Biomedical subjects

L G Vezina

Publications and source records attributed to L G Vezina.

At least 19 recordsLinked to original sources

PubMed2004

fMRI language task panel improves determination of language dominance.

BACKGROUND: fMRI language tasks reliably identify language areas in presurgical epilepsy patients, but activation using single paradigms may disagree with the intracarotid amobarbital test (IAT). OBJECTIVE: To determine whether a panel of fMRI tasks targeting different aspects of language processing increases accuracy in determining hemisphere language dominance. METHODS: Twenty-six patients age 12 to 56 years, predominantly with temporal lobe epilepsy, were studied using whole-brain 1.5 T fMRI (echo planar imaging, blood oxygenation level-dependent) with three task categories using a block design: verbal fluency, reading comprehension, and auditory comprehension. fMRI t maps were visually rated at three thresholds. All patients had assessment of language lateralization by IAT. RESULTS: fMRI showed left dominance in 21 patients, right dominance in 2, and bilateral activation in 2; raters disagreed over a left vs right bilateral rating in 1 patient. There was full agreement between IAT and fMRI in 21 of 25 patients (IAT failed in 1). In three instances of partial disparity with IAT, the fMRI panel showed consistent findings across raters. Agreement between raters was excellent (partial disagreement in only one patient); the panel of tasks was superior to any single task for interrater agreement (Cramer V 0.93 [range 0.91 to 1.0] vs 0.72 [range 0.60 to 0.86]). CONCLUSIONS: A panel of fMRI language paradigms may be more accurate for evaluating partial epilepsy patients than a single task. A panel of tasks reduces the likelihood of nondiagnostic findings, improves interrater reliability, and helps confirm language laterality.

Adolescent↗

PubMed2003

Clinical spectrum of succinic semialdehyde dehydrogenase deficiency.

Succinic semialdehyde dehydrogenase (SSADH) deficiency is a rare autosomal recessive disorder affecting CNS gamma-aminobutyric acid (GABA) degradation. SSADH, in conjunction with GABA transaminase, converts GABA to succinate. In the absence of SSADH, GABA is converted to 4-OH-butyrate. The presence of 4-OH-butyrate, a highly volatile compound, may be undetected on routine organic acid analysis. Urine organic acid testing was modified at the authors' institution in 1999 to screen for the excretion of 4-OH-butyrate by selective ion monitoring gas chromatography-mass spectrometry in addition to total ion chromatography. Since then, five patients with 4-hydroxybutyric aciduria have been identified. The authors add the clinical, neuroimaging, and EEG findings from a new cohort of patients to 51 patients reported in the literature with clinical details. Ages ranged from 1 to 21 years at diagnosis. Clinical findings include mild-moderate mental retardation, disproportionate language dysfunction, hypotonia, hyporeflexia, autistic behaviors, seizures, and hallucinations. Brain MRI performed in five patients at the authors' institution revealed symmetric increased T2 signal in the globus pallidi. SSADH deficiency is an under-recognized, potentially manageable neurometabolic disorder. Urine organic acid analysis should include a sensitive method for the detection of 4-hydroxybutyrate and should be obtained from patients with mental retardation or neuropsychiatric disturbance of unknown etiology.

Adolescent↗

PubMed2002

Language dominance in partial epilepsy patients identified with an fMRI reading task.

BACKGROUND: fMRI language tasks readily identify frontal language areas; temporal activation has been less consistent. No studies have compared clinical visual judgment to quantitative region of interest (ROI) analysis. OBJECTIVE: To identify temporal language areas in patients with partial epilepsy using a reading paradigm with clinical and ROI interpretation. METHODS: Thirty patients with temporal lobe epilepsy, aged 8 to 56 years, had 1.5-T fMRI. Patients silently named an object described by a sentence compared to a visual control. Data were analyzed with ROI analysis from t-maps. Regional asymmetry indices (AI) were calculated ([L-R]/[L+R]) and language dominance defined as >0.20. t-Maps were visually rated by three readers at three t thresholds. Twenty-one patients had intracarotid amobarbital test (IAT). RESULTS: The fMRI reading task provided evidence of language lateralization in 27 of 30 patients with ROI analysis. Twenty-five were left dominant, two right, one bilateral, and two were nondiagnostic; IAT and fMRI agreed in most patients, three had partial agreement, none overtly disagreed. Interrater agreement ranged between 0.77 to 0.82 (Cramer V; p < 0.0001); agreement between visual and ROI reading with IAT was 0.71 to 0.77 (Cramer V; p < 0.0001). Viewing data at lower thresholds added interpretation to 12 patients on visual analysis and 8 with ROI analysis. CONCLUSIONS: An fMRI reading paradigm can identify language dominance in frontal and temporal areas. Clinical visual interpretation is comparable to quantitative ROI analysis.

Adolescent↗

PubMed2000

Neurodevelopmental and neuroimaging correlates in nonsyndromal microcephalic children.

This descriptive study examined the relationship between head size, developmental functioning, and neuroimaging findings in children with absolute microcephaly. Subjects, aged 1 to 48 months, were assigned to one of two groups based on occipitofrontal head circumference (OFC). Group A included subjects with an OFC of 2 to 2.99 standard deviations below the mean, and Group B included subjects with an OFC of 3 or more standard deviations below the mean. Brain scan findings for 62% of the subjects were abnormal. Findings included cerebral atrophy, cortical dysplasia, myelination delay, and white matter hypoplasia. Mean scores for developmental measures in Groups A and B were less than 70. Mean developmental scores in the normal imaging group were 70 or greater, whereas developmental scores in the abnormal imaging group were 52 or less. Forty-three percent of the subjects in Group A and 80% of those in Group B had abnormal findings from imaging studies (p = .0394). Subjects with one or more brain abnormalities determined on the basis of magnetic resonance images or computed tomographic scans had significantly lower scores in all developmental areas (p < .05). The authors concluded that abnormal brain images seem to be a better reflection of developmental performance than the degree of microcephaly. J Dev Behav Pediatr 21:12-18, 2000. Index terms: microcephaly, neuroimaging, neurodevelopment.

Anthropometry↗

PubMed2000

Spontaneous regression of low-grade astrocytomas in childhood.

An 8-year-old boy with neurofibromatosis type 1 (NF1) and a biopsy-proven juvenile pilocytic astrocytoma of the hypothalamic/chiasmatic region was followed with serial MRIs over 4 years. Spontaneous tumor regression was followed by progression and biopsy; 6 months later, the tumor regressed again. This bimodal regression is rare, but highlights the variable natural history of low-grade gliomas in children with NF1 and the difficulty in evaluating response of such tumors to therapy.

Astrocytoma↗

PubMed2000

Imaging and clinical evaluation of isolated atresia of the oval window.

BACKGROUND AND PURPOSE: Congenital causes of hearing loss in children commonly are encountered, and imaging aids in diagnosis as well as presurgical evaluation. Atresia of the oval window not associated with atresia of the external auditory canal (EAC) is a rare cause of congenital hearing loss in children. We present the clinical and imaging findings in children with isolated oval-window atresia. METHODS: Atresia of the oval window was defined as the absence of the structure with the presence of a bony plate superimposed between the vestibule and middle ear. The bony plate is within the expected region of the oval window. Using a computerized database, nine patients with isolated oval-window atresia were found. All had been evaluated with high-resolution computed tomography (HRCT) and all had medical records available for review, including audiogram results. Imaging studies were interpreted by the consensus of two pediatric neuroradiologists. RESULTS: Atresia of the oval window was documented in all cases using HRCT criteria. The most common anomalies associated with oval-window atresia were inferomedial malposition of the facial nerve (n = 8), malformed incus (n = 6), and displaced stapes (n = 2). Four patients had symmetric bilateral involvement. Hearing tests were not specific, because conductive, sensorineural, and mixed patterns were found. CONCLUSION: Anomalies of the oval window should be sought in all patients with congenital hearing loss. Associated findings, such as facial nerve aberrancy and ossicular anomalies, are important in both diagnosis and surgical planning.

Adolescent↗

PubMed2000

Acute identification of cranial burst fracture: comparison between CT and MR imaging findings.

BACKGROUND AND PURPOSE: Scalp swelling associated with cranial burst fracture, a widely diastatic skull fracture of infants associated with dural laceration and acute cerebral extrusion, may be confused with that of a simple subgaleal hematoma. Both conditions can also be associated with hemorrhagic shock. We sought to improve the early evaluation of infants believed to have sustained cranial burst fracture by including MR imaging, since this study clearly delineates the dural-cortical interface, the site of injury. METHODS: Seven infants aged 1 through 11 months who sustained cranial burst fractures, all initially imaged with skull radiography and CT, were studied or treated from 1992 through 1996. MR imaging was obtained after resuscitation and stabilization. RESULTS: Surgery or autopsy confirmed MR findings (dural laceration and extracalvarial cerebral tissue) in all seven infants. CONCLUSION: MR imaging allows early diagnosis of skull fracture associated with acute cerebral extrusion.

Brain Edema↗

PubMed1999

Stroke after zoster ophthalmicus in a 12-year-old girl with protein C deficiency.

A 12-year-old girl who had zoster ophthalmicus 10 months earlier presented with hemiparesis and corresponding basal ganglionic infarction related to middle cerebral artery branch thrombosis ipsilateral to the zoster. Hematologic evaluation disclosed protein C deficiency. This represents the first zoster-associated stroke reported in childhood associated with protein C deficiency, with extension of the latency period between zoster and infarction, previously reported to be 6 months.

Brain↗

PubMed1999

Treatment of children with medulloblastomas with reduced-dose craniospinal radiation therapy and adjuvant chemotherapy: A Children's Cancer Group Study.

PURPOSE: Medulloblastoma is the most common malignant brain tumor of childhood. After treatment with surgery and radiation therapy, approximately 60% of children with medulloblastoma are alive and free of progressive disease 5 years after diagnosis, but many have significant neurocognitive sequelae. This study was undertaken to determine the feasibility and efficacy of treating children with nondisseminated medulloblastoma with reduced-dose craniospinal radiotherapy plus adjuvant chemotherapy. PATIENTS AND METHODS: Over a 3-year period, 65 children between 3 and 10 years of age with nondisseminated medulloblastoma were treated with postoperative, reduced-dose craniospinal radiation therapy (23.4 Gy) and 55.8 Gy of local radiation therapy. Adjuvant vincristine chemotherapy was administered during radiotherapy, and lomustine, vincristine, and cisplatin chemotherapy was administered during and after radiation. RESULTS: Progression-free survival was 86% +/- 4% at 3 years and 79% +/- 7% at 5 years. Sites of relapse for the 14 patients who developed progressive disease included the local tumor site alone in two patients, local tumor site and disseminated disease in nine, and nonprimary sites in three. Brainstem involvement did not adversely affect outcome. Therapy was relatively well tolerated; however, the dose of cisplatin had to be modified in more than 50% of patients before the completion of treatment. One child died of pneumonitis and sepsis during treatment. CONCLUSION: These overall survival rates compare favorably to those obtained in studies using full-dose radiation therapy alone or radiation therapy plus chemotherapy. The results suggest that reduced-dose craniospinal radiation therapy and adjuvant chemotherapy during and after radiation is a feasible approach for children with nondisseminated medulloblastoma.

Antineoplastic Combined Chemotherapy Protocols↗

PubMed1998

Treatment of diencephalic syndrome with chemotherapy: growth, tumor response, and long term control.

BACKGROUND: The diencephalic syndrome (DS), which is manifested by progressive emaciation and failure to thrive in an apparently alert, cheerful infant, usually is due to a low grade hypothalamic glioma. Treatment with aggressive surgery and/or radiotherapy is variably successful in controlling disease and may result in severe neurologic sequelae. Chemotherapy recently has been shown to be effective in patients with low grade gliomas of childhood, but it is used infrequently in those with DS. METHODS: The authors evaluated the efficacy of a regimen of carboplatin and vincristine on improving weight, causing tumor shrinkage, and delaying the need for alternative therapies in seven children (ages 9-20 months; median age, 11 months) with DS. Five patients weighed less than the 5th percentile for their age at the start of the study, one weighed within the 10th percentile, and one weighed within the 25th percentile. RESULTS: At follow-up (range, 6-54 months; median, 28 months), the patients' weights had increased by 66-95% (median, 80%). On magnetic resonance imaging, four patients had a >50% reduction in tumor mass, one had a 25-50% reduction, and two had stable disease. In those patients with radiographic response to treatment, weight gain was accomplished with oral feedings in four of five patients, whereas those with stable disease required nasogastric, nasojejunal, or gastrostomy tube supplementation to maintain weight. Disease progression occurred at a median of 24 months after initiation of chemotherapy, and two patients remained free of progressive disease at last follow-up. Five patients were alive a median of 59 months from diagnosis. The need for radiation or other therapies was delayed in six of seven children. Therapy was tolerated without significant toxicities. CONCLUSION: The authors conclude that treatment of DS with a carboplatin and vincristine regimen results in demonstrable weight gain, may result in tumor shrinkage, and in some cases, significantly delays the need for alternative therapies.

Antineoplastic Combined Chemotherapy Protocols↗

PubMed1998

Emergency brain computed tomography in children with seizures: who is most likely to benefit?

OBJECTIVE: To determine whether the recently published guidelines on neuroimaging in patients with new-onset seizures are applicable to children. METHODS: We carried out a retrospective analysis of 107 neurologically normal children (excluding children with simple febrile seizures) who had undergone neuroimaging when they presented to the emergency department with a possible "first seizure." RESULTS: Eight of the 107 children had nonepileptic events (gastroesophageal reflux, syncopal event, rigor). Of the remaining 99 children, 49 had provoked seizures (complicated febrile seizure, meningo-encephalitis, toxic or metabolic abnormalities), and 50 had unprovoked seizures. A total of 19 children had brain abnormalities identified on computed tomography (CT) scan; 7 received further investigation or intervention as a result of CT scan findings (2 with tumors, 3 with vascular anomalies, 1 with cysticercosis, and 1 with obstructive hydrocephalus). CT scan abnormalities requiring treatment or monitoring were more frequently seen in children with their first unprovoked seizure (P < .01) and in those children whose seizure onset had been focal or who had focal abnormalities identified on postictal neurologic examination (P < .04). CONCLUSION: In a child, a seizure in the setting of a fever rarely indicates the presence of an unexpected CT scan lesion requiring intervention.

Adolescent↗

PubMed1998

Phase I study of temozolomide in children and adolescents with recurrent solid tumors: a report from the Children's Cancer Group.

PURPOSE: The Children's Cancer Group conducted a phase I trial of temozolomide stratified by prior craniospinal irradiation (CSI). PATIENTS AND METHODS: Children and adolescents with recurrent or progressive cancer were enrolled. Temozolomide was administered orally daily for 5 days, with subsequent courses administered every 21 to 28 days after full hematologic recovery. Dose levels tested included 100, 150, 180, 215, 245, and 260 mg/m2 daily. RESULTS: Twenty-seven patients on the non-CSI stratum were assessable for hematologic toxicity. During the first three dose levels (100, 150, and 180 mg/m2 daily), only grades 1 and 2 hematologic toxicity occurred. One patient at 215 mg/m2 daily had grade 3 hematologic toxicity. Three of eight patients (38%) treated at 245 to 260 mg/m2 daily had dose-limiting toxicity (DLT), which included both neutropenia and thrombocytopenia. Twenty-two patients on the CSI stratum were assessable for hematologic toxicity. Hematologic DLT occurred in one of six patients (17%) at 100 mg/m2 daily and in two of four patients (50%) at 215 mg/m2 daily. No nonhematologic DLT occurred; nausea and vomiting occurred in more than half of the patients. After two courses of temozolomide, 10 patients had stable disease (SD), and three patients had a partial response (PR), one of whom subsequently had a complete response (CR) that persists through 24 months of follow-up. CONCLUSION: The maximum-tolerated dose (MTD) of temozolomide for children and adolescents without prior CSI is 215 mg/m2 daily and for those with prior CSI is 180 mg/m2 daily for 5 days, with subsequent courses that begin on day 28. Temozolomide is well tolerated and should undergo phase II testing in children and adolescents.

Adolescent↗

PubMed1997

Relative incidence and alternative approaches for surgical drainage of different types of deep neck abscesses in children.

OBJECTIVES: To determine the relative frequency of retropharyngeal abscesses (RPAs) vs lateral pharyngeal abscesses (LPAs) and to analyze alternative approaches for surgical drainage. DESIGN: Retrospective chart review. SETTING: Tertiary care children's hospital. PATIENTS: Seventy pediatric patients who were evaluated, admitted, and treated for presumed deep neck abscesses (RPAs and LPAs) between January 1, 1986, and December 31, 1996. INTERVENTION: Intravenous antibiotic therapy and surgical drainage. MAIN OUTCOME MEASURE: Clinical resolution of the abscess. RESULTS: Fifty-eight patients were evaluated with computed tomographic scan. Thirteen of these patients did not have surgical intervention. Of 12 patients diagnosed as having an isolated RPA, all had intraoral surgical drainage and 9 had evidence of pus at surgery. Twenty-one patients had an isolated LPA. Sixteen of these underwent intraoral drainage and 5 underwent external drainage. Purulence was found at surgery in 14 and 2 patients, respectively. The remaining 12 patients had a combination of RPA and LPA. Eight patients underwent intraoral drainage, and 4 patients required both intraoral and external approaches. Purulence was found at surgery in 5 and 4 patients, respectively. Of the 12 patients who were not evaluated with computed tomographic scan, two thirds were treated prior to 1987. Six of these 12 patients underwent surgical drainage via an intraoral approach, and 4 of the 6 patients had pus. The remaining 6 improved without surgery. CONCLUSIONS: Most deep neck abscesses in children are located in the retropharyngeal or in the lateral pharyngeal space medial to the great vessels. Therefore, most can be managed successfully with intraoral rather than external drainage. External approaches are better reserved for those abscesses that are lateral to the great vessels or that involve multiple spaces. In this patient population, LPAs were more commonly seen than RPAs.

Abscess↗

PubMed1997

Diagnostic imaging in neuro-oncology.

Recent advances in imaging techniques, biologic characterization, and histologic classification have contributed to improving management of children with brain tumors. The overall prognosis of children with brain tumors nevertheless lags behind that of other pediatric oncologic diseases. This article reviews recent developments in tumor imaging.

Brain Neoplasms↗

PubMed1997

Pediatric congenital bilateral perisylvian syndrome: clinical and MRI features in 12 patients.

In 1926, Foix, Chavany and Marie described an acquired syndrome of fasciopharyngoglossomasticatory diplegia resulting from bilateral infarction of the anterior operculum. Clinical features consisted of facial diplegia, dysarthria, pseudobulbar palsy, mild to severe mental retardation, and seizures. A developmental form, similar in presentation in adults with MRI findings consisting of bilateral perisylvian cortical malformation consistent with polymicrogyria involving the sylvian fissure and opercular cortex, has been recognized; but few pediatric cases of congenital bilateral perisylvian syndrome (CBPS) have been reported. Over the past four years, we have encountered 12 cases of CBPS presenting in childhood. Age ranges were from 1 week to 11 years with a median of 2.25 years; six were less than two years of age. Seven were male and five female. Ten had bilateral perisylvian polymicrogyria on MRI; two had unilateral perisylvian schizencephaly with contralateral perisylvian polymicrogyria. Clinical manifestations included developmental delay in 7; poor palatal function in 5; hypotonia in 4; arthrogryposis in 4; hemiparesis in 3; apnea in 3; paraparesis in 2; micrognathia in 2; pectus excavatum in 2; quadriparesis in 1; and hearing loss in 1. Seizures occurred in seven (58%) and consisted of infantile spasms (n = 1), generalized tonic-clonic (n = 1), complex partial (n = 2), partial motor (n = 2; 1 with secondary generalization), and febrile convulsions (n = 1). CBPS has different manifestations in the pediatric population than in adults. CBPS is more common than previously thought, is recognizable by MRI and should be suspected clinically in any infant or child presenting with oromotor dysfunction/pseudobulbar signs and developmental delay, especially if there are associated congenital malformations. Epilepsy is not a constant feature in the pediatric presentation and is variable in type and severity.

Abnormalities, Multiple↗

PubMed1996

Treatment of children with newly diagnosed brain stem gliomas with intravenous recombinant beta-interferon and hyperfractionated radiation therapy: a childrens cancer group phase I/II study.

BACKGROUND: Prognosis for the majority of children with brain stem gliomas is dismal. In previous studies, recombinant beta-interferon (r beta IF) has been shown to be effective for children with recurrent brain stem gliomas and may also act synergistically with radiotherapy (RT). METHODS: Thirty-two children with diffuse intrinsic brain stem gliomas were treated with (r beta IF) and 7200 centigray (cGy) of hyperfractionated RT (100 cGy twice-daily fractions) to determine the toxicity of treatment and the tolerance of the brain stem to this regimen, as well as to assess survival. Patients were treated with r beta IF 3 times per week during RT and then for 8 weeks following RT. Initially, a dose escalation trial was performed. RESULTS: Interferon was initially begun at 12.5 x 10(6) IU/m2 and escalated up to 400 x 10(6) IU/m2. The safe starting dose was determined to be 100 x 10 (6) IU/m2. Due to unacceptable toxicity, the maintenance dose was reduced to 200 x 10 (6) IU/m2. Therapy was relatively well tolerated, although 13 of the patients required dose modifications due to hepatic or hematologic toxicity. Four of the patients had to discontinue treatment due to this toxicity. One patient died while receiving maintenance IF of encephalopathy, seizures, and brain stem dysfunction; believed possibly due to the r beta IF. Thirty of the 32 patients have developed progressive disease. The median time to progression from study entry was five months and the median time to death was 9 months. CONCLUSIONS: We conclude that r beta IF plus hyperfractionated therapy can be tolerated by children with newly diagnosed brain stem gliomas, although there is occasional dose-limiting hepatic, blood, and central nervous system toxicity. This therapy did not result in a higher rate of disease control.

Adolescent↗

PubMed1995

Patient with craniosynostosis and marfanoid phenotype (Shprintzen-Goldberg syndrome) and cloverleaf skull.

Marfanoid phenotype with craniosynostosis (Shprintzen-Goldberg syndrome) is a rare disorder previously described in only 5 patients. We report on the sixth known patient with this condition. The findings which distinguish our patient from others reported previously are that she was ascertained prenatally as having a cloverleaf skull; this is the first female patient described with this condition. Postnatally, she presented with arachnodactyly, camptodactyly, and clover-leaf skull. Imaging studies of the brain documented microcephaly with malformed brain, hydrocephaly, and hypoplasia of the corpus callosum. She also had choanal atresia and stenosis, a clinical finding previously reported only once, in this disorder.

Abnormalities, Multiple↗

PubMed1995

Enlarged vestibular aqueduct and sensorineural hearing loss in childhood.

OBJECTIVE: To determine if all children with enlarged vestibular aqueducts (EVAs) have development of uniform progressive sensorineural hearing loss (SNHL). To determine whether the size of the EVA correlates with severity, frequencies involved, and stability of SNHL. To determine if the audiologic pattern of SNHL correlates with likelihood of progression of SNHL. DESIGN: Retrospective study. SETTING: Children's National Medical Center, Washington, DC, a tertiary care center with a large otologic practice. PATIENTS: Fifteen children (26 ears) with EVA on computed tomographic scan. METHODS: History, physical examination, computed tomographic scans, and serial audiograms were reviewed. Factors analyzed included age at diagnosis, audiometric configuration (high tone, midtone, low tone, flat), degree of hearing loss at presentation, length of follow-up, and presence of associated inner ear anomalies. RESULTS: Nine ears had progressive SNHL, 16 ears had stable SNHL, and 1 ear had profound SNHL. The predominant audiologic configuration was flat. The audiogram configuration does not correlate with progression of SNHL. The size of the vestibular aqueduct does not correlate with the level, type, or progression of SNHL. CONCLUSION: Our study failed to uncover factors that might be predictive of progression of hearing loss. We conclude that until a better understanding of the natural history and pathophysiologic condition of EVAs is achieved, there is no surgical or other intervention that can be demonstrated as being efficacious.

Audiometry↗