Natural clusters of tuberous sclerosis complex (TSC)-associated neuropsychiatric disorders (TAND): new findings from the TOSCA TAND research project.

BACKGROUND: Tuberous sclerosis complex (TSC)-associated neuropsychiatric disorders (TAND) have unique, individual patterns that pose significant challenges for diagnosis, psycho-education, and intervention planning. A recent study suggested that it may be feasible to use TAND Checklist data and data-driven methods to generate natural TAND clusters. However, the study had a small sample size and data from only two countries. Here, we investigated the replicability of identifying natural TAND clusters from a larger and more diverse sample from the TOSCA study. METHODS: As part of the TOSCA international TSC registry study, this embedded research project collected TAND Checklist data from individuals with TSC. Correlation coefficients were calculated for TAND variables to generate a correlation matrix. Hierarchical cluster and factor analysis methods were used for data reduction and identification of natural TAND clusters. RESULTS: A total of 85 individuals with TSC (female:male, 40:45) from 7 countries were enrolled. Cluster analysis grouped the TAND variables into 6 clusters: a scholastic cluster (reading, writing, spelling, mathematics, visuo-spatial difficulties, disorientation), a hyperactive/impulsive cluster (hyperactivity, impulsivity, self-injurious behavior), a mood/anxiety cluster (anxiety, depressed mood, sleep difficulties, shyness), a neuropsychological cluster (attention/concentration difficulties, memory, attention, dual/multi-tasking, executive skills deficits), a dysregulated behavior cluster (mood swings, aggressive outbursts, temper tantrums), and an autism spectrum disorder (ASD)-like cluster (delayed language, poor eye contact, repetitive behaviors, unusual use of language, inflexibility, difficulties associated with eating). The natural clusters mapped reasonably well onto the six-factor solution generated. Comparison between cluster and factor solutions from this study and the earlier feasibility study showed significant similarity, particularly in cluster solutions. CONCLUSIONS: Results from this TOSCA research project in an independent international data set showed that the combination of cluster analysis and factor analysis may be able to identify clinically meaningful natural TAND clusters. Findings were remarkably similar to those identified in the earlier feasibility study, supporting the potential robustness of these natural TAND clusters. Further steps should include examination of larger samples, investigation of internal consistency, and evaluation of the robustness of the proposed natural clusters

The visual system in eyelid myoclonia with absences

Objective: To investigate the functional and structural brain correlates of eyelid myoclonus and absence seizures triggered by eye closure (eye closure sensitivity [ECS]). Methods: Fifteen patients with eyelid myoclonus with absences (EMA, Jeavons syndrome), 14 patients with idiopathic generalized epilepsies (IGE) without ECS, and 16 healthy controls (HC) underwent an electroencephalography (EEG)-correlated functional magnetic resonance imaging (fMRI) and voxel brain morphometry (VBM) protocol. The functional study consisted of 30-second epochs of eyes-open and eyes-closed conditions. The following EEG events were marked and the relative fMRI maps obtained: (1) eye closure times, (2) spontaneous blinking, and (3) spontaneous and eye closure-triggered spike and wave discharges (SWD; for EMA and IGE). Within-group and betweengroups comparisons were performed for fMRI and VBM data as appropriate. Results: In EMA compared to HC and IGE we found: (1) higher blood oxygenation level-dependent (BOLD) signal related to the eye closure over the visual cortex, the posterior thalamus, and the network implicated in the motor control of eye closure, saccades, and eye pursuit movements; and (2) increments in the gray matter concentration at the visual cortex and thalamic pulvinar, whereas decrements were observed at the bilateral frontal eye field area. No BOLD differences were detected when comparing SWD in EMA and IGE. Interpretation: Results demonstrated altered anatomo-functional properties of the visual system in EMA. These abnormalities involve a circuit encompassing the occipital cortex and the cortical/subcortical systems physiologically involved in the motor control of eye closure and eye movements. Our work supports EMA as an epileptic condition with distinctive features and provides a contribution to its classification among epileptic syndromes

Early-onset seizure variant of Rett syndrome: Definition of the clinical diagnostic criteria.

BACKGROUND: Rett syndrome is a severe neurodevelopmental disorder affecting almost exclusively females. Among Rett clinical variants, the early-onset seizure variant describes girls with early onset epilepsy and it is caused by mutations in CDKL5. METHODS: Four previously reported girls and five new cases with CDKL5 mutation, ranging from 14 months to 13 years, were evaluated by two clinical geneticists, classified using a severity score system based on the evaluation of 22 different clinical signs and compared with 128 classic Rett and 25 Zappella variant MECP2-mutated patients, evaluated by the same clinical geneticists. Clinical features were compared with previously described CDKL5 mutated patients. Both the statistical and the descriptive approach have been used to delineate clinical diagnostic criteria. RESULTS: All girls present epilepsy with onset varying from 10 days to 3 months. Patients may present different type of seizures both at onset and during the whole course of the disease; multiple seizure types may also occur in the same individual. After treatment with antiepileptic drugs patients may experience a short seizure-free period but epilepsy progressively relapses. Typical stereotypic hand movements severely affecting the ability to grasp are present. Psychomotor development is severely impaired. In the majority of cases head circumference is within the normal range both at birth and at the time of clinical examination. CONCLUSION: For the practical clinical approach we propose to use six necessary and eight supportive diagnostic criteria. Epilepsy with onset between the first week and 5 months of life, hand stereotypies, as well as severe hypotonia, are included among the necessary criteria