Acute effect of transcranial direct current stimulation on photoparoxysmal response.

INTRODUCTION: Transcranial direct current stimulation (tDCS) is a non-invasive technique, used to modify the excitability of the central nervous system. The main mechanism of tDCS is to change the excitability by subthreshold modulation by affecting neuronal membrane potentials in the direction of depolarization or repolarization. tDCS was previously investigated as an alternative adjunctive therapy in patients with epilepsy. We aimed here to investigate the acute effect of tDCS on the photoparoxysmal response (PPR) in EEG. METHODS: We enrolled 11 consecutive patients diagnosed with idiopathic generalized epilepsy who had PPR on at least 2 EEGs. Three different procedures, including sham, anodal, and cathodal tDCS were applied to the patients at intervals of one week by placing the active electrode over Oz, for 2 mA, 20 minutes. Spike-wave indices (SWI) were counted by two researchers independently and were compared during intermittent photic stimulation (IPS) on EEGs both before and after the application. RESULTS: After cathodal tDCS, SWI increased compared to baseline EEG and sham EEG in 3 patients, and after anodal tDCS, SWI increased in 2 patients. Although the SWI values did not change significantly, 8 patients reported subjectively that the applications were beneficial for them and that they experienced less discomfort during photic stimulation after the sessions. There were no side effects except transient skin rash in one patient, only. CONCLUSIONS: In our sham controlled tDCS study with both cathodal and anodal stimulation, our data showed that there was no significant change in SWI during IPS, despite subjective well-being. tDCS' modulatory effect does not seem to act in the acute phase on EEG parameters after photic stimulation.

Let there be light: Inhibitory effect of photic stimulation on spike frequency in patients with mesial temporal lobe epilepsy with hippocampal sclerosis.

Inhibition of epileptic discharges and seizures by sensory stimuli is an interesting phenomenon, but highly understudied. Here, we aimed to investigate the modulation of epileptiform discharges in patients with mesial temporal lobe epilepsy associated with hippocampal sclerosis (MTLE-HS) via photic stimulation (PS), based on a hypothesis that light stimulation may activate thalamocortical networks limiting the propagation of interictal epileptiform discharges. In order to do so, all EEGs performed in patients diagnosed with MTLE-HS were reviewed to include available recordings with definite epileptiform abnormalities. These were reevaluated by two clinical neurophysiologists independently, and spikes were counted in a blinded manner to calculate spike index (SI) (spikes per minute-pm) for baseline EEG, hyperventilation (HV), and PS periods. Our final study group consisted of 30 MTLE-HS patients with a mean age of 34.5 (±12.5) years. Mean seizure frequency was 38.1 per year (±46.6), and the mean disease duration was 16.2 years (±12.1). Mean SI during baseline was calculated as 1.17 pm (±1.4), during HV 2.1 pm (±2.8) and during PS 0.8 pm (±2.5). As a result, SI was significantly lower during PS compared to baseline (p = 0.001). Our findings suggest that PS has a remarkable inhibitory effect on epileptiform discharges in MTLE-HS patients, indicating the need for further prospective investigations for clinical translation.

Perceptions of Modulatory Factors in Migraine and Epilepsy: A Multicenter Study.

Background: Migraine and epilepsy are both common episodic disorders, typically precipitated or inhibited by some modulatory factors (MFs). Objective: To assess the self-perception of MFs in patients with migraine (PWM) compared to patients with epilepsy (PWE) with a standardized protocol in different countries. Methods: Transcultural multicenter comparative cross-sectional study. All consecutive patients who fulfilled the ICHD-3 criteria for migraine and ILAE's criteria for epilepsy, with at least 1 year of follow-up were interviewed with a semi-structured questionnaire on clinical and epidemiological data and were asked to identify all experienced MFs from a provided list. Results: A total of 608 individuals were surveyed at five university referral centers in Brazil, Guatemala, Lithuania and Turkey. Two hundred and nineteen (91.6%) PWM and 305 (82.7%) PWE identified attack precipitating factors (PFs; p < 0.001). The most frequent three PFs reported by epilepsy patients were: "lack of sleep" (56.6%), "emotional stress" (55.3%), "negative feelings" (53.9%), while among migraine patients "emotional stress" (81.6%), "lack of sleep" (77.8%), "negative feelings" (75.7%) were cited. Inhibitory factors (IFs) for the episodes were reported by 68 (28.5%) PWM and 116 (31.4%) PWE. "Darkness" was the most common one, described by 35.6% of PWM whereas "positive feelings" reported by 10.6% of PWE. Most MFs are concordant across the countries but some transcultural differences were noted. Conclusion: The MFs of migraine and epilepsy attacks and their varying frequencies according to different countries were investigated with the same standardized questionnaire, for the first time. MFs were recognized very often in both migraine and epilepsy cohorts, but in distinct disease-specific prevalence, being more frequent in migraine. Recognition of self-perceived MFs may be helpful for the management of both illnesses.

Functional connectivity disturbances of ascending reticular activating system and posterior thalamus in juvenile myoclonic epilepsy in relation with photosensitivity: A resting-state fMRI study.

OBJECTIVE: Juvenile myoclonic epilepsy (JME) is typified by the occurrence of myoclonic seizures after awakening, though another common trait is myoclonic seizures triggered by photic stimulation. We aimed to investigate the functional connectivity (FC) of nuclei in the ascending reticular activating system (ARAS), thalamus and visual cortex in JME with and without photosensitivity. METHODS: We examined 29 patients with JME (16 photosensitive (PS), 13 non- photosensitive-(NPS)) and 28 healthy controls (HCs) using resting-state functional magnetic resonance imaging (rs-fMRI). Seed-to-voxel FC analyses were performed using 25 seeds, including the thalamus, visual cortex, and ARAS nuclei. RESULTS: Mesencephalic reticular formation seed revealed significant hyperconnectivity between the bilateral paracingulate gyrus and anterior cingulate cortex in JME group, and in both JME-PS and JME-NPS subgroups compared to HCs (pFWE-corr < 0.001; pFWE-corr < 0.001; pFWE-corr = 0.002, respectively). Locus coeruleus seed displayed significant hyperconnectivity with the bilateral lingual gyri, intracalcarine cortices, occipital poles and left occipital fusiform gyrus in JME-PS group compared to HCs (pFWE-corr <0.001). Additionally, locus coeruleus seed showed significant hyperconnectivity in JME-PS group compared to JME-NPS group with a cluster corresponding to the bilateral lingual gyri and right intracalcarine cortex (pFWE-corr < 0.001). Lastly, the right posterior nuclei of thalamus revealed significant hyperconnectivity with the right superior lateral occipital cortex in JME-PS group compared to HCs (pFWE-corr < 0.002). CONCLUSIONS: In JME, altered functional connectivity of the arousal networks might contribute to the understanding of myoclonia after awakening, whereas increased connectivity of posterior thalamus might explain photosensitivity.

[Validity and Reliability Studies of Modified Mini Mental State Examination (MMSE-E) For Turkish Illiterate Patients With Diagnosis of Alzheimer Disease]. / Egitimsizler Için Modifiye Edilen Mini Mental Testin (MMSE-E) Türk Toplumunda Alzheimer Hastaligi Tanisinda Geçerlik ve Güvenilirlik Çalismasi.

OBJECTIVE: To investigate the validity and reliability of modified Mini Mental State Examination (MMSE-E) for illiterate patients in a Turkish population with Alzheimer's disease (AD). METHOD: A total of 107 illiterate patients with Alzheimer's Disease (women: 65, men: 42) and 68 illiterate healthy volunteer subjects (women: 36, men: 32) were included in the study. MMSE-I and Geriatrics Depression Scale were performed on all subjects, Alzheimer patients were also administered Basic Activities of Daily Living (B- ADL). Clinical Dementia Rating (CDR) was used to determine the severity of disease, while a receiver operating characteristic (ROC) analysis was performed to analyze the cut-off scores of MMSE-I, and the positive/negative predictive values that were calculated for the optimal cut-off scores. Internal consistency was measured using Cronbach's coefficient . Additionally, correlations between total MMSE-I score and the CDR, B-ADL, and GDS scores were examined. RESULTS: The MMSE-I scores significantly and inversely correlated with CDR (-0.82, p=0.000) and B-ADL scores (-0.051, p=0.000). The optimal cut-off points of MMSE-I were 23/24, which yielded a sensitivity of 99.0% - %100.0, a specificity of 98.5% - 97.0%, and an AUC of 1.0/1.0, respectively. Reliability of the MMSE-I was high α = 0.70). CONCLUSION: The total MMSE-I score was able to differentiate the AD group from the control group.