Early Treatment with Vigabatrin Does Not Decrease Focal Seizures or Improve Cognition in Tuberous Sclerosis Complex: The PREVeNT Trial

OBJECTIVE

This study was undertaken to test the hypothesis that early vigabatrin treatment in tuberous sclerosis complex (TSC) infants improves neurocognitive outcome at 24 months of age.

METHODS

A phase IIb multicenter randomized double-blind placebo-controlled trial was conducted of vigabatrin at first epileptiform electroencephalogram (EEG) versus vigabatrin at seizure onset in infants with TSC. Primary outcome was Bayley Scales of Infant and Toddler Development, Third Edition (Bayley-III) cognitive assessment score at 24 months. Secondary outcomes were prevalence of drug-resistant epilepsy, additional developmental outcomes, and safety of vigabatrin.

RESULTS

Of 84 infants enrolled, 12 were screen failures, 4 went straight to open label vigabatrin, and 12 were not randomized (normal EEG throughout). Fifty-six were randomized to early vigabatrin (n = 29) or placebo (n = 27). Nineteen of 27 in the placebo arm transitioned to open label vigabatrin, with a median delay of 44 days after randomization. Bayley-III cognitive composite scores at 24 months were similar for participants randomized to vigabatrin or placebo. Additionally, no significant differences were found between groups in overall epilepsy incidence and drug-resistant epilepsy at 24 months, time to first seizure after randomization, and secondary developmental outcomes. Incidence of infantile spasms was lower and time to spasms after randomization was later in the vigabatrin group. Adverse events were similar across groups.

INTERPRETATION

Preventative treatment with vigabatrin based on EEG epileptiform activity prior to seizure onset does not improve neurocognitive outcome at 24 months in TSC children, nor does it delay onset or lower the incidence of focal seizures and drug-resistant epilepsy at 24 months. Preventative vigabatrin was associated with later time to onset and lower incidence of infantile spasms. ANN NEUROL 2023.

Longitudinal impact of cannabidiol on EEG measures in subjects with treatment-resistant epilepsy

OBJECTIVE

To assess the longitudinal impact of highly purified cannabidiol (CBD) on the electroencephalogram (EEG) of children and adults.

METHODS

Participants received an EEG prior to starting CBD, after approximately 12 weeks of CBD (FU1) and after approximately one year of CBD therapy (FU2). Longitudinal changes in five EEG measures (background frequency, focal slowing, reactivity, frequency of interictal, and ictal discharges) were examined following CBD exposure. Data were compared between pediatric and adult groups at two follow-up time points and within groups over time. Population-averaged models with generalized estimation equations or linear mixed effects models were used to analyze data where appropriate. Correlation analysis was used to assess any association between changes in seizure frequency and changes in EEG interictal discharge (IED) frequency. An alpha level of 5% was used to assess statistical significance.

RESULTS

At FU1, the adult group showed significant decrease in IED/minute (IDR 0.07, 95% CI [0.04, 0.14], P < 0.001); a nonsignificant decrease was observed among children (IDR 0.87, 95% CI [0.47, 0.64], P = 0.67). The difference in changes over time between participant groups was significant after adjusting for last CBD dose (IDR 11.8, 95% CI [4.86, 28.65], P < 0.0001). At FU2 both groups showed significant reduction from baseline after controlling for last CBD dose. This decrease was more pronounced in children (IDR 15.38, 95% CI [4.93, 47.99], P < 0.001). There was no significant correlation between changes in seizure frequency and EEG IED frequency at each timepoint (P = 0.542, 0.917 and 0.989 from baseline to FU1, FU1 to FU2 and baseline to FU2, respectively).

SIGNIFICANCE

This longitudinal EEG study shows that highly-purified plant-derived CBD has positive effects on interictal epileptiform discharge frequency but no effects on other EEG measures. The effect of CBD does not appear to be dose or treatment-duration dependent.

White matter integrity after cannabidiol administration for treatment resistant epilepsy

OBJECTIVE

The effects of individual cannabinoids on white matter integrity are unclear. Human studies have shown white matter maturation alterations in regular recreational cannabis users with the magnitude of these effects dependent on the age of exposure. However, studies have yet to determine which phytocannabinoids are most responsible for these changes. In the current study, we analyzed the effects of pharmaceutical grade cannabidiol oral solution (CBD; Epidiolex® in the U.S.; Epidyolex® in the EU; 100 mg/mL oral solution) on white matter integrity using diffusion MRI in patients with treatment resistant epilepsy (TRE).

METHODS

15 patients with TRE underwent 3 T diffusion MRI prior to receiving CBD and then again approximately 12 weeks later while on a stable dose of CBD for at least two weeks. DTI analyzes were conducted using DSI Studio and tract-based spatial statistics (TBSS).

RESULTS

DTI analysis using DSI Studio showed significant increases in fractional anisotropy (FA) in the right medial lemniscus (p = 0.03), right superior cerebellar peduncle (p = 0.03) and the pontine crossing tract (p = 0.04); decreased mean diffusivity (MD) in the left uncinate fasciculus (p = 0.02) and the middle cerebellar peduncle (p = 0.04); decreased axial diffusivity (AD) in the left superior cerebellar peduncle (p = 0.05), right anterior limb of the internal capsule (p = 0.03), and right posterior limb of the internal capsule (p = 0.02); and decreased radial diffusivity (RD) in the middle cerebellar peduncle (p = 0.03) and left uncinate fasiculus (p = 0.01). The follow-up ANCOVA also yielded significant results when controlling for covariates of CBD dosage, age, sex, change in seizure frequency, and scanner type: FA increased in the pontine crossing tract (p = 0.03); RD decreased in the middle cerebellar peduncle (p = 0.04) and left uncinate fasciculus (p = 0.04). Subsequent TBSS analysis controlling for the same variables yielded no significant white matter differences between groups.

CONCLUSION

These findings indicate relatively minor short-term effects of highly-purified plant-derived CBD on white matter structural integrity in patients with TRE.

Resting-State fMRI Networks in Children with Tuberous Sclerosis Complex

BACKGROUND AND PURPOSE

There are no published studies examining resting state networks (RSNs) and their relationship with neurodevelopmental metrics in tuberous sclerosis complex (TSC). We aimed to identify major resting-state functional magnetic resonance imaging (rs-fMRI) networks in infants with TSC and correlate network analyses with neurodevelopmental assessments, autism diagnosis, and seizure history.

METHODS

Rs-fMRI data from 34 infants with TSC, sedated with propofol during the scan, were analyzed to identify auditory, motor, and visual RSNs. We examined the correlations between auditory, motor, and visual RSNs at approximately 11.5 months, neurodevelopmental outcome at approximately 18.5 months, and diagnosis of autism spectrum disorders at approximately 36 months of age.

RESULTS

RSNs were obtained in 76.5% (26/34) of infants. We observed significant negative correlations between auditory RSN and auditory comprehension test scores (p = .038; r = -.435), as well as significant positive correlations between motor RSN and gross motor skills test scores (p = .023; r = .564). Significant positive correlations between motor RSNs and gross motor skills (p = .012; r = .754) were observed in TSC infants without autism, but not in TSC infants with autism, which could suggest altered motor processing. There were no significant differences in RSNs according to seizure history.

CONCLUSIONS

Negative correlation between auditory RSN, as well as positive correlation between motor RSN and developmental outcome measures might reflect different brain mechanisms and, when identified, may be helpful in predicting later function. A larger study of TSC patients with a healthy control group is needed before auditory and motor RSNs could be considered as neurodevelopmental outcome biomarkers.

Cannabidiol improves frequency and severity of seizures and reduces adverse events in an open-label add-on prospective study

The objective of this study was to characterize the changes in adverse events, seizure severity, and frequency in response to a pharmaceutical formulation of highly purified cannabidiol (CBD; Epidiolex®) in a large, prospective, single-center, open-label study. We initiated CBD in 72 children and 60 adults with treatment-resistant epilepsy (TRE) at 5 mg/kg/day and titrated it up to a maximum dosage of 50 mg/kg/day. At each visit, we monitored treatment adverse events with the adverse events profile (AEP), seizure severity using the Chalfont Seizure Severity Scale (CSSS), and seizure frequency (SF) using seizure calendars. We analyzed data for the enrollment and visits at 12, 24, and 48 weeks. We recorded AEP, CSSS, and SF at each follow-up visit for the weeks preceding the visit (seizures were averaged over 2-week periods). Of the 139 study participants in this ongoing study, at the time of analysis, 132 had 12-week, 88 had 24-week, and 61 had 48-week data. Study retention was 77% at one year. There were no significant differences between participants who contributed all 4 data points and those who contributed 2 or 3 data points in baseline demographic and AEP/SF/CSSS measures. For all participants, AEP decreased between CBD initiation and the 12-week visit (40.8 vs. 33.2; p < 0.0001) with stable AEP scores thereafter (all p ≥ 0.14). Chalfont Seizure Severity Scale scores were 80.7 at baseline, decreasing to 39.2 at 12 weeks (p < 0.0001) and stable CSSS thereafter (all p ≥ 0.19). Bi-weekly SF decreased from a mean of 144.4 at entry to 52.2 at 12 weeks (p = 0.01) and remained stable thereafter (all p ≥ 0.65). Analyses of the pediatric and adult subgroups revealed similar patterns. Most patients were treated with dosages of CBD between 20 and 30 mg/kg/day. For the first time, this prospective, open-label safety study of CBD in TRE provides evidence for significant improvements in AEP, CSSS, and SF at 12 weeks that are sustained over the 48-week duration of treatment.

Long-term safety and treatment effects of cannabidiol in children and adults with treatment-resistant epilepsies: Expanded access program results

Objective

Since 2014, cannabidiol (CBD) has been administered to patients with treatment‐resistant epilepsies (TREs) in an ongoing expanded‐access program (EAP). We report interim results on the safety and efficacy of CBD in EAP patients treated through December 2016.

Methods

Twenty‐five US‐based EAP sites enrolling patients with TRE taking stable doses of antiepileptic drugs (AEDs) at baseline were included. During the 4‐week baseline period, parents/caregivers kept diaries of all countable seizure types. Patients received oral CBD starting at 2‐10 mg/kg/d, titrated to a maximum dose of 25‐50 mg/kg/d. Patient visits were every 2‐4 weeks through 16 weeks and every 2‐12 weeks thereafter. Efficacy endpoints included the percentage change from baseline in median monthly convulsive and total seizure frequency, and percentage of patients with ≥50%, ≥75%, and 100% reductions in seizures vs baseline. Data were analyzed descriptively for the efficacy analysis set and using the last‐observation‐carried‐forward method to account for missing data. Adverse events (AEs) were documented at each visit.

Results

Of 607 patients in the safety dataset, 146 (24%) withdrew; the most common reasons were lack of efficacy (89 [15%]) and AEs (32 [5%]). Mean age was 13 years (range, 0.4‐62). Median number of concomitant AEDs was 3 (range, 0‐10). Median CBD dose was 25 mg/kg/d; median treatment duration was 48 weeks. Add‐on CBD reduced median monthly convulsive seizures by 51% and total seizures by 48% at 12 weeks; reductions were similar through 96 weeks. Proportion of patients with ≥50%, ≥75%, and 100% reductions in convulsive seizures were 52%, 31%, and 11%, respectively, at 12 weeks, with similar rates through 96 weeks. CBD was generally well tolerated; most common AEs were diarrhea (29%) and somnolence (22%).

Significance

Results from this ongoing EAP support previous observational and clinical trial data showing that add‐on CBD may be an efficacious long‐term treatment option for TRE.

Systematic reanalysis of genomic data improves quality of variant interpretation

As genomic sequencing expands, so does our knowledge of the link between genetic variation and disease. Deeper catalogs of variant frequencies improve identification of benign variants, while sequencing affected individuals reveals disease-associated variation. Accumulation of human genetic data thus makes reanalysis a means to maximize the benefits of clinical sequencing. We implemented pipelines to systematically reassess sequencing data from 494 individuals with developmental disability. Reanalysis yielded pathogenic or likely pathogenic (P/LP) variants that were not initially reported in 23 individuals, 6 described here, comprising a 16% increase in P/LP yield. We also downgraded 3 LP and 6 variants of uncertain significance (VUS) due to updated population frequency data. The likelihood of identifying a new P/LP variant increased over time, as ~22% of individuals who did not receive a P/LP variant at their original analysis subsequently did after 3 years. We show here that reanalysis and data sharing increase the diagnostic yield and accuracy of clinical sequencing.

Video-EEG study in an adult and a child with eyelid myoclonia with absences

Two patients with eyelid myoclonia with absences (EMA) are described. Videotape of the eyelid myoclonia in one patient is presented. An interesting feature in one patient was the induction of clinical seizures only with daylight, and in another the presence of rare, focal, epileptiform discharges during drowsiness. Valproic acid only partially controlled eyelid myoclonia in both cases. Lamotrigine, alone or in combination with valproate, can be used as an alternative but was ineffective in our cases. [Published with video sequences].

Pharmacokinetic study of levetiracetam in children

PURPOSE

The pharmacokinetics of the novel antiepileptic drug (AED) levetiracetam and its major metabolite, ucb L057, were studied in children with partial seizures in a multicenter, open-label, single-dose study.

METHODS

Twenty-four children (15 boys, nine girls), 6 to 12 years old, received a single dose of levetiracetam (20 mg/kg) as an adjunct to their stable regimen of a single concomitant AED, followed by a 24-h pharmacokinetic evaluation.

RESULTS

In children, the half-lives of levetiracetam and its metabolite ucb L057 were 6.0 +/- 1.1 and 8.1 +/-2.7 hours, respectively. The Cmax and area under the curve (AUC) of levetiracetam equated for a 1-mg/kg dose were lower in children (Cmax, norm=1.33 plus minus 0.35 microg/ml; AUCnorm=12.4 +/- 3.5 microg/h/ml) than in adults (Cmax, norm=1.38 +/- 0.05 microg/ml; AUCnorm=11.48 +/- 0.63 microg/h/ml), whereas the renal clearance was higher. The apparent body clearance (1.43 +/- 0.36 ml/min/kg) was approximately 30-40% higher in children than in adults. Levetiracetam was generally well tolerated.

CONCLUSIONS

On the basis of these data, a daily maintenance dose equivalent to 130-140% of the usual daily adult maintenance dosage (1,000-3,000 mg/day) in two divided doses, on a weight-normalized level (mg/kg/day) is initially recommended. Clinical efficacy trials in children are ongoing with dosages of 20 to 60 mg/kg/day.

Efficacy of vagal nerve stimulation in children with medically refractory epilepsy

OBJECTIVE

The effects of vagal nerve stimulation (VNS) on seizure frequency and quality of life were analyzed retrospectively in children with medically refractory epilepsy.

METHODS

Thirty-eight children aged 11 months to 16 years underwent implantation of vagal nerve stimulators. Age of seizure onset, duration of epilepsy, and seizure type and frequency were recorded preoperatively. Age at implantation, length of follow-up, seizure type and frequency, and change in quality of life (QOL) were recorded postoperatively. Changes in QOL were assigned a QOL score by the caretakers on a visual analog scale of -1 (much worse) to +1 (much improved).

RESULTS

The median follow-up period was 12 months (range, 10-18 mo). Eleven (29%), 15 (39%), 5 (13%), and 7 (18%) children had greater than 90% reduction, 50 to 90% reduction, less than 50% reduction, and no reduction in seizure frequency, respectively. For all children, seizure reduction by seizure type was as follows: atonic (80%), absence (65%), complex partial (48%), and generalized tonicoclonic (45%). The mean change in QOL score was 0.61. Eighty-six percent of the children had QOL scores of 0.5 (improved) or higher. Follow-up of at least 6 months was associated with greater seizure reduction (P = 0.05) and higher QOL score (P < 0.01). Seizure reduction was greater in children with onset of epilepsy after 1 year of age (P < 0.05). The age of the child and duration of epilepsy were not associated with greater or lesser degrees of seizure reduction.

CONCLUSION

VNS provided improvements in seizure control for the majority of children regardless of age. QOL was improved in the majority of children with VNS. VNS should be considered for children with medically refractory epilepsy who have no surgically resectable focus.

Ketosis and epilepsy: 31P spectroscopic imaging at 4.1 T

PURPOSE

To determine whether changes in the high-energy phosphates occur with use of the ketogenic diet in patients with intractable epilepsy.

METHODS

31P magnetic resonance spectroscopic imaging studies were performed at 4.1 T in seven patients with intractable epilepsy (four Lennox-Gastaut syndrome, one absence, one primary generalized tonic-clonic, and one partial complex) before and after institution of the ketogenic diet. Coronal 1H anatomic imaging also was performed to provide correlation to the 31P data.

RESULTS

Taking the patients as a group, the ratio of phosphocreatine (PC)/gamma-adenosine triphosphate (ATP) measured at baseline (regular diet) compared with that measured after the ketogenic diet showed a small but significant increase from 0.61+/-0.08 to 0.69+/-0.08 (p < 0.05). Comparing the ratio of PCr inorganic phosphorus (Pi) measured at baseline with the postketogenic diet, there was a significant increase from 2.45+/-0.27 to 2.99+/-0.44 (p < 0.05).

CONCLUSIONS

As a group, improvement of energy metabolism occurs with use of the ketogenic diet. This is in agreement with the chronic ketosis studies performed earlier in rodents.

Rasmussen's encephalitis with concomitant cortical dysplasia: the role of GluR3

The role of the glutamate receptor GluR3 in Rasmussen's encephalitis is actively under investigation. Autoimmune processes with this receptor as the target are currently theorized. We provide an additional case of pathologically proved Rasmussen's encephalitis (with concomitant cortical dysplasia) in the presence of antibodies against the GluR3 receptor.

Additional modalities for treating acute seizures in children: overview

The pharmacologic interventions for treatment of acute repetitive seizures and those for treatment of status epilepticus are similar. The choice of treatment should be based on the drug's onset of action, spectrum of anticonvulsant activity, route and ease of administration, elimination half-life, therapeutic margin of safety, and redistribution from the central nervous system. Treatment should be initiated early in patients who are prone to seizure clusters or prolonged partial seizures that may generalize or progress to status epilepticus. Benzodiazepines have become first-line drugs for treatment of acute seizures and status epilepticus, followed by phenytoin/fosphenytoin and phenobarbital. Short-acting benzodiazepines, including diazepam, lorazepam, clonazepam, and midazolam, can decrease the frequency of emergency department visits if given at the appropriate times. The recently approved intravenous formulation of valproate may be of use in children receiving oral valproate who develop breakthrough seizures caused by subtherapeutic plasma levels that are secondary to missed doses or an inability to tolerate oral valproate.

Dystonia with motor delay in compound heterozygotes for GTP-cyclohydrolase I gene mutations

Mutations in the GTP-cyclohydrolase I (GCH) gene have been identified as a cause of two disorders: autosomal dominant hereditary progressive dystonia/dopa-responsive dystonia (HPD/DRD) and autosomal recessive GCH-deficient hyperphenylalaninemia (HPA). Detailed clinical descriptions and genetic analysis of patients with phenotypes intermediate between HPD/DRD (mild) and GCH-deficient HPA (severe) have not been reported. We conducted genomic DNA sequencing of the GCH gene in two patients (Cases 1 and 2) manifesting generalized dystonia responsive to levodopa and severe developmental motor delay. In the pedigree of Patient 1, there were HPD/DRD patients in three generations preceding the index case. Patients 1 and 2 were compound heterozygotes with maternally and paternally transmitted mutations in the coding region of the GCH gene. In both compound heterozygotes, tetrahydrobiopterin (BH4) levels in cerebrospinal fluid were lower than those in HPD/DRD. Administration of BH4, in addition to levodopa, further improved the symptomatology of Patient 1. Our data demonstrate a new phenotype of GCH deficiency associated with compound heterozygosity for GCH gene mutations and suggest the usefulness of combined BH4 and levodopa therapy for this disorder.

Oral phenylalanine loading in dopa-responsive dystonia: a possible diagnostic test

To determine if there is abnormal phenylalanine and biopterin metabolism in patients with dopa-responsive dystonia (DRD), we measured plasma levels of phenylalanine, tyrosine, biopterin, and neopterin at baseline, and 1, 2, 4, and 6 hours after an oral phenylalanine load (100 mg/kg). Seven adults with DRD, two severely affected children with DRD, and nine adult controls were studied. All patients had phenylalanine and tyrosine concentrations within the normal range at baseline. In the adult patients, phenylalanine levels were higher than in controls at 2, 4, and 6 hours post-load (p < 0.0005); tyrosine concentrations were lower than control levels at 1, 2, and 4 hours post-load (p < 0.05). Phenylalanine to tyrosine ratios were elevated in patients at all times post-load (p < 0.0005). Biopterin levels in the patients were decreased at baseline and 1, 2, and 4 hours post-load (p < 0.005). Pretreatment with tetrahydrobiopterin (7.5 mg/kg) normalized phenylalanine and tyrosine profiles in two adult patients. In the children with DRD, phenylalanine to tyrosine ratios were slightly elevated at baseline. Following phenylalanine loading, the phenylalanine profiles were similar to those seen in the adult patients but there was no elevation in plasma tyrosine. Baseline biopterin levels were lower in the children with DRD than in the adult patients or the controls and there was no increase in biopterin post-load. In both the children and adults with DRD, neopterin concentrations did not differ from control values at baseline or after phenylalanine load. The results are consistent with decreased liver phenylalanine hydroxylase activity due to defective synthesis of tetrahydrobiopterin in patients with DRD. The findings show that a phenylalanine load may be useful in the diagnosis of this disorder.

Long-chain 3-hydroxyacyl-coenzyme A dehydrogenase (L-CHAD) deficiency in a patient with the Bannayan-Riley-Ruvalcaba syndrome

Bannayan-Riley-Ruvalcaba syndrome (BRRS) is an autosomal dominant condition of macrocephaly in combination with lipomas/hemangiomas, hypotonia, developmental delay, and a lipid myopathy. The etiology of the lipid storage myopathy has been unclear. We describe a black boy with findings of BRRS who also has a defect in long-chain fatty acid oxidation expressed in cultured skin fibroblasts as a deficiency of long-chain-L-3-hydroxyacyl-CoA dehydrogenase (L-CHAD). He also has an abnormal brain MRI and increased size of both lower limbs. We present this child because of his unusual combination of findings, and postulate that L-CHAD deficiency may be the cause of the lipid myopathy in BRRS.

Surgical treatment for epilepsy in cerebral tuberous sclerosis

Tuberous sclerosis (TS) is an autosomal dominant hamartiosis and hamartomatosis with variable expression that is commonly associated with medically intractable seizures. Patients with TS complex (TSC) frequently have multiple brain lesions that can give rise to seizure activity. We report 9 patients with TSC who underwent epilepsy surgery at the Mayo Clinic between 1986 and 1990. Surgical procedures performed included cortical resection (n = 2) and stereotaxic lesionectomy (n = 7). Neuropathologic diagnoses were cortical tubers (n = 7) and glioneural hamartomas (n = 2). Three of 9 patients had multifocal interictal scalp epileptiform EEG activity; however, ictal recordings identified the focus of seizure activity, which in all cases corresponded to a prominent neuroimaging abnormality. Our patients have been followed for 10-72 months (mean 35 months). Four patients are seizure-free with medication, 2 are seizure-free without medication, 2 had > 80% reduction in seizure frequency, and 1 experienced only an initial temporary reduction in seizure frequency. Postoperative EEG recordings showed absence of epileptiform abnormalities in the 5 patients who are seizure-free; the other 4 patients continue to have multifocal abnormalities. These data suggest that epilepsy surgery may be beneficial in selected patients with TSC despite multifocal EEG and neuroimaging abnormalities.

Bilateral periodic lateralized epileptiform discharges in Mycoplasma encephalitis

Status epilepticus and prolonged coma developed in two patients with respiratory tract infections caused by Mycoplasma pneumoniae. Serial electroencephalography initially revealed bilateral, independent, periodic, lateralized epileptiform discharges. This pattern was replaced several days later by other electroencephalographic abnormalities.

Morphometric studies in dominant olivopontocerebellar atrophy. Comparison of cell losses with amino acid decreases

We present a correlation of the morphometric cell density analysis with previous biochemical findings for the inferior olivary nucleus and Purkinje cell layer of the cerebellum from 10 patients (three kindreds) with dominant olivopontocerebellar atrophy. We have analyzed brain amino compounds of these patients and found a decrease of aspartic acid and glutamic acid in the cerebellar cortex and of aspartic acid in the inferior olives. The cell density analysis revealed decreased cell counts, with a mean of 34% of olivary cells and 42% of Purkinje cells surviving when compared with 10 control brains. The cell counts were then correlated with the amino acid analyses. The correlation coefficient for aspartic acid content and surviving neurons in the inferior olive was .87 and that for aspartic acid content and Purkinje cell density was .86. Comparison of glutamic acid content and Purkinje cell density yielded a correlation coefficient of .75. The correlations appear to indicate a relationship between these particular cells or the area they occupy and the decreased content of the two amino acids.

Prognosis in Sturge-Weber disease: comparison of unihemispheric and bihemispheric involvement

One hundred two patients with Sturge-Weber disease who were seen at the Mayo Clinic between 1942 and 1986 were studied retrospectively to determine the difference in prognosis between unihemispheric (88 patients) and bihemispheric (14 patients) involvement. Seizures occurred in 63 with unihemispheric involvement and 13 with bihemispheric; the mean age at onset of seizures was 24 months in the former and 6 months in the latter. Of the total group, 19% were severely or moderately mentally retarded, 27% were mentally retarded but educable, and 45% had average intelligence. In the bihemispheric involvement group, 46% were severely or moderately mentally retarded, 38% were retarded but educable, and only 8% had average intelligence. Bilateral involvement of the brain by Sturge-Weber disease is associated with earlier onset of seizures and worse prognosis for mental development compared with unilateral involvement.