Deep brain stimulation in a patient with progressive myoclonic epilepsy and ataxia due to potassium channel mutation (MEAK). A case report and review of the literature.

Progressive myoclonic epilepsy (PME) is characterized by prominent myoclonus, generalized tonic-clonic seizures, and less often focal, tonic, or absence seizures. The KCNC1 mutation is responsible for specific clinical phenotype of PME which has been defined as myoclonic epilepsy and ataxia due to potassium channel mutation (MEAK). We present a case of a 44 years-old male patient with genetically proven MEAK who underwent subthalamic nucleus/substantia nigra (STN/SNr) deep brain stimulation (DBS) for his pharmacological-refractory myoclonus and drug-resistant epilepsy (DRE). Since the age of 4-5 years, the patient had been suffering from intention tremor, and later the myoclonic jerks, ataxia involving the upper limbs and walking difficulties worsened. The first bilateral tonic-clonic seizure (BTCS) occurred at the age of 22. The patient agreed to staged bilateral implantation of DBS electrodes placed in the STN/SNr region. The follow-up lasts more than 24 months. The myoclonic jerks assessed by Unified Myoclonus Rating Scale (UMRS) were reduced by nearly 70 % and BTCS was completely abolished. The patient's ataxia and dysarthria did not improve. Early diagnosis with genetic testing may significantly help in counseling patients with PME and enables to undertake the surgical approach targeting the STN/SNr.

Correlations between cerebellar and brain volumes, cognitive impairments, ApoE levels, and APOE genotypes in patients with AD and MCI.

Due to the increasing incidence of Alzheimer's disease (AD), many studies have aimed to improve its diagnosis. Particular attention has been focused on measuring volumes of brain structures. Only few studies have investigated whether the cerebellar volume changes with the stage of dementia. It is controversial whether the serum apolipoprotein E (ApoE) level is an appropriate AD marker. This study was designed to clarify the significance of both cerebellar volume measurements and ApoE level measurements as markers of neurodegenerative changes. This study included 55 subjects with AD, 30 subjects with mild cognitive impairments (MCI), and a control group with 30 subjects. We measured the brain, cerebellum, and brain stem volumes with magnetic resonance imaging (MRI). We determined serum ApoE levels, APOE genotypes, and neuropsychological test scores. In the control group, we found that ApoE levels were significantly higher for subjects with the APOE 2/3 genotype than those with the 4/4 genotype. This finding may indicate that ApoE plays a protective role against AD development in subjects with the APOE 2/3 genotype. ApoE levels were not significantly different in patients with AD and MCI. No correlations were found between serum ApoE levels and Mini-Mental State Examination (MMSE) scores or the volumes of brain structures. This study could not confirm the appropriateness of the cerebellum volume as an early AD marker. Correlations were found between cerebellar volume, brain volume, and the MMSE scores.