Leszek Michał Sagan

Prof. Dr. Leszek Michał Sagan


Research Focus & Metrics

Academic Career Length

8Years (2019-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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30 October 2020 in Pharmacological Reports
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PPPiotr Podwalski
Piotr Podwalski
KSKrzysztof Szczygieł
Krzysztof Szczygieł
ETErnest Tyburski
Ernest Tyburski
LSLeszek Michał Sagan
Leszek Michał Sagan
Blazej MisiakBlazej Misiak
Blazej Misiak
JSJerzy Sanochowiec
Jerzy Sanochowiec
Diffusion tensor imaging (DTI) is an imaging technique that uses magnetic resonance. It measures the diffusion of water molecules in tissues, which can occur either without restriction (i.e., in an isotropic manner) or limited by some obstacles, such as cell membranes (i.e., in an anisotropic manner). Diffusion is most often measured in terms of, inter alia, fractional anisotropy (FA), mean diffusivity (MD), radial diffusivity (RD), and axial diffusivity (AD). DTI allows us to reconstruct, visualize, and evaluate certain qualities of white matter. To date, many studies have sought to associate various changes in the distribution of diffusion within the brain with mental diseases and disorders. A better understanding of white matter integrity disorders can help us recognize the causes of diseases, as well as help create objective methods of psychiatric diagnosis, identify biomarkers of mental illness, and improve pharmacotherapy. The aim of this work is to present the characteristics of DTI as well as current research on its use in schizophrenia, affective disorders, and other mental disorders.

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ETErnest Tyburski
Ernest Tyburski
MMMonika Mak
Monika Mak
ASAndrzej Sokołowski
Andrzej Sokołowski
ASAnna Starkowska
Anna Starkowska
EKEwa Karabanowicz
Ewa Karabanowicz
AJAshok S. Jansari
Ashok S. Jansari
In recent years, interest has grown in measuring executive function in schizophrenia with ecological and virtual reality (VR) tools. However, there is a lack of critical analysis comparing those tools with traditional ones. This paper aims to characterize executive dysfunction in schizophrenia by comparing ecological and virtual reality assessments with traditional tools, and to describe the neurobiological and psychopathological correlates. The analysis revealed that ecological and VR tests have higher levels of verisimilitude and similar levels of veridicality compared to traditional tools. Both negative symptoms and disorganization correlate significantly with executive dysfunction as measured by traditional tools, but their relationships with measures based on ecological and VR methods are still unclear. Although there is much research on brain correlates of executive impairments in schizophrenia with traditional tools, it is uncertain if these results will be confirmed with the use of ecological and VR tools. In the diagnosis of executive dysfunction, it is important to use a variety of neuropsychological methods—especially those with confirmed ecological validity—to properly recognize the underlying characteristics of the observed deficits and to implement effective forms of therapy.

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KRKatarzyna Rek-Owodziń
Katarzyna Rek-Owodziń
ETErnest Tyburski
Ernest Tyburski
PPPiotr Plichta
Piotr Plichta
KWKatarzyna Waszczuk
Katarzyna Waszczuk
MBMaksymilian Bielecki
Maksymilian Bielecki
MMMonika Mak
Monika Mak
Impairments in cognitive functions are one of the main features of schizophrenia. A variety of factors can influence the extent of cognitive deficits. In our study, we examined the severity of cognitive deficits at different stages of the disease and the relationship between psychopathological symptoms and cognitive functions. We recruited 32 patients with first-episode psychosis (FEP), 70 with chronic schizophrenia (CS), and 39 healthy controls (HC). Psychopathological symptoms were evaluated with the Positive and Negative Syndrome Scale (PANSS) and cognitive functions were measured with the MATRICS Cognitive Consensus Battery (MCCB). Cognitive deficits were present in both FEP and CS participants. CS individuals had lower overall scores and poorer working memory; however, clinical variables appeared to play a significant role in these scores. In FEP, disorganization correlated negatively with verbal and visual learning and memory, social cognition, and overall score; negative symptoms negatively correlated with social cognition. In CS participants, disorganization correlated negatively with speed of processing, reasoning, problem solving, and overall score; negative symptoms were negatively correlated with speed of processing, visual learning, memory, and overall score; positive symptoms were negatively correlated with reasoning and problem solving. Our findings indicate that psychopathological symptoms have a significant impact on cognitive functions in FEP and CS patients.

Verified
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PPPiotr Podwalski
Piotr Podwalski
ETErnest Tyburski
Ernest Tyburski
KSKrzysztof Szczygieł
Krzysztof Szczygieł
KWKatarzyna Waszczuk
Katarzyna Waszczuk
KRKatarzyna Izabela Rek-Owodziń
Katarzyna Izabela Rek-Owodziń
JSJerzy Sanochowiec
Jerzy Sanochowiec
Deficit syndrome (DS) is a subtype of schizophrenia characterized by primary persistent negative symptoms. The corpus callosum (CC) appears to be related to psychopathology in schizophrenia. This study assessed white matter integrity in the CC using diffusion tensor imaging (DTI) in deficit and non-deficit schizophrenia (NDS) patients. We also investigated the psychopathological dimensions of schizophrenia and their relationship to CC integrity. Fifteen DS patients, 40 NDS patients, and 30 healthy controls (HC) underwent psychiatric evaluation and neuroimaging. We divided the CC into five regions and assessed their fractional anisotropy (FA) and mean diffusivity (MD). Psychopathology was assessed with the Positive and Negative Syndrome Scale. DS patients had lower FA than NDS patients and HC, and higher MD in Region 5 of the CC than did HC. NDS patients had higher MD in Region 4 of the CC. The patient groups differed in terms of negative symptoms. After differentiating clinical groups and HC, no significant correlations were observed between DTI measures and psychopathological symptoms. Our results suggest that DS and NDS are characterized by minor impairments of the posterior CC. We confirmed that DS patients have greater negative psychopathology than NDS patients. Our results are preliminary, and further studies are needed.

26 April 2021 in Journal of Clinical Medicine
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KSKarol Sagan
Karol Sagan
EAElżbieta Andrysiak-Mamos
Elżbieta Andrysiak-Mamos
ETErnest Tyburski
Ernest Tyburski
LSLeszek Michał Sagan
Leszek Michał Sagan
ASAnhelli Syrenicz
Anhelli Syrenicz
Objective: To determine the effect of transsphenoidal surgery on quality of life and sleep in patients with pituitary adenomas depending on tumor type and compression of the optic chiasm. Methods: In this prospective study, patients with pituitary adenomas who were scheduled for transsphenoidal surgery completed the Short Form 36 Questionnaire, Pittsburgh Sleep Quality Index, and Epworth Sleepiness Scale preoperatively and 7.5 (±1.5) months after surgery. Patients were analyzed based on tumor type and compression of the optic chiasm. Results: Significant improvements with large effect sizes were seen for patients with Cushing’s disease in general health (Z = −2.37; p = 0.018), vitality (Z = −2.05; p = 0.041), and mental health (Z = −2.06; p = 0.040). A significant deterioration with large effect size occurred in physical functioning (Z = −2.02; p = 0.043) in patients with acromegaly. A significant improvement with medium effect size was seen in subjective sleep quality, (Z = −2.24; p = 0.025), sleep duration (Z = −2.11; p = 0.035), and habitual sleep efficiency (Z = −2.26; p = 0.024) after decompression of the optic chiasm. Multiple significant correlations were observed between sleep parameters and Short Form 36 subscales before and after treatment. Conclusions: Changes in quality of life during the follow-up period depend on tumor type. Circadian rhythm disturbances may resolve promptly after decompression of the optic chiasm. Quality of life in pituitary adenoma patients is associated with quality of sleep in many dimensions, thus implying that developing strategies to improve sleep quality could increase overall well-being and everyday functioning in pituitary adenoma patients.

14 February 2022 in Brain Sciences
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Journal Article
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PPPiotr Podwalski
Piotr Podwalski
ETErnest Tyburski
Ernest Tyburski
KSKrzysztof Szczygieł
Krzysztof Szczygieł
KRKrzysztof Rudkowski
Krzysztof Rudkowski
KWKatarzyna Waszczuk
Katarzyna Waszczuk
JSJerzy Sanochowiec
Jerzy Sanochowiec
The superior longitudinal fasciculus (SLF) is a white matter bundle that connects the frontal areas with the parietal areas. As part of the visuospatial attentional network, it may be involved in the development of schizophrenia. Deficit syndrome (DS) is characterized by primary and enduring negative symptoms. The present study assessed SLF integrity in DS and nondeficit schizophrenia (NDS) patients and examined possible relationships between it and psychopathology. Twenty-six DS patients, 42 NDS patients, and 36 healthy controls (HC) underwent psychiatric evaluation and diffusion tensor imaging (DTI). After post-processing, fractional anisotropy (FA) values within the SLF were analyzed. Psychopathology was assessed with the Positive and Negative Syndrome Scale, Brief Negative Symptom Scale, and Self-evaluation of Negative Symptoms. The PANSS proxy for the deficit syndrome was used to diagnose DS. NDS patients had lower FA values than HC. DS patients had greater negative symptoms than NDS patients. After differentiating clinical groups and HC, we found no significant correlations between DTI measures and psychopathological dimensions. These results suggest that changes in SLF integrity are related to schizophrenia, and frontoparietal dysconnection plays a role in its etiopathogenesis. We confirmed that DS patients have greater negative psychopathology than NDS patients. These results are preliminary; further studies are needed.