Unverricht-Lundborg progressive myoclonus epilepsy in Oman

Autistic features in Unverricht-Lundborg disease

We studied three patients with Unverricht-Lundborg disease for autistic features along with other clinical features associated with progressive myoclonus epilepsy. We diagnosed this disease based on noise and touch sensitive myoclonus, ataxia, cognitive decline, typical EEG features, normal MRI of the brain and applied Children's Global Assessment Scale and Childhood Autism Spectrum Test to these children. The CGAS score was 35 in two and 50 in one of them. CAST scores were above 15 in all of three of them. Autistic features may be an important clinical feature of this disease. History and physical examination for myoclonus should probably be taken in autistic children.

Unverricht-Lundborg disease: Clinical course and seizure management based on the experience of polish centers

The purpose of this paper was to present our experience following the longterm treatment of 11 patients with Unverricht-Lundborg disease (ULD) confirmed by molecular testing.

METHODS

We analyzed the clinical course, cognitive state, neuroimaging and neurophysiology results.

RESULTS

The data were collected from 9 unrelated families (F/M: 4/7) aged 25-49. The most frequent early manifestations of ULD include generalized tonic-clonic seizures (GTCS) accompanied by myoclonus 2 years later. Myoclonus was observed in all of the patients; its severity made it impossible for 91% to move independently. In two patients- mild atrophy of brain were observed in the MRI. More than half of the patients who underwent evoked potential presented no abnormalities. The dominant EEG-change was slow background activity in all of the patients. Seven patients had generalized seizure activity. The patients received antiepileptic therapy modifications depending on the severity of symptoms and stage of the disease. Five patients received N-acetyl-cysteine.

CONCLUSIONS

ULD patients require anti-epileptic polytherapy, mostly benefitting from managing GTCS and myoclonus with valproic acid and clonazepam treatment. Patients may benefit from add-on therapy with levetiracetam or topiramate. An increase in myoclonus, resulting from the progressive nature of the disease leads to significant disability in the majority of patients.

Different patterns of movement-related cortical oscillations in patients with myoclonus and in patients with spinocerebellar ataxia

OBJECTIVE

To assess whether different patterns of EEG rhythms during a Go/No-go motor task characterize patients with cortical myoclonus (EPM1) or with spinocerebellar ataxia (SCA).

METHODS

We analyzed event-related desynchronization (ERD) and synchronization (ERS) in the alpha and beta-bands during visually cued Go/No-go task in 22 patients (11 with EPM1, 11 with SCA) and 11 controls.

RESULTS

In the Go condition, the only significant difference was a reduced contralateral beta-ERS in the EPM1 patients compared with controls; in the No-go condition, the EPM1 patients showed prolonged alpha-ERD in comparison with both controls and SCA patients, and reduced or delayed alpha- and beta-ERS in comparison with controls. In both conditions, the SCA patients, unlike EPM1 patients and controls, showed minimal or absent lateralization of alpha- and beta-ERD.

CONCLUSIONS

EPM1 patients showed abnormal ERD/ERS dynamics, whereas SCA patients mainly showed defective ERD lateralization.

SIGNIFICANCE

A different behavior of ERS/ERD distinguished the two patient groups: the pattern observed in EPM1 suggests a prominent defect of inhibition occurring in motor cortex contralateral to activated segment, whereas the pattern observed in SCA suggested a defective lateralization attributable to the damage of cerebello-cortical network, which is instead marginal in patients with cortical myoclonus.

Cerebellar Involvement in Patients with Mild to Moderate Myoclonus Due to EPM1: Structural and Functional MRI Findings in Comparison with Healthy Controls and Ataxic Patients

EPM1 (epilepsy, progressive myoclonic 1; Unverricht-Lundborg disease, OMIM #254800) is the most frequent form of progressive myoclonus epilepsy. Previous findings have suggested that its pathophysiology mainly involves the cerebellum, but the evaluation of cerebellar dysfunction is still unsatisfactory. The aim of this study was to assess the structural and functional involvement of the cerebellum in EPM1. We used voxel-based morphometry and spatially unbiased infra-tentorial template analyses of structural magnetic resonance imaging (MRI) scans, and functional MRI (fMRI) scans during block and event-related go/no-go motor tasks to study 13 EPM1 patients with mild to moderate myoclonus. We compared the results with those obtained in 12 age-matched healthy controls (HCs) and in 12 patients with hereditary spinocerebellar ataxia (SCA). Structural analyses revealed different patterns of atrophic changes in the EPM1 and SCA patients: in the former, they involved both cerebrum and cerebellum but, in the latter, only the cerebellum. During fMRI, block and event-related go/no-go tasks similarly activated the cerebellum and cerebrum in the EPM1 patients and HCs, whereas both tasks revealed much less cerebellar activation in the SCA patients than in the other two groups. Volumetric evaluation of the EPM1 patients showed that the cerebellum seemed to be marginally involved in a widespread atrophic process, and fMRI showed that it was not functionally impaired during motor tasks.

Progressive volume loss and white matter degeneration in cstb-deficient mice: a diffusion tensor and longitudinal volumetry MRI study

Unverricht-Lundborg type progressive myoclonus epilepsy (EPM1, OMIM 254800) is an autosomal recessive disorder characterized by onset at the age of 6 to 16 years, incapacitating stimulus-sensitive myoclonus and tonic-clonic epileptic seizures. It is caused by mutations in the gene encoding cystatin B. Previously, widespread white matter changes and atrophy has been detected both in adult EPM1 patients and in 6-month-old cystatin B-deficient mice, a mouse model for the EPM1 disease. In order to elucidate the spatiotemporal dynamics of the brain atrophy and white matter changes in EPM1, we conducted longitudinal in vivo magnetic resonance imaging and ex vivo diffusion tensor imaging accompanied with tract-based spatial statistics analysis to compare volumetric changes and fractional anisotropy in the brains of 1 to 6 months of age cystatin B-deficient and control mice. The results reveal progressive but non-uniform volume loss of the cystatin B-deficient mouse brains, indicating that different neuronal populations possess distinct sensitivity to the damage caused by cystatin B deficiency. The diffusion tensor imaging data reveal early and progressive white matter alterations in cystatin B-deficient mice affecting all major tracts. The results also indicate that the white matter damage in the cystatin B-deficient brain is most likely secondary to glial activation and neurodegenerative events rather than a primary result of CSTB deficiency. The data also show that diffusion tensor imaging combined with TBSS analysis provides a feasible approach not only to follow white matter damage in neurodegenerative mouse models but also to detect fractional anisotropy changes related to normal white matter maturation and reorganisation.

3D texture analysis reveals imperceptible MRI textural alterations in the thalamus and putamen in progressive myoclonic epilepsy type 1, EPM1

Progressive myoclonic epilepsy type 1 (EPM1) is an autosomal recessively inherited neurodegenerative disorder characterized by young onset age, myoclonus and tonic-clonic epileptic seizures. At the time of diagnosis, the visual assessment of the brain MRI is usually normal, with no major changes found later. Therefore, we utilized texture analysis (TA) to characterize and classify the underlying properties of the affected brain tissue by means of 3D texture features. Sixteen genetically verified patients with EPM1 and 16 healthy controls were included in the study. TA was performed upon 3D volumes of interest that were placed bilaterally in the thalamus, amygdala, hippocampus, caudate nucleus and putamen. Compared to the healthy controls, EPM1 patients had significant textural differences especially in the thalamus and right putamen. The most significantly differing texture features included parameters that measure the complexity and heterogeneity of the tissue, such as the co-occurrence matrix-based entropy and angular second moment, and also the run-length matrix-based parameters of gray-level non-uniformity, short run emphasis and long run emphasis. This study demonstrates the usability of 3D TA for extracting additional information from MR images. Textural alterations which suggest complex, coarse and heterogeneous appearance were found bilaterally in the thalamus, supporting the previous literature on thalamic pathology in EPM1. The observed putamenal involvement is a novel finding. Our results encourage further studies on the clinical applications, feasibility, reproducibility and reliability of 3D TA.

Progressive myoclonus epilepsy

The progressive myoclonus epilepsies (PMEs) consist of a group of diseases with myoclonic seizures and progressive neurodegeneration, with onset in childhood and/or adolescence. Lafora disease is a neuronal glycogenosis in which normal glycogen is transformed into starch-like polyglucosans that accumulate in the neuronal somatodendritic compartment. It is caused by defects of two genes of yet unknown function, one encoding a glycogen phosphatase (laforin) and the other an ubiquitin E3 ligase (malin). Early cognitive deterioration, visual seizures affecting over half, and slowing down of EEG basic activity are three major diagnostic clues. Unverricht-Lundborg disease is presently thought to be due to damage to neurons by lysosomal cathepsins and reactive oxygen species due to absence of cystatin B, a small protein that inactivates cathepsins and, by ways yet unknown, quenches damaging redox compounds. Preserved cognition and background EEG activity, action myoclonus early morning and vertex spikes in REM sleep are the diagnostic clues. Sialidosis, with cherry-red spot, neuronopathic Gaucher disease, with paralysis of verticality, and ataxia-PME, with ataxia at onset in the middle of the first decade, are also lysosomal diseases. How the lysosomal defect culminates in myoclonus and epilepsy in these conditions remains unknown.

Thickened skull, scoliosis and other skeletal findings in Unverricht-Lundborg disease link cystatin B function to bone metabolism

PURPOSE

Unverricht-Lundborg disease (EPM1) is a rare type of inherited progressive myoclonic epilepsy resulting from mutations in the cystatin B gene, CSTB, which encodes a cysteine cathepsin inhibitor. Cystatin B, cathepsin K, and altered osteoclast bone resorption activity are interconnected in vitro. This study evaluated the skeletal characteristics of patients with EPM1.

METHODS

Sixty-six genetically verified EPM1 patients and 50 healthy controls underwent head MRI. Skull dimensions and regional calvarial thickness was measured perpendicular to each calvarial bone from T1-weighted 3-dimensional images using multiple planar reconstruction tools. All clinical X-ray files of EPM1 patients were collected and reviewed by an experienced radiologist. A total of 337 X-ray studies were analyzed, and non-traumatic structural anomalies, dysplasias and deformities were registered.

RESULTS

EPM1 patients exhibited significant thickening in all measured cranial bones compared to healthy controls. The mean skull thickness was 10.0±2.0mm in EPM1 patients and 7.6±1.2mm in healthy controls (p<0.001). The difference was evident in all age groups and was not explained by former phenytoin use. Observed abnormalities in other skeletal structures in EPM1 patients included thoracic scoliosis (35% of EPM1 patients) and lumbar spine scoliosis (35%), large paranasal sinuses (27%), accessory ossicles of the foot, and arachnodactyly (18%).

CONCLUSIONS

Skull thickening and an increased prevalence of abnormal findings in skeletal radiographs of patients with EPM1 suggest that this condition is connected to defective cystatin B function. These findings further emphasize the role of cystatin B in bone metabolism in humans.

Sensorimotor, visual, and auditory cortical atrophy in Unverricht-Lundborg disease mapped with cortical thickness analysis

BACKGROUND AND PURPOSE

EPM1, caused by mutations in the CSTB gene, is the most common form of PME. The most incapacitating symptom of EPM1 is action-activated and stimulus-sensitive myoclonus. The clinical severity of the disease varies considerably among patients, but so far, no correlations have been observed between quantitative structural changes in the brain and clinical parameters such as duration of the disease, age at onset, or myoclonus severity. The aim of this study was to evaluate possible changes in CTH of patients with EPM1 compared with healthy controls and to correlate those changes with clinical parameters.

MATERIALS AND METHODS

Fifty-three genetically verified patients with EPM1 and 70 healthy volunteers matched for age and sex underwent 1.5T MR imaging. T1-weighted 3D images were analyzed with CTH analysis to detect alterations. The patients were clinically evaluated for myoclonus severity by using the UMRS. Higher UMRS scores indicate more severe myoclonus.

RESULTS

CTH analysis revealed significant thinning of the sensorimotor and visual and auditory cortices of patients with EPM1 compared with healthy controls. CTH was reduced with increasing age in both groups, but in patients, the changes were confined specifically to the aforementioned areas, while in controls, the changes were more diffuse. Duration of the disease and the severity of myoclonus correlated negatively with CTH.

CONCLUSIONS

Cortical thinning in the sensorimotor areas in EPM1 correlated significantly with the degree of the severity of the myoclonus and is most likely related to the widespread stimulus sensitivity in EPM1.