic neurologic evaluation or the application of contemporary imaging modalities. Throughout a 10-year inclusive period, the case records of all consecutive patients diagnosed with cerebral palsy in a single pediatric neurology practice were reviewed with reference to clinical features and diagnostic yield. A total of 217 cases of cerebral palsy were identified (129 male, 88 female): 77 (35.5%) spastic quadriplegic, 68 (31.3%) spastic hemiplegic, 39 (18%) spastic diplegic, five (2.7%) spastic monoplegic, 12 (5.5%) mixed, 12 (5.5%) ataxic-hypotonic, two (0.9%) dyskinetic, two (0.9%) Worster-Drought syndrome. Overall etiologic yield was 82.0%, varying according to type of cerebral palsy: 50% dyskinetic, 59% diplegia, 80% monoplegia, 80.9% hemiplegia, 90.9% quadriplegia, 91.7% ataxic hypotonia, and 100% mixed/Woster-Drought. The top five etiologic entities identified were periventricular leukomalacia, 24.9%; intrapartum asphyxia, 21.7%; cerebral dysgenesis, 17.1%; intracranial hemorrhage, 12.9%; and vascular, 9.7%. Although a single etiology was apparent in 144 (66.4%) of the cases, multiple etiologies were believed to be contributory in 34 (15.6%) of the cases. The etiologic profile varied according to such features as the type of cerebral palsy, gestational age, and the source (high-risk neonatal population or not) of the patients. Features of the child's cerebral palsy, such as microcephaly, neonatal difficulties, prior or coexisting epilepsy, and high-risk source, were found to be predictive of eventual etiologic yield. This contemporary evaluation of cerebral palsy etiologic yield suggests that it is much higher than previously reported and varies, depending on key clinical features.
The proportion of children with attention-deficit-hyperactivity disorder and epileptiform abnormalities is compared with an historic control group of normal school-aged children. The medical records of 655 children 5-16 years of age referred to a single pediatric neurologist (M.S.) from January 1991 to December 1999 with school problems, behavior problems, or hyperactivity were retrospectively reviewed. Clinical criteria for attention-deficit-hyperactivity disorder were satisfied in 476 of these children. An electroencephalogram was obtained from 347 patients and coded as epileptiform in 6.1 +/- 1.3%, which is significantly higher (chi-square test, P < 0.025) than the prevalence rate of 3.5 +/- 0.6% observed in a study of 3,726 normal school-aged children. The epileptiform abnormality was present only with activation procedures in six of our patients (hyperventilation [n = 2] and photic stimulation [n = 4]). Only three of the 21 children with epileptiform abnormalities developed a seizure disorder in our cohort. We conclude that the prevalence rate of epileptiform abnormalities is greater in children with attention-deficit-hyperactivity disorder compared with that observed in normal school-aged children when hyperventilation and photic stimulation are used. However, the clinical utility of routine electroencephalography in the diagnosis of a comorbid seizure disorder in children with attention-deficit-hyperactivity disorder is limited.
Meralgia paresthetica is a focal peripheral neuropathy involving the lateral femoral cutaneous nerve and is rarely observed in pediatric practice. Previous reports have highlighted its occurrence within the context of a regional bony malignancy. We present here three patients less than 18 years of age with idiopathic meralgia paresthetica.
Migraine equivalents of infancy, childhood, and adolescence are recognized periodic, paroxysmal syndromes without associated headache that are thought to be migrainous in etiology. Five such equivalents are presently recognized. Their clinical features and relative frequency in ambulatory pediatric neurology practice have not been well documented. Utilizing a comprehensive, standardized computer database, the occurrence of these migraine equivalents in a single pediatric neurology practice together with their observed clinical features were documented over an 8-year period. Of a total of 5,848 patients in the database, of whom 1,106 were migraineurs, 108 patients (1.8% of total, 9.8% of migraineurs) were identified to have migraine equivalents. The following distribution among migraine equivalents was observed: benign paroxysmal torticollis 11 (10.2% of patients with migraine equivalents), benign paroxysmal vertigo 41 (38%), abdominal migraine/cyclical vomiting 20 (18.5%), acephalgic migraine 31 (28.7%), and acute confusional migraine 5 (4.6%). In each type, with the exception of benign paroxysmal torticollis and acute confusional migraine, females clearly predominated, and in all types a strong positive family history of migraine was elicited (68%-100%). There was variation in the age of onset of a particular equivalent with considerable overlap observed. Coexisting more typical migraines were observed in from 10% (benign paroxysmal torticollis) to 70% (abdominal migraines/cyclical vomiting) of the cases. In conclusion, pediatric migraine equivalents occur with relative frequency in ambulatory practice, possessing discrete clinical features that have a clear relationship to more typical migrainous phenomena.
Chronic childhood neuropathies are predominantly hereditary in origin. Specific distinct clinical entities have been described, however, occasionally children with an unusual clinical phenotype are encountered in practice. We describe four children (3 males, 1 female) of Lebanese Moslem descent all sharing a common great-great-grandparent pairing with such a novel clinical spectrum. The three males were first cousins, each the product of a different parental consanguineous (i.e., parents second cousins) mating, whereas the female was a third cousin to each of the males whose parents were also second cousins. Each child presented early in life with developmental delay with associated hypotonia and areflexia. All had a sensorineural hearing loss documented and two of the patients were dysmorphic in facial appearance. Nerve conduction studies highlighted a sensory axonal neuropathy and sural nerve biopsy undertaken in two patients confirmed an axonal neuropathy. Detailed genetic and metabolic testing was negative. Followed into later childhood, each child continued to manifest motoric impairment, unsteadiness, areflexia, and cognitive disability. These children appear to provide evidence for a novel autosomal recessive inherited chronic predominantly sensory neuropathy that shares core clinical features with observed variability in associated symptoms.
The ethical conduct of clinical research in children is challenged by the inherent vulnerability of this population. Children are both incompetent decision makers and have a right to custody (ie, protection), yet they must also be participants in research that will advance the care of pediatric disorders or they risk becoming "therapeutic ophans." Consensus guidelines exist for the conduct of clinical research in children. Aspects of consent, risk-benefit ratios, fair subject selection, and respect for subjects have child-specific concerns. It is only by explicitly recognizing and addressing these child-specific concerns can the conduct of pediatric clinical research achieve and maintain a high level of ethical propriety.
Medical futility concerns itself with decisions regarding treatments that are of minimal potential benefit to the patient. The concept of futility has evolved with the practice of medicine and consensus has been elusive. Presently, most typically, futility is conceptualized quantitatively as overwhelming improbability in the face of possibility, and qualitatively as an outcome that although achievable is overwhelmingly poor from the patient's perspective. Though frequently intermixed, futility and rationing are separate matters, with futility reflecting individual decisions taken at the bedside, whereas rationing represents decisions of publicly determined health policy. Objective, uniformly applicable guidelines regarding futility will likely be difficult to achieve and thus local efforts must be focused on implementing mechanisms to minimize and resolve inevitable disputes between patients, families, and caregivers.
OBJECTIVES: To determine the prevalence of persistent developmental impairments in children with congenital heart defects and to identify factors that enhance risk for an adverse outcome. STUDY DESIGN: Eligible infants (n = 131) <2 years of age requiring open heart surgery were recruited prospectively. Subjects were assessed during surgery and again 12 to 18 months later with standardized developmental assessments and formal neurologic examinations. RESULTS: Mean age at follow-up testing was 19.1 +/- 6.6 months. Assessments indicated that 41% had abnormal neurologic examinations. Gross and/or fine motor delays were documented in 42%, and 23% demonstrated global developmental delay. Univariate and multiple regression models identified the following factors increasing the risk for persistent developmental deficits: preoperative and acute postoperative neurodevelopmental status and microcephaly, type of heart lesion, length of deep hypothermic circulatory arrest, age at surgery, and days in the intensive care unit (P <.05). CONCLUSIONS: Children with congenital heart defects commonly have ongoing neurologic, motor, and developmental deficits well after surgical correction. The cause is multifactorial and includes brain injury before, during, and after heart surgery.
This study reports the clinical profile, etiologies identified, and outcomes for a consecutive series of children with partial or complete agenesis of the corpus callosum. Children with agenesis of the corpus callosum were identified in a comprehensive computerized database of all patients seen in a single pediatric neurology practice over an 11-year interval. Medical records were then systematically reviewed. Twenty-four children with agenesis of the corpus callosum were identified of a total of 6911 children in the database (0.35%). Fifteen were male (62.5%); 9 (37.5%) had presented antenatally, 6 (25%) neonatally, and 9 (37.5%) postneonatally. Eight (33.3%) were microcephalic, 12 (50%) were dysmorphic, 11 (45.8%) had coexisting epilepsy, and 9 (37.5%) had a cerebral palsy variant. Investigations revealed an etiology in 11 (45.8%): 3 chromosomal abnormality, 3 metabolic disorder, 3 cerebral dysgenesis, and 2 genetic syndromes (Aicardi, Andermann). Outcomes identified included normal or mild developmental delay in 7 (29.2%) and moderate-severe developmental delay in the remaining 17 (70.8%). Factors predictive of successful etiologic determination on bivariate analysis included moderate-severe developmental delay or associated cerebral dysgenesis. Factors predictive of eventual developmental outcome included microcephaly, coexisting epilepsy, cerebral palsy, or cerebral dysgenesis. A spectrum of clinical presentations, underlying etiology, and developmental outcome is thus apparent in children with agenesis of the corpus callosum. An underlying etiology can be identified in slightly less than half of cases, and a normal or mildly delayed outcome is apparent in slightly less than a third. Factors predictive of identifying an underlying etiology or eventual outcome can be identified.
The objective of this study was to compare the clinical and electroencephalographic features of two groups of children with benign epilepsy of childhood with rolandic spikes: those in whom seizure control was attained either without the use of medication or with a single medication (group 1) and those requiring two medications for seizure control (group 2). A consecutive series of children with benign epilepsy of childhood with rolandic spikes was identified in a single pediatric neurology practice. Medical charts were then systematically retrospectively reviewed. A total of 66 children with benign epilepsy of childhood with rolandic spikes was identified; 52 (78.8%) required either no medication (n = 7) or a single medication (n = 45) for seizure control, whereas 14 (21.2%) required two medications. The two groups did not differ with respect to gender, age of onset, type (generalized or partial) of initial seizure, or whether EEG abnormalities were unilateral or bilateral. They did differ significantly with respect to the mean number of seizures experienced prior to initiating treatment (group 1, 2.06, versus group 2, 4.36; t = 3.40, P = .005). In those treated (n = 59), the initial medication selected (carbamazepine versus noncarbamazepine) in the two groups was significantly different: group 1, 40 (carbamazepine)/45, versus group 2, 9 (carbamazepine)/14; chi2 = 4.59; P = .03. The difference in frequency between the two groups of associated comorbid conditions (tics, attention-deficit hyperactivity disorder [ADHD], learning disability) almost reached the threshold of statistical significance: group 1, 7/52, versus group 2, 5/14 (chi2 = 3.67, P = .06). A subset of children with benign epilepsy of childhood with rolandic spikes may require more than one medication for effective seizure control. This subset experiences more seizures prior to the initiation of treatment, is more likely to be treated initially with a noncarbamazepine medication, and tends to have a higher frequency of associated conditions.