Narcolepsy is one among the disorders of central hypersomnolence characterized by excessive daytime sleepiness not related to disturbances in nocturnal sleep or misalignment in circadian rhythms. The cardinal symptom of this group of disorders is disabling daytime sleepiness, characterized by the repeated episodes of irresistible daytime sleepiness or lapses into sleep in monotonous situations, but also under unusual conditions such as eating. Narcolepsy is defined as type 1 and type 2 on the basis of the presence of cataplexy. The most pathognomonic feature of narcolepsy type 1 is cataplexy, which is characterized by sudden episodes of brief loss of muscle tone-sparing consciousness, usually triggered by strong emotions. Other nonspecific symptoms associated with rapid eye movement sleep dissociation include fragmentation of nocturnal sleep, hypnagogic or hypnopompic hallucinations, and sleep paralysis. The pathophysiology of narcolepsy type 1 is well established as the deficiency of hypocretin (orexin) signaling in the lateral hypothalamus. In narcolepsy type 2, on the other hand, hypocretin levels are not decreased, and it has been suggested that there is probably a partial deficiency in hypocretin signaling system to cause excessive daytime sleepiness but not severe enough to cause cataplexy. Instead of types 1 and 2, primary (idiopathic) narcolepsy, familial narcolepsy, secondary (symptomatic) narcolepsy, and narcolepsy plus (hereditary forms with additional neurological symptoms) forms were suggested to better classify the clinical entities. In this paper, the diagnosis of symptomatic or secondary narcolepsy is reviewed and classified based on the underlying pathophysiologic mechanisms.

Background: This study aims to determine which factors increase the risk of intracerebral hemorrhage after tissue plasminogen activator (tPA) treatment in patients with acute ischemic stroke and to investigate whether there is a relationship between the need for antihypertensive therapy during and after tPA infusion and the risk of intracerebral hemorrhage. Materials and Methods: Consecutive patients who applied to our stroke center with acute ischemic stroke and received IV tPA treatment in the first 4.5 h between 2012 and 2020 were included in the study. The demographic data of patients, stroke risk factors, drugs used before the stroke, neurological examinations, cranial computed tomographys (CTs) before and after tPA, antihypertensive usage during IV tPA and in the 24-h period after treatment, hospital mortality rates, and modified Rankin Scale scores in the 3^rd month were evaluated retrospectively. Patients with intracerebral bleeding were divided into groups according to bleeding subtypes and whether they were symptomatic. Results: Intracranial bleeding was detected in 48 of 214 patients included in this study. Nineteen of these (8.8%) were classified as symptomatic intracerebral hemorrhage according to the National Institute of Neurological Disorders and Stroke and 14 (6.5%) according to the definition of the European Cooperative Acute Stroke Study. In the multiple logistic regression analysis, intracranial bleeding was significantly associated with 24^th h systolic blood pressure and the need for antihypertensive usage. Conclusions: Blood pressure regulation should be done carefully during tPA infusion and in the first 24 h. In addition, cranial CT scanning in patients who need antihypertensive usage may enable earlier detection of intracranial bleeding.

Background and Aim: To evaluate the association between psychoacoustical characteristics of tinnitus and audiogram configurations and reveal which theoretical mechanism dominates tinnitus. Materials and Methods: The medical charts of 110 adult participants' 164 ears with tinnitus were retrospectively reviewed. Audiological results, edge frequency, and psychoacoustical characteristics of tinnitus were assessed. Participants were divided into two groups as follows: normal hearing (NH) and sensorineural hearing loss (SNHL). Results: No significant relationship was observed between age, gender, tinnitus pitch, and loudness between the two groups. In the SNHL group, there was a weak positive correlation between tinnitus pitch and frequency of maximum hearing loss (FMHL), and a strong positive correlation between the mean tinnitus loudness at the tinnitus pitch and FMHL. Besides, the edge frequency was positively and weakly correlated with the tinnitus pitch and FMHL. No statistically significant difference was observed between the groups regarding the tinnitus pitch. However, tinnitus loudness was statistically higher in the NH group. No relationship was observed between the audiogram shapes and tinnitus timbre, pitch, and FMHL. In addition, the most likened tinnitus timbre was found to be tonal/whistle in both groups. A moderate positive correlation was observed between the tinnitus pitch and edge frequency in the gradual slope audiograms. Conclusions: The findings obtained in this study supported homeostatic plasticity theories for the SNHL group, and hidden hearing loss for the NH group.

Objective: Tattooing has become more popular, especially in Western culture. We aimed to analyze the impacts of the presence of tattoos in the operative field for posterior thoracolumbar surgery. Methodology: This study was performed using data extracted from the medical files of 15 patients who underwent posterior thoracolumbar surgery between April 2013 and May 2020 in the neurosurgery department of our tertiary care center. Therapeutic, clinical, and cosmetic outcomes after surgery necessitating incision on the tattoo are presented together with a brief discussion of the current literature. Results: Our series consisted of nine women and six men with an average age of 31.03 (range, 17–45) years. The duration of follow-up was 52 (range, 6–90) months. Ten patients underwent posterior spinal stabilization, and a simple discectomy was performed on five patients. The therapeutic outcomes and clinical improvement were satisfactory in all patients. No complications attributed to the presence of tattoos were detected in any patients. Conclusion: Posterior thoracolumbar surgery usually necessitates a midline incision that may unavoidably result in the deformation of a tattoo. Our results yielded that therapeutic and cosmetic results in patients with tattoos in the operative field were acceptable in the vast majority of cases after posterior thoracolumbar surgery.

Introduction: The aim of this study was to compare routine awake electroencephalography (r-EEG), melatonin-induced sleep EEG (m-EEG) and EEG (d-EEG) after sleep deprivation studies in terms of epileptiform anomalies (EA), and to compare d-EEG and m-EEG studies in terms of sleep induction in patients requiring differential diagnosis of epileptic seizure/nonepileptic seizure. Methods: The study included 45 patients aged 18–45 years who had at least one seizure suspected to be epileptic but could not be diagnosed with epilepsy with clinical and laboratory findings. Each patient underwent r-EEG on the 1^st day, d-EEG on the 2^nd day after 24 h of sleeplessness, and m-EEG on the 3^rd day after the administration of 6 mg melatonin following 7 h night sleep. Three separate EEG tracings of the patients were compared for EA. The d-EEG and m-EEG methods were examined for their ability to achieve sleep, total sleep time (ST), and sleep latency (SL). Results: When the detection rate of EA in d-EEG and m-EEG was compared with that of r-EEG, it was found to be significantly higher (P < 0.001) (73.3% with d-EEG, 75.6% with m-EEG, and 35.6% with r-EEG). Sleep was achieved at a rate of 100% after receiving melatonin and at a rate of 97.8% with sleep deprivation. There was no significant difference between d-EEG and m-EEG in terms of mean ST and SL (ST = 58.6 ± 12.6 min and 59.7 ± 8.3 min, respectively; SL = 287.6 ± 484.3 s and 152.2 ± 178.7 s after the start of the EEG, respectively). Conclusions: Sleep EEG is superior to awake EEG in terms of detecting EA. In an EEG study, where melatonin was used to induce sleep, the sleep rate and SL were similar to those of d-EEG, and melatonin did not have an EA increasing or suppressing effect on EEG. Given the ease of application and low side effect profile, it is thought that m-EEG may be an applicable method in the diagnosis of epilepsy.

Objective: Freezing of gait (FOG) is an important concern for both patients with Parkinson's disease (pwPD) and physicians. In this study, we aimed to introduce a study protocol and our initial data. The data were subsequently used in machine learning models to detect FOG episodes using brain activity signals and motion data in the laboratory setting using complex FOG-evoking activities in a sample of pwPD with and without FOG compared with age-matched healthy controls. Subjects and Methods: An experimental task to evoke a FOG episode was designed. This experimental task was tested on two pwPD with FOG in “on” and “off” periods and one healthy control. Brain activity signals and motion data were collected simultaneously using electroencephalography (EEG) and inertial measurement units (IMUs). Results: The whole procedure took about 2 h, during which around 30 min were spent on walking tasks, involving 35 complete tours in the designed 8-m hallway by pwPD. Both EEG and IMUs sensor data could be collected, accompanied by FOG episode data marked by the neurologist. The video recordings of the patient's walking tasks were checked and reanalyzed by the neurologist sometime after the data experiment for marking the beginnings and ends of the observed FOG episodes more precisely. In the end, 24 stops were marked as FOG, which corresponded to 11% of the sensor data collected during the walking tasks. Conclusion: The designed FOG-evoking task protocol could be performed without any adverse effects, and it created enough FOG episodes for analysis. EEG and motion sensor data could be successfully collected without any significant artifacts.

Objective: The objective of this study was to investigate neural responses during subliminal oddball tasks concerning reward-directed motivation to distinguish the P3a and P3b components of evoked P300 potentials. Methods: The subliminal oddball task included congruent/incongruent stimuli and masked prime subliminal stimuli. The task was to push the button when an incongruent stimulus appeared. Participants underwent two pre- and post-break electroencephalogram (EEG) recordings. During the break, the thirst scores of the participants were evaluated. Then, participants consumed three different salty foods in the same amount and completed the remaining two post-break EEG recordings, followed by the second thirst scores evaluation. Finally, participants physically selected lettered cards (A, B, C, and D) to receive a reward and quench their thirst. Results: Thirty participants were enrolled, 28 of whom were included for data analysis. Ten participants selected lettered cards as the given subliminal stimulus (sub⁽⁺⁾ group), and 18 participants selected different lettered cards from the given subliminal stimulus (sub^(–) group). We found a significant increase in post-P3a and post-P3b amplitudes in the sub⁽⁺⁾ group at the Pz/Oz electrodes. Changes in P3b amplitude were significantly higher in the sub⁽⁺⁾ group (2.83 ± 1.14 μV) than in the sub^(–) group (0.62 ± 2.29 μV) at the Pz/Oz electrodes. Correlation analysis revealed that higher thirst scores resulted in higher P3b amplitudes in the sub⁽⁺⁾ group. Conclusion: These findings suggest that reward-directed motivation increases parietal-posterior P3b amplitudes, signifying the involvement of cognitive processes to achieve a reward.