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Your search keyword '"Esa Mervaala"' showing total 3 results
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3 results on '"Esa Mervaala"'

1. Progressive myoclonic epilepsy type 1 (EPM1) patients present with abnormal 1H MRS brain metabolic profiles associated with cognitive function

Author

Jelena Hyppönen, Vili Paanila, Marja Äikiä, Päivi Koskenkorva, Mervi Könönen, Ritva Vanninen, Esa Mervaala, Reetta Kälviäinen, and Juhana Hakumäki

Subjects
EPM1, MRS, Spectroscopy, Brain, Neuropsychology, Cognition, Computer applications to medicine. Medical informatics, R858-859.7, Neurology. Diseases of the nervous system, RC346-429
Abstract

Purpose: Progressive myoclonic epilepsy, type 1A (EPM1, Unverricht-Lundborg disease), is a rare neurodegenerative autosomal recessive disorder characterized by stimulus-sensitive and action myoclonus and tonic-clonic epileptic seizures. Patients develop neurological symptoms, including ataxia, intention tremor, and dysarthria, over time, with relatively limited and nonspecific MRI atrophy findings. The effects of the disease on brain metabolism are largely unknown. Method: Eighteen EPM1 patients (9 M, 9F) underwent clinical evaluation and neuropsychological testing, which included the assessment of intellectual ability, verbal memory, and psychomotor and executive functions. Magnetic resonance spectroscopy (MRS) and imaging (MRI) were performed on a 1.5 T MRI system. 2D MRS chemical shift imaging (CSI) maps (TE = 270) were obtained from the following regions of the brain: basal ganglia, thalamus, insula, splenium, and occipital white and gray matter, and N-acetyl-aspartate (NAA)-, choline (Cho)-, and lactate (Lac)-to-creatine (Cr) ratios were analyzed. Ten healthy age-and sex-matched subjects (5M, 5F) were used as controls for MRS. Results: We found significant brain metabolic changes involving lactate, NAA, and choline, which are widespread in the basal ganglia, thalamic nuclei, insula, and occipital areas of EPM1 patients. Changes, especially in the right insula, basal ganglia, and thalamus, were associated with intellectual abilities and impairment of the psychomotor and executive functions of EPM1 patients. Conclusion: Multiple brain metabolic alterations suggest the presence of neurodegeneration associated with EPM1 progression. The changes in metabolite ratios are associated with the neurocognitive dysfunction caused by the disease. However, the role of MRS findings in understanding pathophysiology of EPM1 warrants further studies.

Published
2023
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2. Short- and long-interval intracortical inhibition in EPM1 is related to genotype

Author

Katri Silvennoinen, Laura Säisänen, Jelena Hyppönen, Saara M. Rissanen, Pasi A. Karjalainen, Sasha D'Ambrosio, Diego Jimenez‐Jimenez, Sara Zagaglia, John C. Rothwell, Simona Balestrini, Sanjay M. Sisodiya, Petro Julkunen, Esa Mervaala, and Reetta Kälviäinen

Subjects
Neurology, Neurology (clinical)
Abstract

Progressive myoclonic epilepsy type 1 (EPM1) is caused by biallelic alterations in the CSTB gene, most commonly dodecamer repeat expansions. Although transcranial magnetic stimulation (TMS)-induced long-interval intracortical inhibition (LICI) was previously reported to be normal in EPM1, short-interval intracortical inhibition (SICI) was reduced. We explored the association between these measures and the clinical and genetic features in a separate group of patients with EPM1.TMS combined with electromyography was performed under neuronavigation. LICI was induced with an inter-stimulus interval (ISI) of 100 ms, and SICI with ISIs of 2 and 3 ms, and their means (mSICIs) were expressed as the ratio of conditioned to unconditioned stimuli. LICI and mSICI were compared between patients and controls. Nonparametric correlation was used to study the association between inhibition and parameters of clinical severity, including the Unified Myoclonus Rating Scale (UMRS); among patients with EPM1 due to biallelic expansion repeats, also the association with the number of repeats was assessed.The study protocol was completed in 19 patients (15 with biallelic expansion repeats and 4 compound heterozygotes), and 7 healthy, age- and sex-matched control participants. Compared to controls, patients demonstrated significantly less SICI (median mSICI ratio 1.18 vs 0.38; p .001). Neither LICI nor SICI was associated with parameters of clinical severity. In participants with biallelic repeat expansions, the number of repeats in the more affected allele (greater repeat number [GRN]) correlated with LICI (rho = 0.872; p .001) and SICI (rho = 0.689; p = .006).Our results strengthen the finding of deranged γ-aminobutyric acid (GABA)ergic inhibition in EPM1. LICI and SICI may have use as markers of GABAergic impairment in future trials of disease-modifying treatment in this condition. Whether a higher number of expansion repeats leads to greater GABAergic impairment warrants further study.

Published
2022

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