Automatic Wake and Deep-Sleep Stage Classification Based on Wigner-Ville Distribution Using a Single Electroencephalogram Signal.

This research paper outlines a method for automatically classifying wakefulness and deep sleep stage (N3) based on the American Academy of Sleep Medicine (AASM) standards. The study employed a single-channel EEG signal, leveraging the Wigner-Ville Distribution (WVD) for time-frequency analysis to determine EEG energy per second in specific frequency bands (δ, θ, α, and entire band). Particle Swarm Optimization (PSO) was used to optimize thresholds for distinguishing between wakefulness and stage N3. This process aims to mimic a sleep technician's visual scoring but in an automated fashion, with features and thresholds extracted to classify epochs into correct sleep stages. The study's methodology was validated using overnight PSG recordings from 20 subjects, which were evaluated by a technician. The PSG setup followed the 10-20 standard system with varying sampling rates from different hospitals. Two baselines, T1 for the wake stage and T2 for the N3 stage, were calculated using PSO to ascertain the best thresholds, which were then used to classify EEG epochs. The results showed high sensitivity, accuracy, and kappa coefficient, indicating the effectiveness of the classification algorithm. They suggest that the proposed method can reliably determine sleep stages, being aligned closely with the AASM standards and offering an intuitive approach. The paper highlights the strengths of the proposed method over traditional classifiers and expresses the intentions to extend the algorithm to classify all sleep stages in the future.

The Relationship of Depression Level and Physical Activity with Postural Control in Geriatric Individuals.

Introduction: The aim of this study was to investigate the relationships between functional performance, physical activity level, and depression level with postural control in older adults. Methods: Data were collected from 48 community-dwelling subjects aged ≥65 years. As measurement parameters, Sway mobile balance application for postural control, Sit - Stand Test for lower extremity muscle strength, SenseWear armband for physical activity level, Mini-Mental Test for mental status and Beck Depression Inventory (BDI) for depression level were used. Results: Sway score was positively correlated with total energy expenditure (TEE) (r=0.28, p=0.04) and number of steps (r=0.30, p=0.03) and negatively correlated with BDI (r=-0.33, p=0.03). The BDI score was negatively correlated with all physical activity parameters. While lower extremity strength, which indicates functional performance, showed moderate-good correlation with physical activity parameters, it showed moderate negative correlation with BDI (r=-0.63, p<0.001). Body mass index value positively correlated with TEE (r=0.34, p=0.01). Conclusions: The results of this study showed a significant correlation between postural control, physical activity, and depression level. A sufficient level of physical activity is important for the maintenance and improvement of depression level and postural control system. The relationship between physical activity, depression level and postural control should not be ignored in healthy aging.

Primed Tactile Stimulus Processing during Sleep.

The aim was to investigate how the primed and unprimed non-painful tactile stimuli during sleep would be processed. A total of 22 healthy subjects (19.55 ± 1.10 years) were randomly divided into two groups. The same stimuli were applied to both groups, but the study group (SG) received them twice (daytime and sleep), whereas the control group (CG) received them only during sleep. A 40-channel PSG and a pneumatic tactile stimulator unit were used. Evoked potential components of the CZ electrode were examined in four sleep stages (N1, N2, N3, and REM). The Mann-Whitney U test was used for group comparison, and the Wilcoxon test was used for in-group evaluations. The P50 and N300 response components were observed in all sleep stages in both groups. P50 decreased as sleep deepened in the SG. The N300 increased as sleep deepened and started to decrease again in the REM stage. Moreover, in N1, the amplitudes of P200-N300 and N300-P450 in the SG were significantly greater than those in the CG. The fact that P50 was observed even in N3 indicates that bottom-up sensory processing continues during sleep. Moreover, the central processing of primed and unprimed stimuli exhibited dynamic differences. Furthermore, an increase in N300 amplitude suggests suppressive processes to facilitate and maintain sleep.

The Influence of Medicine Approaches on Patient Trust, Satisfaction, and Loyalty.

The increase in traditional and complementary medicine (TCM) methods has revealed the necessity of determining relevant behavioral tendencies among healthcare users. In our study, the evaluation of TCM approaches of healthcare users living in North Cyprus in terms of treatment effectiveness, patient trust and patient satisfaction, and the effects of these variables on patient loyalty, were investigated. Data were collected utilizing the scale approach as well as the survey technique in order to measure the variables in the study. A total of 452 participants completed the survey. TCM has a positive effect on treatment effectiveness, patient trust and patient satisfaction. Patient trust and patient satisfaction have a positive effect on patient loyalty, whereas treatment effectiveness did not have a significant effect on patient loyalty. There is a significant and positive mediating effect of patient trust and patient satisfaction between TCM and patient loyalty. However, the mediating effect of treatment effectiveness is not significant between TCM and patient loyalty. This study will help researchers and practitioners understand the importance of attitude, trust, effectiveness, satisfaction and loyalty in relation to TCM. It is suggested that studies that measure the behaviors of patients should increase in order to obtain better health outcomes.

Effects of the Mediterranean diet on the components of metabolic syndrome.

Metabolic syndrome, also as known as Syndrome X or Insulin Resistance Syndrome, is a complex health problem featuring visceral obesity (the main diagnostic criterion), insulin resistance, dyslipidemia and high blood pressure. Currently, this health condition has gained a momentum globally while raising concerns among health-related communities. The World Health Organization, American Heart Association and International Diabetes Federation have formulated diagnostic criteria for metabolic syndrome. Diet and nutrition can influence this syndrome: for example, the Western diet is associated with increased risk of metabolic syndrome, whereas the Nordic and Mediterranean diets and the Dietary Approach to Stop Hypertension are potentially beneficial. The Mediterranean diet can affect the components of metabolic syndrome due to its high dietary fiber, omega 3 and 9 fatty acids, complex carbohydrates, antioxidants, minerals, vitamins and bioactive substances, such as polyphenols. These nutrients and bioactive substances can combat obesity, dyslipidemia, hypertension and diabetes mellitus. The mechanisms by which they do so are generally related to oxidative stress, inflammation (the most common risk factors for metabolic syndrome) and gastrointestinal function. The literature also shows examples of positive effects of the Mediterranean diet on the metabolic syndrome. In this review of the literature, we shed light on the effects, mechanisms and dynamic relationship between the Mediterranean diet and metabolic syndrome.

Modification of Mediterranean Diet Pyramid from an Island's perspective / Alteração da Pirâmide Alimentar Mediterrânea na perspectiva de uma Ilha

ABSTRACT Objective The present study aimed to determine traditional and local food consumption and adherence to the Mediterranean diet in Cyprus. And also, aimed to improve their adherence to the Mediterranean diet and traditional and local food consumption. From this point, this current study aimed to revise the Cyprus Mediterranean Diet Pyramid, based on the Current Mediterranean Diet Pyramid. Methods The sample size was calculated as a minimum of 386 according to a 95.0% confidence interval, and a 5.0% error. This study was conducted online between November 2020-April 2021 in Cyprus. All volunteers were invited to this study on the national public internet platforms. Participant´s adherence to the Mediterranean diet was determined by the Mediterranean Diet Adherence Screener. Traditional and local food consumption frequencies were determined by a Food Frequency Questionnaire. A novel Cyprus Mediterranean Diet Pyramid was developed with traditional and local food items for Cyprus. The modification was also aimed to safeguard planet health, to increase traditional food consumption and adherence to the Mediterranean diet. Results 1,007 adults (78.0% native islanders/Cypriots) participated voluntarily in the current study. The mean Mediterranean Diet Adherence Screener score was 7.55±2.30 points and only 34.4% had high adherence to the Mediterranean diet. According to their responses, there was a need to increase use of olive oil, vegetables, fruits, fish, and red wine consumption and to decrease red meat and dessert consumption. According to responses to the Mediterranean Diet Adherence Screener and their traditional/local food consumption frequencies an up-to-date Cyprus Mediterranean Diet Pyramid was done hence a national food pyramid for Cyprus. Commonly consumed traditional and local foods were added to the pyramid to facilitate increased adaptation of the Mediterranean diet in the general population. Adequately consumed foods were added to make it more region-specific and rarely consumed foods were added to help to increase consumption. Conclusion This modification is believed to be instrumental to increase Mediterranean diet adaptation, traditional/local food consumption and decrease the impact of nutrition on the planet´s health. And also, this modification can shed light on the development of the other traditional food pyramids.

RESUMO Objetivo Este estudo teve como objetivo determinar o consumo alimentar tradicional e local, bem como a adesão à dieta mediterrânea no Chipre. Também teve como objetivo melhorar a adesão à dieta mediterrânea e ao consumo de alimentos tradicionais e locais. A partir desse ponto, este trabalho atual teve como objetivo revisar a Pirâmide da Dieta Mediterrânea do Chipre, que é baseada na Pirâmide da Dieta Mediterrânea Atual. Métodos O tamanho da amostra foi calculado com um mínimo de 386 de acordo com intervalo de confiança de 95,0% e erro de 5,0%. Este estudo foi realizado online entre novembro de 2020 e abril de 2021 em Chipre. Todos os voluntários foram convidados para esta análise nas plataformas públicas nacionais de internet. A adesão dos participantes à dieta mediterrânea foi avaliada pelo Medidor de Adesão à Dieta Mediterrânea. As frequências de consumo alimentar tradicional e local foram determinadas pelo Questionário de Frequência Alimentar. Foi desenvolvida uma nova Pirâmide da Dieta Mediterrânica de e para o Chipre, com alimentos tradicionais e locais. A modificação teve também como objetivo salvaguardar a saúde do planeta, aumentar o consumo de alimentos tradicionais e a adesão à dieta mediterrânea. Resultados No total de 1.007 adultos (78,0% naturais da ilha/cipriotas) participaram voluntariamente no estudo. A pontuação média obtida no Medidor de Adesão à Dieta Mediterrânea foi de 7,55±2,30 pontos, com apenas 34,4% aderindo fortemente à dieta mediterrânea. De acordo com as suas respostas, houve necessidade de aumentar a utilização de azeite, vegetais, frutas, peixe e vinho tinto, bem como de diminuir o consumo de carnes vermelhas e sobremesas. Com base nas suas respostas ao Medidor de Adesão à Dieta Mediterrânea e as suas frequências de consumo alimentar tradicional/local, foi feita uma pirâmide da Dieta Mediterrânea do Chipre atualizada, ou seja, uma pirâmide alimentar nacional para o Chipre. Alimentos locais e regionais comumente consumidos foram adicionados à pirâmide para aumentar a adesão à dieta mediterrânea. Alimentos consumidos de acordo com as recomendações foram adicionados para torná-los específico da região, e alimentos pouco consumidos foram adicionados para ajudar a aumentar o consumo. Conclusão Acredita-se que esta modificação seja determinante para aumentar a adaptação da dieta mediterrânea e o consumo de alimentos tradicionais e locais, além de diminuir o impacto da nutrição na saúde do planeta. Ainda, essa modificação pode lançar luz sobre o desenvolvimento das outras pirâmides alimentares tradicionais.

Investigation of the perceptual and cognitive asymmetry in the auditory system in patients with adolescent idiopathic scoliosis.

BACKGROUND: Studies have shown that perceptual and cognitive asymmetries are present in the auditory system in patients with adolescent idiopathic scoliosis (AIS). The Dichotic Listening (DL) paradigm was formerly performed in non-forced (NF) conditions only, and no study has examined the conditions of attention to one ear. OBJECTIVE: To investigate the perceptual and cognitive asymmetry in the auditory system in patients with AIS as well as the asymmetry changes according to the curvature characteristics of patients with AIS. METHOD: The DL paradigm was performed on 38 patients with AIS and 10 healthy individuals in all conditions (NF, Forced Right [FR], Forced Left [FL]). RESULTS: In the NF and FL conditions, the mean number of correct responses for the left ear was significantly lower in patients with AIS than in healthy individuals (p < 0.05). The correct responses for the right ear in the NF condition, right and left ear in the FR condition, and right ear in the FL condition did not show a significant difference between the groups (p > 0.05). Also, there was no difference between patients with AIS with both functional 3-curve and 4-curve (p > 0.05). CONCLUSION: Our study indicates perceptual and cognitive asymmetry or lateralisation in the auditory system in patients with AIS. The asymmetry might be caused by the inability to direct their attention to the left ear, which is not affected by their curvature type. Further studies are needed to investigate perceptual and cognitive asymmetry behaviour models in the auditory system in patients with AIS. CLINICAL IMPLICATIONS: Determination of perceptual and cognitive asymmetry in the auditory system may offer a new perspective on conservative treatment protocols for AIS patients. Besides, the DL paradigm can be easily used in patients with AIS as a non-invasive evaluation method in clinics.

On the characterization of cognitive tasks using activity-specific short-lived synchronization between electroencephalography channels.

Accurate characterization of brain activity during a cognitive task is challenging due to the dynamically changing and the complex nature of the brain. The majority of the proposed approaches assume stationarity in brain activity and disregard the systematic timing organization among brain regions during cognitive tasks. In this study, we propose a novel cognitive activity recognition method that captures the activity-specific timing parameters from training data that elicits maximal average short-lived pairwise synchronization between electroencephalography signals. We evaluated the characterization power of the activity-specific timing parameter triplets in a motor imagery activity recognition framework. The activity-specific timing parameter triplets consist of latency of the maximally synchronized signal segments from activity onset Δt, the time lag between maximally synchronized signal segments τ, and the duration of the maximally synchronized signal segments w. We used cosine-based similarity, wavelet bi-coherence, phase-locking value, phase coherence value, linearized mutual information, and cross-correntropy to calculate the channel synchronizations at the specific timing parameters. Recognition performances as well as statistical analyses on both BCI Competition-III dataset IVa and PhysioNet Motor Movement/Imagery dataset, indicate that the inter-channel short-lived synchronization calculated using activity-specific timing parameter triplets elicit significantly distinct synchronization profiles for different motor imagery tasks and can thus reliably be used for cognitive task recognition purposes.

Evaluation of the compliance between EEG monitoring (Bispectral IndexTM) and Ramsey Sedation Scale to measure the depth of sedation in the patients who underwent procedural sedation and analgesia in the emergency department.

BACKGROUND: This study aimed to investigate the compliance between electroencephalogram monitoring (Bispectral Index, BIS) and Ramsay Sedation Scale (RSS) to measure the depth of sedation in patients who underwent procedural sedation and analgesia (PSA) in an emergency department. This study also aimed to investigate the usefulness of this compliance for early diagnosis of complications. METHODS: A total of 54 consecutive patients during PSA in the emergency department were included in this study. The BIS and RSS scores at regular intervals and also all complications and interventions of these patients were evaluated. The compliance between the BIS and the RSS score was evaluated. The BIS scores of cases with complication and without complication were compared. RESULTS: The BIS and RSS scores exhibited a high correlation was detected between the average BIS and RSS scores at each time interval (r=-0.989, p<0.001). The BIS scores of the complicated and uncomplicated cases were different at 15 min after the procedure (p=0.019). The cases were divided into two groups according to the BIS scores <70 and ≥70; complication rates were higher in the BIS score <70 group during the procedure (p=0.037). CONCLUSION: In our study, a high correlation was detected between BIS monitoring and RSS scores. BIS monitoring for PSA can be used as a full-time, objective, and an alternative technique for person-dependent clinical scales and also as an indicator for early diagnosis of complications.

Sleep Is a Refreshing Process: An fNIRS Study.

Sleep is a very critical process that constitutes up to one third of daytime of a healthy adult. It is known to be an active period where body and brain is refreshed for the next day. It is both part of a larger cycle, i.e., circadian rhythm, and has subcsycles in it, i.e., sleep stages. Although hemodynamics of these stages have been investigated especially in the last two decades, there are still points in the hemodynamics to be illuminated especially in terms of refreshment. This study aims to investigate refreshing property of sleep in terms of sleep stages using functional near-infrared spectroscopy (fNIRS) for measuring prefrontal cortex (PFC) hemodynamics. Nine healthy subjects slept in sleep laboratories, monitored by polysomnography and fNIRS before, during, and after night sleep. REM stage had lower oxyhemoglobin (HbO) and total hemoglobin (HbT) than the other sleep stages and wakefulness. Deoxyhemoglobin (HbR) did not differ between any stages. All sleep stages and wakefulness stage at the end of the sleep had higher HbO and lower HbR than the beginning of the sleep. HbT levels did not differ between the beginning and the end of the sleep for any stages. During REM sleep, PFC seems to get lower blood supply, possibly due to increased demand in other brain regions. Regardless of the stage, PFC has higher oxygenation toward the end of sleep, indicating refreshment. Overall, our brain seems to be on duty during sleep throughout the night for "cleaning" and "refreshing" itself. Hemodynamic changes from the beginning to end of sleep might be the indicator of this work. Thus, accordingly REM stage seems to be at a central point for this work.

Deaf adolescents have bigger responses for somatosensory and visual stimulations.

The functions of the sensory systems on disabled people have been one of the most investigated topics in brain research. In these studies, mostly visual stimuli had been employed while investigating the deaf participants. Limited number of electrophysiological studies revealed better visual sensory processing in deaf participants. On the other hand, studies deploying tactile stimuli especially used either electrical or painful stimulus or they focused the psychophysical assessments of thresholds associated with tactile stimuli. The present study tried to evaluate electrophysiological brain responses in deaf and control group with a unimodal study design including both the visual and non-painful tactile stimuli, and to reveal the possible changes in brain plasticity within modality basis. Thirteen congenitally deaf adolescents (mean: 14.61 ±â€¯1.06 years; 7 girls) and 10 adolescents with normal hearing (16.6 ±â€¯2.72 years; 4 girls) were recruited for the study. Somatosensory evoked potentials (SEP) and visual evoked potentials (VEP) were separately delivered to the participants and in order to maintain neutrality among sessions they were presented in random order while the electroencephalography (EEG) recordings were taken. Brain responses to non-painful tactile and visual stimuli were measured for N1, P2, and N2 components. All amplitudes of deaf group were significantly larger than all amplitudes of control group in SEP session whereas in VEP session only P2 and N2 amplitudes of deaf group were statistically larger. In addition, the latency of N1 component in VEP session was significantly earlier in deaf group. These findings suggest early cortical excitability, less neuronal capacity usage and also more efficient sensory processing in deaf group.

Auditory brain oscillatory responses in drug-naïve patients with Parkinson's disease.

Parkinson's Disease (PD) is a common neurodegenerative disorder affecting the function of dopaminergic cells in basal ganglia. Besides the motor symptoms, tremor, and dysfunction of sensory systems. In the literature, there was limited studies which investigates the basic sensorial processing in PD. Therefore, we aimed to establish the sensorial processing of simple auditory stimulations in naïve PD comparing to healthy controls (HC) via delta, theta, and alpha brain oscillatory responses. 12 naïve PD and 12 HC participated to the study. Brain responses recorded via the 64-channel electroencephalography (EEG) system in an electromagnetically and acoustically isolated room. The auditory stimuli (1500 Hz, 60 dB SPL, 500 ms) were delivered to the subjects via a headphone. The inter-stimulus interval was ranged between 2.5-4.5 s. The peak-to-peak maximum amplitudes were measured in the delta, theta and alpha frequency bands on 11 electrodes (including the frontal, central and parietal areas) for the statistical analysis in which one-way ANOVA test was employed for the comparisons between PD and HC. For the delta oscillatory responses, PD group has bigger amplitudes in frontal, central and parietal areas in comparison with HC. For the theta and alpha oscillatory responses, PD group has bigger amplitudes in parietal areas in comparison with HC. As a result, amplitudes of brain oscillatory responses in PD group were significantly bigger than the HC. In this context, decreased inhibitory mechanisms of cortical auditory processing due to the dysfunction of the dopaminergic activity may lead the increased evoked responses in PD group.

Brain asymmetry in directing attention during dichotic listening test: An fNIRS study.

In a classical dichotic listening paradigm, besides auditory brain asymmetry, cognitive functions such as attention and conflict resolution play a major role. The aim of this study is to reveal the possible haemodynamic mechanisms of higher attentional performance in prefrontal cortex during dichotic listening test. Twenty-six healthy participants underwent a dichotic listening task in three sessions; non-forced attention, attention focused to right ear, and attention focused to left ear. In each session, haemodynamic activity of prefrontal brain area was recorded using functional near-infrared spectroscopy (fNIRS). Effects of focused attention and performance level of the task on oxy-, deoxy-, and total haemoglobin levels were investigated. Oxy- and total haemoglobin levels in right prefrontal regions during forced-right and forced-left sessions were significantly higher than levels of the non-forced session. This might be an indicator of inhibition and orienting attentional functions of right inferior frontal gyrus. High performers had significantly higher deoxyhaemoglobin levels in the forced-left session compared to the non-forced session, while low performers' deoxyhaemoglobin levels did not differ among these sessions. Observing this difference only in the forced-left session but not in the forced-right session might suggest conflict resolution in top-down and bottom-up processes during the forced-left session for right-handed participants.

The impact of musical experience on neural sound encoding performance.

In this study, 64-channel single trial auditory brain oscillations (STABO) have been firstly analyzed by using complexity metrics to observe the effect of musical experience on brain functions. Experimental data was recorded from eyes-opened volunteers during listening the musical chords by piano. Complexity estimation methods were compared to each other for classification of groups (professional musicians and non-musicians) by using both classifiers (support vector machine (SVM), Naive Bayes (NB)) and statistical tests (one-way ANOVA) with respect to electrode locations. Permutation entropy (PermEn) is found to be the best metric (p ≪ 0.0001, 98.37% and 98.41% accuracies for tonal and atonal ensembles) at fronto-temporal regions which are responsible for cognitive task evaluation and perception of sound. PermEn also provides the meaningful results at the whole cortex (p ≪ 0.0001, 99.81% accuracy for both tonal and atonal ensembles) through SVM with Radial Basis kernels superior to Gaussians. Almost the similar performance is also obtained for temporal features. Although, performance improvements are observed for spectral methods with NB, the considerable better results are obtained with SVM. The results indicate that musical stimuli cause pattern variations instead of spectral variations on STABO due to relatively higher neuronal activities around auditory cortex. In conclusion, temporal regions produce response to auditory stimuli, while frontal area integrates the auditory task at the same time. As well, the parietal cortex produces neural information according to the degree of attention generated by environmental changes such as atonal stimuli. It can be clearly stated that musical experience enhances the neural encoding performance of sound tonality at mostly fronto-temporal regions.

Acute Supramaximal Exercise Increases the Brain Oxygenation in Relation to Cognitive Workload.

Single bout of exercise can improve the performance on cognitive tasks. However, cognitive responses may be controversial due to different type, intensity, and duration of exercise. In addition, the mechanism of the effect of acute exercise on brain is still unclear. This study was aimed to investigate the effects of supramaximal exercise on cognitive tasks by means of brain oxygenation monitoring. The brain oxygenation of Prefrontal cortex (PFC) was measured on 35 healthy male volunteers via functional near infrared spectroscopy (fNIRS) system. Subjects performed 2-Back test before and after the supramaximal exercise wingate anerobic test (WAnT) lasting 30-s on cycle ergometer. The PFC oxygenation change evaluation revealed that PFC oxygenation rise during post-exercise 2-Back task was considerably higher than those in pre-exercise 2-Back task. In order to describe the relationship between oxygenation change and exercise performance, subjects were divided into two groups as high performers (HP) and low performers (LP) according to their peak power values (PP) obtained from the supramaximal test. The oxy-hemoglobin (oxy-Hb) values were compared between pre- and post-exercise conditions within subjects and also between subjects according to peak power. When performers were compared, in the HP group, the oxy-Hb values in post-exercise 2-Back test were significantly higher than those in pre-exercise 2-Back test. HP had significantly higher post-exercise oxy-Hb change (Δ) than those of LP. In addition, PP of the total group were significantly correlated with Δoxy-Hb.The key findings of the present study revealed that acute supramaximal exercise has an impact on the brain oxygenation during a cognitive task. Also, the higher the anerobic PP describes the larger the oxy-Hb response in post-exercise cognitive task. The current study also demonstrated a significant correlation between peak power (exercise load) and post-exercise hemodynamic responses (oxy-, deoxy- and total-Hb). The magnitude of this impact might be related with the physical performance capacities of the individuals. This can become a valuable parameter for future studies on human factor.

Assessing Olfactory Function in Parkinson's Disease via Entropy Analysis of Chemosensory Event Related Potentials.

The relationship between Parkinson's disease (PD) and olfactory dysfunction has been investigated via psychophysical and electrophysiological assessments. Despite the increasing number of electrophysiological studies focusing on olfactory function, there are still some limitations to observe the chemosensory event-related potentials (CSERP), which are electrophysiological responses of the brain to olfactory and trigeminal stimulations, because of the low sensitivity (low signal-to-noise ratio). Recent studies attempted to establish new techniques to increase the sensitivity for evaluating the CSERP and brain responsiveness. We aimed to inspect CSERP via entropy analysis in assessing chemosensory related brain responses that has been used for the first time. Twelve newly diagnosed and non-medicated PD patients and 12 healthy subjects participated in the study. Psychophysical and electrophysiological evaluation of olfaction were assessed via Sniffin' Sticks Test (SST) and entropy analysis on CSERP in three time windows. The scores of odor threshold, odor identification and total scores of SST were lower (hyposmic) in PD patients compared to healthy subjects. Electrophysiological assessments revealed a significant change in entropy among time windows for olfactory stimulation with phenyl ethyl alcohol and trigeminal stimulation with carbon dioxide (both p < 0.05) in healthy subjects but not in PD patients. Entropy findings indicate that the brain operates in ordered state among healthy subjects in response to olfactory/trigeminal stimuli, whereas the PD patients displayed a chaotic pattern. This pattern in the PD patients suggests the lack of proper smell function. It should be studied if this pattern can be used as a biomarker for PD.

Brain morphometry and electrophysiological recordings in relation to illness duration in schizophrenia.

Schizophrenia has been recently increasingly linked with a number of structural brain morphological changes which can be associated with functional deficiencies. The aim of this study is to relate electrophysiological changes with structural changes of Heschl's gyrus (HG) volume in schizophrenia. Fifteen schizophrenia patients were compared with control group by magnetic resonance imaging (MRI) volumetry and auditory evoked potentials. A significantly lower bilateral HG volumes and a significantly lower global field power value of the N1P2 component were detected in the schizophrenia group. The auditory evoked potentials have been used as a functional correlate that displayed a significant amplitude reduction that matched the reduction in the HG volume with the chronicity of the disease. This trend may be utilized as a vehicle to assess follow-up of the disorder by means of MRI and electrophysiology.

Auditory verbal hallucinations in schizophrenia as aberrant lateralized speech perception: evidence from dichotic listening.

We report evidence that auditory verbal hallucinations (AVH) in schizophrenia patients are perceptual distortions lateralized to the left hemisphere. We used a dichotic listening task with repeated presentations of consonant-vowel syllables, a different syllable in the right and left ear. This task produces more correct reports for the right ear syllable in healthy individuals, indicative of left hemisphere speech processing focus. If AVHs are lateralized to the left hemisphere language receptive areas, then this should interfere with correct right ear reports in the dichotic task, which would result in significant negative correlations with severity of AVHs. We correlated the right and left ear correct reports with the PANSS hallucination symptom, and a randomly selected negative symptom, in addition to the sum total of the positive and negative symptoms, in 160 patients with schizophrenia. The results confirmed the predictions with significant negative correlations for the right ear scores with the PANSS hallucination item, and for the sum total of positive symptoms, while all other correlations were close to zero. The results are unambiguous evidence for AVHs as aberrant speech perceptions originating in the left hemisphere.

Amplitude and phase-shift effects on dichotic listening performance.

OBJECTIVE: Previous dichotic listening (DL) studies have shown that interaural amplitude or phase shifts have powerful effects on dichotic ear advantage. However, it is not known how these two factors interact. The present study aims to explore this interaction when amplitude (intensity) and phase (time) shifts occur simultaneously. DESIGN: Participants listened to dichotically presented pairs of consonant-vowel syllables (216 trials) under nine different experimental conditions, systematically varying amplitude (+9 dB) and phase (+35 ms) shifts. Participants reported which syllable they perceived on each trial. STUDY SAMPLE: Thirty-two healthy adults. RESULTS: The results showed an expected right ear advantage (REA) in the baseline (nosound manipulation) condition. While amplitude shifts favoring the right ear were found to have a greater effect on REA than phase shifts, phase shifts favoring the left ear were found to have a greater effect on left ear advantage (LEA) than amplitude shifts. Furthermore, phase shifts favoring the left ear had a greater effect on LEA than phase shifts favoring the right ear on REA. CONCLUSIONS: Present results may have consequences for the training of individuals with auditory and phonetic difficulties, e.g. auditory processing deficits or dyslexia, by aiding the design of optimal combinations of acoustic and phonetic training tools.

Brain function assessment in different conscious states.

BACKGROUND: The study of brain functioning is a major challenge in neuroscience fields as human brain has a dynamic and ever changing information processing. Case is worsened with conditions where brain undergoes major changes in so-called different conscious states. Even though the exact definition of consciousness is a hard one, there are certain conditions where the descriptions have reached a consensus. The sleep and the anesthesia are different conditions which are separable from each other and also from wakefulness. The aim of our group has been to tackle the issue of brain functioning with setting up similar research conditions for these three conscious states. METHODS: In order to achieve this goal we have designed an auditory stimulation battery with changing conditions to be recorded during a 40 channel EEG polygraph (Nuamps) session. The stimuli (modified mismatch, auditory evoked etc.) have been administered both in the operation room and the sleep lab via Embedded Interactive Stimulus Unit which was developed in our lab. The overall study has provided some results for three domains of consciousness. In order to be able to monitor the changes we have incorporated Bispectral Index Monitoring to both sleep and anesthesia conditions. RESULTS: The first stage results have provided a basic understanding in these altered states such that auditory stimuli have been successfully processed in both light and deep sleep stages. The anesthesia provides a sudden change in brain responsiveness; therefore a dosage dependent anesthetic administration has proved to be useful. The auditory processing was exemplified targeting N1 wave, with a thorough analysis from spectrogram to sLORETA. The frequency components were observed to be shifting throughout the stages. The propofol administration and the deeper sleep stages both resulted in the decreasing of N1 component. The sLORETA revealed similar activity at BA7 in sleep (BIS 70) and target propofol concentration of 1.2 microg/mL. CONCLUSIONS: The current study utilized similar stimulation and recording system and incorporated BIS dependent values to validate a common approach to sleep and anesthesia. Accordingly the brain has a complex behavior pattern, dynamically changing its responsiveness in accordance with stimulations and states.