Time-Dependent Decline in Multifocal Electroretinogram Requires Faster Recording Procedures in Anesthetized Pigs

PURPOSE: The time-dependent effect of anesthetics on the retinal function is debated. We hypothesize that in anesthetized animals there is a time-dependent decline that requires optimized multifocal electroretinogram (mfERG) recording procedures. METHODS: Conventional and four-frame global-flash mfERG recordings were obtained approximately 15, 60, and 150 minutes after the induction of propofol anesthesia (20 pigs) and isoflurane anesthesia (nine pigs). In six of the propofol-anesthetized pigs, the mfERG recordings were split in 3-minute segments. Two to 4 weeks after initial recordings, an intraocular injection of tetrodotoxin (TTX) was given and the mfERG was rerecorded as described above. Data were analyzed using mixed models in SAS statistical software. RESULTS: Propofol significantly decreases the conventional and global-flash amplitudes over time. The only significant effect of isoflurane is a decrease in the global-flash amplitudes. At 15 minutes after TTX injection several of the mfERG amplitudes are significantly decreased. There is a linear correlation between the conventional P1 and the global-flash DR mfERG-amplitude (R(2) = 0.82, slope = 0.72, P < 0.0001). There is no significant difference between the 3-minute and the prolonged mfERG recordings for conventional amplitudes and the global-flash direct response. The global flash–induced component significantly decreases with prolonged mfERG recordings. CONCLUSIONS: A 3-minute mfERG recording and a single stimulation protocol is sufficient in anesthetized pigs. Recordings should be obtained immediately after the induction of anesthesia. The effect of TTX is significant 15 minutes after injection, but is contaminated by the effect of anesthesia 90 minutes after injection. Therefore, the quality of mfERG recordings can be further improved by determining the necessary time-of-delay from intraocular injection of a drug to full effect. TRANSLATIONAL RELEVANCE: General anesthesia is a possible source of error in mfERG recordings. Therefore, it is important to investigate the translational relevance of the results to mfERG recordings in children in general anesthesia

Study on the effect of 40 Hz non-invasive light therapy system. A protocol for a randomized, double-blinded, placebo-controlled clinical trial

IntroductionWith no cure or effective treatment, the prevalence of patients with Alzheimer’s disease (AD) is expected to intensify, thereby increasing the social and financial burden on society. Light-based 40 Hz brain stimulation is considered a novel treatment strategy for patients with AD that may alleviate some of this burden. The clinical trial ALZLIGHT will utilize a novel Light Therapy System (LTS). The LTS uses Invisible Spectral Flicker for non-invasive induction of 40 Hz neural activity. This protocol describes a trial evaluating the efficacy and safety of a light-based 40 Hz brain stimulation in patients with mild-to-moderate AD.Methods62 patients with mild-to-moderate AD will participate in a randomized, double-blinded, placebo-controlled, parallel-group, and single-center trial. The participants will partake in an enrollment period of 1 month, an intervention period of 6 months, and a 1.5-month post-interventional follow-up period. Prior to the baseline measurement (week 0), the patients will be randomized to either active or placebo intervention from baseline (week 0) to post-intervention follow-up (week 26).DiscussionThis protocol describes a randomized, double-blinded, placebo-controlled clinical trial that may increase the understanding of the effect of gamma oscillations in the human brain and how it could be utilized as a novel and important tool for the treatment of AD. The effect is measured through a large, multidisciplinary assessment battery.Clinical trial registration:www.ClinicalTrials.gov, (NCT05260177). Registered on March 2, 2022

Electroconvulsive Therapy in Super Refractory Status Epilepticus: Case Series with a Defined Protocol

Super-refractory status epilepticus (SRSE) represents a neurological emergency that is characterized by a lack of response to the third line of antiepileptic treatment, including intravenous general anesthetics. It is a medical challenge with high morbidity and mortality. Electroconvulsive therapy (ECT) has been recommended as a nonpharmacologic option of treatment after other alternatives are unsuccessful. Its effect on the cessation of SRSE has been minimally investigated. The objective of this article is to analyze the effect of ECT on SRSE. For this purpose, a multidisciplinary team created a protocol based on clinical guidelines similar to those described previously by Ray et al. (2017). ECT was applied to six patients with SRSE after the failure of antiepileptic treatment and pharmacologic coma.The objective of each ECT session was to elicit a motor seizure for at least 20 s. SRSE was resolved in all patients after several days of treatment, including ECT as a therapy, without relevant adverse effects. Thus, ECT is an effective and feasible option in the treatment of SRSE, and its place in the algorithm in treatment should be studied due to the uncommon adverse effects and the noninvasive character of the therapy