Diffuse cerebral language representation in tuberous sclerosis complex

Abstract

Introduction Tuberous sclerosis complex (TSC) is a multisystem genetic disorder affecting multiple organs, including the brain, and very often associated with epileptic activity. Language acquisition and development seems to be altered in a significant proportion of patients with TSC. In the present study, we used magnetoencephalography (MEG) to investigate spatiotemporal cerebral language processing in subjects with TSC and epilepsy during a reading semantic decision task, compared to healthy control participants. Methods Fifteen patients with TSC and 31 healthy subjects performed a lexico-semantic decision task during MEG recording. Minimum-norm estimates (MNE) were computed allowing identification of cerebral generators of language evoked fields (EF) in each subject. Results Source analysis of the language EF demonstrated early bilateral medial occipital activation (125ms) followed by a fusiform gyrus activation around 135ms. At 270ms post stimuli presentation, a strong cerebral activation was recorded in the left basal temporal language area. Finally, cerebral activations were measured in Wernicke’s area followed by Broca’s area. The healthy control group showed larger and earlier language activations in Broca and Wernicke’s areas compared to TSC patients. Moreover, cerebral activation from Broca’s area was greater than activation from Wernicke’s area in both groups, but this difference between anterior and posterior regions was smaller in the TSC group. Finally, the activation latency difference between Broca and Wernicke’s areas was greater in healthy controls than in TSC patients, which shows that activations in these areas are more serial in control subjects compared to TSC patients in whom activations occur more simultaneously. Conclusions This is the first study to investigate cerebral language pattern in patients with TSC. Compared to healthy controls, atypical neuromagnetic language responses may reflect cerebral reorganization in these patients in response to early epileptogenic activity or presence at birth of multiple brain lesions.

Resting‐State fMRI Networks in Children with Tuberous Sclerosis Complex

“…PLS auditory comprehension score reflects more than a pure auditory measure; it includes predictors of language development, which has been shown to be abnormal in majority of individuals with TSC . Abnormalities in white matter microstructure related to language network have been shown in children with TSC and ASD, and in functional processing of language in adults with TSC …”

Topographical Distribution of Epileptogenic Tubers in Patients With Tuberous Sclerosis Complex

“…21 Within the left hemisphere, these areas of the brain are often considered part of the posterior language area. Interestingly, a series of studies by Gallagher et al 34,35 have shown diffuse changes in language representation and changes in language laterality in patients with tuberous sclerosis complex that appears to be dependent on the history of epilepsy and the presence of tubers in language areas. In particular, these investigators demonstrated that patients with tuberous sclerosis complex having a history of epilepsy or presence of tubers within language areas showed bilateral language patterns.…”

Resective Surgery for Double Epileptic Foci Overlapping Anterior and Posterior Language Areas: A Case of Epilepsy With Tuberous Sclerosis Complex

“…In the patients with lesions involving the left inferior or middle frontal gyri, atypical language areas are noted ( 12 ). In TSC patients, cortical tubers and epileptic activities in language related cortices also alter the distributions of usual language areas to bilateral hemispheres ( 13 ). Although these previous studies indicated the possibility of bilateral language areas, the Wada test and extraoperative mapping revealed motor and language areas approximate to the usual distributions observed in our patient.…”