Relation between task-related activity modulation and cortical inhibitory function in schizophrenia and healthy controls: a TMS-EEG study.

Schizophrenia has been associated with a reduced task-related modulation of cortical activity assessed through electroencephalography (EEG). However, to the best of our knowledge, no study so far has assessed the underpinnings of this decreased EEG modulation in schizophrenia. A possible substrate of these findings could be a decreased inhibitory function, a replicated finding in the field. In this pilot study, our aim was to explore the association between EEG modulation during a cognitive task and the inhibitory system function in vivo in a sample including healthy controls and patients with schizophrenia. We hypothesized that the replicated decreased task-related activity modulation during a cognitive task in schizophrenia would be related to a hypofunction of the inhibitory system. For this purpose, 27 healthy controls and 22 patients with schizophrenia (including 13 first episodes) performed a 3-condition auditory oddball task from which the spectral entropy modulation was calculated. In addition, cortical reactivity-as an index of the inhibitory function-was assessed by the administration of 75 monophasic transcranial magnetic stimulation single pulses over the left dorsolateral prefrontal cortex. Our results replicated the task-related cortical activity modulation deficit in schizophrenia patients. Moreover, schizophrenia patients showed higher cortical reactivity following transcranial magnetic stimulation single pulses over the left dorsolateral prefrontal cortex compared to healthy controls. Cortical reactivity was inversely associated with EEG modulation, supporting the idea that a hypofunction of the inhibitory system could hamper the task-related modulation of EEG activity.

Corollary Discharge Dysfunction as a Possible Substrate of Anomalous Self-experiences in Schizophrenia.

BACKGROUND AND HYPOTHESIS: Corollary discharge mechanism suppresses the conscious auditory sensory perception of self-generated speech and attenuates electrophysiological markers such as the auditory N1 Event-Related Potential (ERP) during Electroencephalographic (EEG) recordings. This phenomenon contributes to self-identification and seems to be altered in people with schizophrenia. Therefore, its alteration could be related to the anomalous self-experiences (ASEs) frequently found in these patients. STUDY DESIGN: To analyze corollary discharge dysfunction as a possible substrate of ASEs, we recorded EEG ERP from 43 participants with schizophrenia and 43 healthy controls and scored ASEs with the 'Inventory of Psychotic-Like Anomalous Self-Experiences' (IPASE). Positive and negative symptoms were also scored with the 'Positive and Negative Syndrome Scale for Schizophrenia' (PANSS) and with the 'Brief Negative Symptom Scale' (BNSS) respectively. The N1 components were elicited by two task conditions: (1) concurrent listening to self-pronounced vowels (talk condition) and (2) subsequent non-concurrent listening to the same previously self-uttered vowels (listen condition). STUDY RESULTS: The amplitude of the N1 component elicited by the talk condition was lower compared to the listen condition in people with schizophrenia and healthy controls. However, the difference in N1 amplitude between both conditions was significantly higher in controls than in schizophrenia patients. The values of these differences in patients correlated significantly and negatively with the IPASE, PANSS, and BNSS scores. CONCLUSIONS: These results corroborate previous data relating auditory N1 ERP amplitude with altered corollary discharge mechanisms in schizophrenia and support corollary discharge dysfunction as a possible underpinning of ASEs in this illness.

Corollary discharge function in healthy controls: Evidence about self-speech and external speech processing.

As we speak, corollary discharge mechanisms suppress the auditory conscious perception of the self-generated voice in healthy subjects. This suppression has been associated with the attenuation of the auditory N1 component. To analyse this corollary discharge phenomenon (agency and ownership), we registered the event-related potentials of 42 healthy subjects. The N1 and P2 components were elicited by spoken vowels (talk condition; agency), by played-back vowels recorded with their own voice (listen-self condition; ownership) and by played-back vowels recorded with an external voice (listen-other condition). The N1 amplitude elicited by the talk condition was smaller compared with the listen-self and listen-other conditions. There were no amplitude differences in N1 between listen-self and listen-other conditions. The P2 component did not show differences between conditions. Additionally, a peak latency analysis of N1 and P2 components between the three conditions showed no differences. These findings corroborate previous results showing that the corollary discharge mechanisms dampen sensory responses to self-generated speech (agency experience) and provide new neurophysiological evidence about the similarities in the processing of played-back vowels with our own voice (ownership experience) and with an external voice.

Electroencephalography for the Study of the Auditory P300 Evoked Potential and Derived Measurements.

Electroencephalography (EEG) is a widely used tool in neuropsychiatry research. The most used measurements in EEG are the amplitude and latency of the cortical electrophysiological activity in response to stimulus, known as evoked potentials. Besides potentials, time/frequency analysis is also used to obtain information on global fluctuations of the recordings, which evoked potentials do not provide. Time/frequency analysis results in different values known as derived measures. In this work, a brief introduction to evoked potentials and time/frequency analyses in schizophrenia is given, focusing on P300, noise power, and spectral entropy. Finally, a detailed description is given on how to obtain EEG recordings, evoked potentials, and derived measures.

Real-life outcomes in biotypes of psychotic disorders based on neurocognitive performance.

Aiming at discerning potential biotypes within the psychotic syndrome, we have recently reported the possible existence of two clusters or biotypes across schizophrenia and bipolar disorder characterized by their cognitive performance using the Brief Assessment of Cognition in Schizophrenia (BACS) instrument and validated with independent biological and clinical indexes (Fernández-Linsenbarth et al. in Schizophr Res 229:102-111, 2021). In this previous work, the group with larger cognitive deficits (N = 93, including 69 chronic schizophrenia, 17 first episodes (FE) of schizophrenia and 7 bipolar disorder patients) showed smaller thalamus and hippocampus volume and hyper-synchronic electroencephalogram than the group with milder deficits (N = 105, including 58 chronic schizophrenia, 25 FE and 22 bipolar disorder patients). We predicted that if these biotypes indeed corresponded to different cognitive and biological substrates, their adaptation to real life would be different. To this end, in the present work we have followed up the patients' population included in that work at 1st and 3rd years after the date of inclusion in the 2021 study and we report on the statistical comparisons of each clinical and real-life outcomes between them. The first cluster, with larger cognitive deficits and more severe biological alterations, showed during that period a decreased capacity for job tenure (1st and 3rd years), more admissions to a psychiatric ward (1st year) and a higher likelihood for quitting psychiatric follow-up (3rd year). Patients in the second cluster, with moderate cognitive deficits, were less compliant with prescribed treatment at the 3rd year. The differences in real-life outcomes may give additional external validity to that yielded by biological measurements to the described biotypes based on neurocognition.

Default mode network components and its relationship with anomalous self-experiences in schizophrenia: A rs-fMRI exploratory study.

Anomalous self-experiences (ASEs) in schizophrenia have been under research for the last 20 years. However, no neuroimage studies have provided insight of the possible biological underpinning of ASEs. In this novel approach, the connectivity within the default mode network, calculated through a ROI-based analysis of functional magnetic resonance imaging data, was correlated to the ASEs scores assessed by the Inventory of Psychotic-Like Anomalous Self-Experiences (IPASE) in a sample of 22 schizophrenia patients. The Pearson's correlation coefficients between IPASE scores and intrahemispheric connectivity of the parahippocampal gyrus with the isthmus cingulate cortex in both hemispheres, and right parahippocampal gyrus with the right rostral anterior cingulate cortex were positive and significant suggesting a relation between hyperactive functional connectivity and anomalous self-experiences intensity. Prior literature reported these areas to have a role in self-processing and consciousness as well as being anatomically connected. Further research with larger sample size and comparison with controls are needed to confirm the relationship of this connectivity with anomalous self-experiences.

Search for schizophrenia and bipolar biotypes using functional network properties.

INTRODUCTION: Recent studies support the identification of valid subtypes within schizophrenia and bipolar disorder using cluster analysis. Our aim was to identify meaningful biotypes of psychosis based on network properties of the electroencephalogram. We hypothesized that these parameters would be more altered in a subgroup of patients also characterized by more severe deficits in other clinical, cognitive, and biological measurements. METHODS: A clustering analysis was performed using the electroencephalogram-based network parameters derived from graph-theory obtained during a P300 task of 137 schizophrenia (of them, 35 first episodes) and 46 bipolar patients. Both prestimulus and modulation of the electroencephalogram were included in the analysis. Demographic, clinical, cognitive, structural cerebral data, and the modulation of the spectral entropy of the electroencephalogram were compared between clusters. Data from 158 healthy controls were included for further comparisons. RESULTS: We identified two clusters of patients. One cluster presented higher prestimulus connectivity strength, clustering coefficient, path-length, and lower small-world index compared to controls. The modulation of clustering coefficient and path-length parameters was smaller in the former cluster, which also showed an altered structural connectivity network and a widespread cortical thinning. The other cluster of patients did not show significant differences with controls in the functional network properties. No significant differences were found between patients´ clusters in first episodes and bipolar proportions, symptoms scores, cognitive performance, or spectral entropy modulation. CONCLUSION: These data support the existence of a subgroup within psychosis with altered global properties of functional and structural connectivity.

Estudio descriptivo de los trabajadores de servicios sanitarios de una dirección de atención primaria confinados por Covid-19 / Descriptive study of the health service workers of a Primary Care Department confined by Covid-19

OBJETIVO: La pandemia de la Covid-19 está poniendo a prueba la resistencia de los sistemas sanitarios. La preservación de los profesionales sanitarios es prioritaria siempre y especialmente ante situaciones de este tipo. La exposición de los profesionales frente a contactos sospechosos obliga en muchas ocasiones a su confinamiento. El objetivo fue conocer las características epidemiológicas de los profesionales de atención primaria que han precisado confinamiento. MÉTODOS: La investigación se llevó a cabo en el área de atención primaria Metropolitana Nord de Barcelona, desde el 17 de febrero al 3 de mayo de 2020. Participaron 1.418 profesionales que requirieron confinamiento debido a la epidemia por la Covid-19. Se registraron los motivos de confinamiento, sintomatología, tiempo de confinamiento y resultados de las pruebas PCR. Se realizó análisis descriptivo univariante. RESULTADOS: El 78,8% de los profesionales eran mujeres y la edad media de fue 45,2 años. El 67,8% fueron facultativos y enfermeras, en el 32,2% restante había diferentes profesionales asistenciales y no asistenciales. El 64,1% de la muestra presentó sintomatología compatible con Covid-19. Los participantes describieron múltiples síntomas durante el confinamiento. Se realizaron 1.050 pruebas diagnósticas RT-PCR resultando positivas en 323 casos, de los que 33 fueron en personas asintomáticas. CONCLUSIONES: El impacto de la epidemia por Covid-19 se adelanta en el personal sanitario respecto a la población general. La distribución de síntomas en profesionales sanitarios es similar a la de otros estudios en población general. Del total de profesionales que precisan confinamiento en el 22,7% se confirma el diagnóstico

OBJECTIVE: The Covid-19 pandemic is testing the resistance of health systems, the preservation of health professionals is a priority in processes of this type. The professionals' exposure to suspicious contacts often requires their confinement. The objective was to know the epidemiological characteristics of the primary care professionals who required confinement. METHODS: The research was carried out in the North Metropolitan Primary Care Area of Barcelona, from February 17 to May 3, 2020. 1,418 professionals who required confinement due to the epidemic by Covid-19 participated. The reasons for confinement, symptomatology, the confinement time and the results of PCR tests results were recorded. Univariate descriptive analysis was performed. RESULTS: 78.8% of the professionals were women and the mean age was 45.2 years. 67.8% were doctors and nurses, in the remaining 32.2% there were different healthcare and non-care professionals. 64.1% of the sample presented symptoms compatible with Covid-19. Participants described multiple symptoms during confinement. 1,050 diagnostic RT- PCR tests were performed, being positive in 323 cases, of which 33 were in asymptomatic people. CONCLUSIONS: The impact of the epidemic by Covid-19 is anticipated in health personnel compared to the general population. The distribution of symptoms in healthcare professionals is similar to that of other studies in the general population. Of the total number of professionals requiring isolation, 22.7% confirmed the diagnosis

Parahemofilia (déficit congénito de factor V): informe de un caso / Parahemophilia (congenital absence of blood coagulation factor V). Report of a case

Se presenta el caso de una paciente con déficit congénito de factor V con tiempo de sangramiento, tiempo de coagulación, tiempo de protrombina, TPT y generación, alterados, con niveles de factor V disminuidos en el plasma. La epistaxis constituyó el hallazgo predominante. El estudio familiar realizado hasta el momento actual es normal. El caso de la paciente presentado en este trabajo puede tratarse de uno aislado(AU)