Ayla Humphrey

Characterization of Autism in Young Children With Tuberous Sclerosis Complex

Both cognitive impairment and autism are common in the tuberous sclerosis complex, but the relationship between the 2 diagnoses has not been formally explored. The authors evaluated 20 clinic-referred children with tuberous sclerosis complex at ages 18, 24, 36, and 60 months and classified them as autism, autism spectrum disorder, or normal on the basis of the Autism Diagnostic Observation Schedule. Using the Mullen Scale of Early Learning, cognitive function in each subgroup was assessed. The authors then analyzed the subscores of the Autism Diagnostic Observation Schedule in children with autism. Children with autism showed significantly more global cognitive impairment than those without autism. In addition, all children had some baseline cognitive impairment and the majority had deficits in play scores. The authors conclude that clinic-referred children with tuberous sclerosis complex and autism are at considerable risk for cognitive impairment. These characteristics may help to guide more tailored services for these high-risk children.

LEGO ® Therapy and the Social Use of Language Programme: An Evaluation of Two Social Skills Interventions for Children with High Functioning Autism and Asperger Syndrome

LEGO® therapy and the Social Use of Language Programme (SULP) were evaluated as social skills interventions for 6–11 year olds with high functioning autism and Asperger Syndrome. Children were matched on CA, IQ, and autistic symptoms before being randomly assigned to LEGO or SULP. Therapy occurred for 1 h/week over 18 weeks. A no-intervention control group was also assessed. Results showed that the LEGO therapy group improved more than the other groups on autism-specific social interaction scores (Gilliam Autism Rating Scale). Maladaptive behaviour decreased significantly more in the LEGO and SULP groups compared to the control group. There was a non-significant trend for SULP and LEGO groups to improve more than the no-intervention group in communication and socialisation skills.

The Tuberous Sclerosis 2000 Study: presentation, initial assessments and implications for diagnosis and management

Aims The Tuberous Sclerosis 2000 Study is the first comprehensive longitudinal study of tuberous sclerosis (TS) and aims to identify factors that determine prognosis. Mode of presentation and findings at initial assessments are reported here. Methods Children aged 0–16 years newly diagnosed with TS in the UK were evaluated. Results 125 children with TS were studied. 114 (91%) met clinical criteria for a definite diagnosis and the remaining 11 (9%) had pathogenic TSC1 or TSC2 mutations. In families with a definite clinical diagnosis, the detection rate for pathogenic mutations was 89%. 21 cases (17%) were identified prenatally, usually with abnormalities found at routine antenatal ultrasound examination. 30 cases (24%) presented before developing seizures and in 10 of these without a definite diagnosis at onset of seizures, genetic testing could have confirmed TS. 77 cases (62%) presented with seizures. Median age at recruitment assessment was 2.7 years (range: 4 weeks–18 years). Dermatological features of TS were present in 81%. The detection rate of TS abnormalities was 20/107 (19%) for renal ultrasound including three cases with polycystic kidney disease, 51/88 (58%) for echocardiography, 29/35 (83%) for cranial CT and 95/104 (91%) for cranial MRI. 91% of cases had epilepsy and 65% had intellectual disability (IQ<70). Conclusions Genetic testing can be valuable in confirming the diagnosis. Increasing numbers of cases present prenatally or in early infancy, before onset of seizures, raising important questions about whether these children should have EEG monitoring and concerning the criteria for starting anticonvulsant therapy.

Monozygotic twins with tuberous sclerosis discordant for the severity of developmental deficits

A pair of monozygotic male twins with tuberous sclerosis (TS) were followed between 18 months and 3 years of age. Twin A with 25 large cortical tubers and hence extensive brain involvement was moderately mentally retarded and met criteria for autism. The other twin had more (n = 31) but smaller tubers. He was not mentally retarded and did not meet criteria for autism. This study provides evidence that nongenetic factors such as extent of brain abnormality and not just number of cortical tubers are important in determining phenotypic variability in TS. The findings also raise questions about the mechanisms giving rise to autism in TS.

Autistic regression associated with seizure onset in an infant with tuberous sclerosis.

We report here on a male diagnosed with tuberous sclerosis at 6 months of age. The child was treated with vigabatrin at age 6 months after an abnormal electroencephalogram but before onset of seizures. Vigabatrin was discontinued at age 13 months to avoid possible visual field defects. At 21 months, the child developed partial seizures with secondary generalization and infantile spasms. Standardized developmental assessments were performed at 12, 18, 24, 30, and 36 months of age. Cognitive and social development were normal until age 21 months and the onset of seizures. When assessed at 24 months, the child met criteria for autism and learning disability. This case indicates that the onset of epilepsy during an early stage in brain development can be associated with autistic regression and persistent developmental disorder. The case suggests the need to consider if possible visual field defects with vigabatrin outweigh the potentially deleterious effects of uncontrolled seizures.

Biological markers of intellectual disability in tuberous sclerosis

BACKGROUND Intellectual disability (ID) is highly prevalent in tuberous sclerosis (TS). Putative neurobiological risk factors include indices of cortical tuber (CT) load and epilepsy. We have used univariate and multivariate analyses, including both CT and epilepsy measures as predictors, in an attempt to clarify the pattern of cross-sectional associations between these variables and ID in TS. METHOD Forty-eight children, adolescents and young adults with TS were identified through regional specialist clinics. All subjects underwent thorough history taking and examination, and had brain magnetic resonance imaging (MRI) scans. The number and regional distribution of CTs was recorded. Subjects were assigned to one of nine ordered intellectual quotient (IQ) categories (range 130) using age-appropriate tests of intelligence. RESULTS On univariate analyses, ID was significantly associated with both a history of infantile spasm (IS) (Z=-2.49, p=0.01) and total CT count (Spearmans rho=-0.30, p=0.04). When controlling for total CT count, the presence of CTs in frontal (regression coefficient=-2.43, p=0.02) and temporal (regression coefficient=-1.60, p=0.02) lobes was significantly associated with ID. In multivariate analyses the association between IS and ID was rendered insignificant by the inclusion of the presence of CTs in temporal and frontal lobes, both of which remained associated (p=0.05 and p=0.06 respectively) with ID. CONCLUSIONS The presence of CTs in specific brain regions as opposed to a history of IS was associated with ID in TS. The significance of these findings is discussed in relation to previous work in TS, and the neural basis of intelligence.

A prospective longitudinal study of early cognitive development in tuberous sclerosis - a clinic based study.

We report a prospective longitudinal study of cognitive development in a series of 20 clinic-referred infants with Tuberous Sclerosis. The infants were seen between the ages of 11 and 37 months and were assessed regularly at 6-month periods using a within-subjects repeated measures design. Assessment using the Mullen Scales of Early Learning, a measure of cognitive and motor showed that with the exception of one child, all children had composite developmental quotients that fell into the mentally retarded range of intellectual functioning. In general, the infants’ developmental quotients changed little between 12 and 36 months of age. Developmental progress was evident; however, with small incremental changes in raw scores for subjects over the course of the study. In three children, the developmental quotient changed by more than 20 points during the course of the study. The findings are considered in relation to the neurobiological risk factors for cognitive development in Tuberous Sclerosis.

Intellectual abilities in tuberous sclerosis complex: risk factors and correlates from the Tuberous Sclerosis 2000 Study.

BACKGROUND Tuberous sclerosis complex (TSC) is associated with intellectual disability, but the risk pathways are poorly understood. METHOD The Tuberous Sclerosis 2000 Study is a prospective longitudinal study of the natural history of TSC. One hundred and twenty-five UK children age 0-16 years with TSC and born between January 2001 and December 2006 were studied. Intelligence was assessed using standardized measures at ≥2 years of age. The age of onset of epilepsy, the type of seizure disorder, the frequency and duration of seizures, as well as the response to treatment was assessed at interview and by review of medical records. The severity of epilepsy in the early years was estimated using the E-Chess score. Genetic studies identified the mutations and the number of cortical tubers was determined from brain scans. RESULTS TSC2 mutations were associated with significantly higher cortical tuber count than TSC1 mutations. The extent of brain involvement, as indexed by cortical tuber count, was associated with an earlier age of onset and severity of epilepsy. In turn, the severity of epilepsy was strongly associated with the degree of intellectual impairment. Structural equation modelling supported a causal pathway from genetic abnormality to cortical tuber count to epilepsy severity to intellectual outcome. Infantile spasms and status epilepticus were important contributors to seizure severity. CONCLUSIONS The findings support the proposition that severe, early onset epilepsy may impair intellectual development in TSC and highlight the potential importance of early, prompt and effective treatment or prevention of epilepsy in tuberous sclerosis.

Intellectual development before and after the onset of infantile spasms: A controlled prospective longitudinal study in tuberous sclerosis

Infantile spasms (IS) have long been suspected to be a risk factor for impairment in intellectual development, but there are no controlled, prospective longitudinal data in well‐characterized conditions to confirm this suspicion. We tested the hypothesis in a longitudinal study of children with tuberous sclerosis (TS), who have a high risk of developing IS.

The Early Childhood Epilepsy Severity Scale (E-Chess).

PURPOSE We have developed the Early Childhood Epilepsy Severity Scale (E-Chess) to quantify the severity of epilepsy in infants and young children with tuberous sclerosis as an aid to the evaluation of treatment efficacy and the investigation of the influence of epilepsy severity on development. METHODS Twenty infants aged 11-36 months with a diagnosis of tuberous sclerosis participated in the study. From the literature, six potential measures of epilepsy severity were identified: time period over which seizures occurred; seizure frequency; number of seizure types; occurrence and duration of status epilepticus; number of anticonvulsant medications used; response to treatment. The variables were given a score, usually from 0 to 3, a higher score indicating greater severity. For each child, these variables were scored over consecutive 1 year time periods by three independent raters. We employed restricted and nonrestricted factor analytic models to identify the latent structure of the six items. RESULTS The six severity items had a unidimensional structure. All severity indicators loaded highly on the latent epilepsy severity factor (>0.77), with the exception of the status indicator which had a poor loading (<0.40) and was excluded from further analyses. Goodness of fit indices were all well within the acceptable criteria for model fit. The E-Chess score at 12 months was significantly predictive of scores at 24 and 36 months. CONCLUSIONS A single continuous latent variable accounts for the variation in five of the six epilepsy severity indicators under study. These form the Early Childhood Epilepsy Severity Scale. The predictive validity of the E-Chess was satisfactory. The E-Chess provides an epilepsy severity score that can be easily used to assess epilepsy severity in tuberous sclerosis and would merit evaluation in other early onset childhood epilepsies.