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Papers by Zvezdan Pirtošek
Journal of Neural Transmission
Alzheimers & Dementia, Jul 1, 2017
Alzheimers & Dementia, Jul 1, 2018
significantly different between CNAß+ and EMCIAß+, but was significantly higher in CNAß+ than LMC... more significantly different between CNAß+ and EMCIAß+, but was significantly higher in CNAß+ than LMCIAß+ (p<0.001). D was significantly higher in EMCIAß+ than LMCI Aß+ (p<0.02). PC5, including visual, sensory-motor, and superior-temporal regions was associated with visuospatial and language function, while PC38, showing frontal interactions, was associated with executive function. Conclusions:Reconstructing FC with disease dependent components increases sensitivity to differences in connectivity across the AD spectrum and identifies functional subnetworks implicated in early stages of AD.
Parkinsonism & Related Disorders, Oct 1, 2020
Biomedicine hub, Nov 23, 2020
Alzheimer's disease (AD) and related dementia is one of the growing threats to the sustainability... more Alzheimer's disease (AD) and related dementia is one of the growing threats to the sustainability of health and care systems in developed countries, and efforts to find therapies have had scant success. The main reasons for this are lack of efficient therapy, which is linked to too late discovery of the disease itself. With this in mind, biomarkers are recognised as an element which can bring a major contribution to research, helping elucidate the disease and
Acta Neurologica Scandinavica, May 24, 2022
Advances in behavioral biology, 1990
Background: fMRI studies show activation of cerebellum during transcutaneous auricular vagal nerv... more Background: fMRI studies show activation of cerebellum during transcutaneous auricular vagal nerve stimulation (taVNS), however there is no evidence whether taVNS induced activation of the cerebellum translates to the cerebellar closed loops involved in motor functions. Objective/Hypothesis: We assessed the propensity of taVNS at 25Hz (taVNS25) and 100Hz (taVNS100) to modulate cerebello-thalamo-cortical pathways using transcranial magnetic stimulation. Methods: Double blind within-subjects study. 32 participants completed one visit during which cerebellar brain inhibition (CBI) was assessed at baseline (no stimulation) and in a randomized order during taVNS100, taVNS25, and sham taVNS (xVNS). Generalized linear mixed models with gamma distribution were built to assess the effect of taVNS on CBI. The estimated marginal means of linear trends during each taVNS condition were computed and compared in a pairwise fashion with Benjamini Hochbeck correction for multiple comparisons. Result...
Psychiatria Danubina, Dec 16, 2022
Background: Late onset depression is characterised by pronounced cognitive impairment, more somat... more Background: Late onset depression is characterised by pronounced cognitive impairment, more somatic complaints and psychomotor retardation. Psychomotor slowing may be due to impairment in either motor or cognitive domain. Electrophysiology may be particularly convenient as a tool in studies of psychomotor retardation, as it can separate central cognitive processing from the motor processing. Subjects and methods: In this study we compared event related potentials (ERP) in the two groups of patients with late onset depression and psychomotor slowing as measured by reaction time (RT): a group of patients with lower RT was compared to a group with a higher RT. Twenty patients with late onset depression were included in the study after they had reached remission. Four weeks after reaching remission patients were reevaluated clinically using Hamilton Depression Rating Scale, Mini Mental State Examination, and with a computer version of the Stroop task. ERP, accuracy and RTs were simultaneously recorded. Both groups of patients aditionaly underwent a perfusion SPECT imaging. Results: There were no differences between the short and long RT groups of patients in amplitudes of the late positive Stroop related potentials. The group of patients with longer RTs showed significant hyperperfusion in precentral gyrus, parietal regions, cuneus and hypoperfusion within insular, frontal, temporal and limbic (parahyppocampal gyrus and anterior cingulate) cortices, as well as cerebellum. Conclusion: We found no ERP differences between the two groups suggesting that although patients may differ on psychomotor retardation measured as RT, their cognitive abilities may be quite similar. Perfusion SPECT imaging however revealed a significant difference between them. This may be due to a process of compensation and applying different strategies to cope with cognitive impairment in the two groups.
Alzheimer's & Dementia, 2021
The increasing number of patients with neurodegenerative dementia is a major public health issue.... more The increasing number of patients with neurodegenerative dementia is a major public health issue. While clinical features of neurodegenerative disorders causing dementia are overlapping, accurate diagnosis is a prerequisite for an effective drug development. Besides the need for a better biomarker of Alzheimer’s disease (AD), development of non‐AD biomarkers is necessary. Behavioral variant of frontotemporal dementia (bvFTD) is the second most common neurodegenerative dementia in patients younger than 65 years. The aim of our study was to identify and validate bvFTD specific metabolic brain pattern using voxel‐based spatial covariance analysis according to the scaled subprofile model (SSM/PCA) on a new cohort of European patients and to study its biologic significance.
Zdravniški vestnik
Abstract Tremor is one of the most common disorders in the population of patients diagnosed with ... more Abstract Tremor is one of the most common disorders in the population of patients diagnosed with movement disorders. In the literature we find several classifications and different types of tremors. Each tremor type has its own characteristics. The most frequently used and widely accepted tremor classification divides tremors according to clinical appearance. First, they are roughly divided into resting tremor and action tremor. Action tremor is then subdivided into postural, kinetic, intention, task specific and isometric tremor. Different types of tremor are further combined into tremor syndromes. Causes and mechanisms of tremor are still unclear. Tremor genesis is explained by four hypothetical mechanisms and one of them is assumed to be dominant for each type of tremor. Correct tremor recognition and diagnosis is necessary for appropriate treatment of tremor patients.
International Journal of Geriatric Psychiatry, 2003
BackgroundReports of differential impairments on visual‐construction tasks in dementia with Lewy ... more BackgroundReports of differential impairments on visual‐construction tasks in dementia with Lewy bodies (DLB) and Alzheimer's disease (AD) are sometimes controversial, whereas visual‐perceptual data are lacking. The existence of different clinical sub‐groups of DLB has been hypothesized to explain the discrepancies among the cognitive results. The goal of this study was to compare the visual‐perceptual performance of subjects with DLB with predominant psychosis, DLB with predominant parkinsonian features and AD.MethodsThis is a cross‐sectional neuropsychological study with between diagnostic group comparisons. The Benton Judgement Line Orientation (BJLO) test was administered to four DLB patients with predominant psychosis (DLB‐psy), four DLB subjects with predominant parkinsonian features (DLB‐PD), and 13 patients with AD. An analysis of error types was applied to the results of the BJLO with QO1, QO2, QO3, QO4 (visual attention) errors, as well as VH, IQO, IQOV, and IQOH (visu...
Alzheimer's & Dementia
HAL is a multidisciplinary open access archive for the deposit and dissemination of scientific re... more HAL is a multidisciplinary open access archive for the deposit and dissemination of scientific research documents, whether they are published or not. The documents may come from teaching and research institutions in France or abroad, or from public or private research centers. L'archive ouverte pluridisciplinaire HAL, est destinée au dépôt et à la diffusion de documents scientifiques de niveau recherche, publiés ou non, émanant des établissements d'enseignement et de recherche français ou étrangers, des laboratoires publics ou privés.
The Cerebellum
fMRI studies show activation of cerebellum during transcutaneous auricular vagal nerve stimulatio... more fMRI studies show activation of cerebellum during transcutaneous auricular vagal nerve stimulation (taVNS); however, there is no evidence whether taVNS induced activation of the cerebellum translates to the cerebellar closed loops involved in motor functions. We assessed the propensity of taVNS at 25 Hz (taVNS25) and 100 Hz (taVNS100) to modulate cerebello-thalamo-cortical pathways using transcranial magnetic stimulation. In our double blind within-subjects study thirty-two participants completed one visit during which cerebellar brain inhibition (CBI) was assessed at baseline (no stimulation) and in a randomized order during taVNS100, taVNS25, and sham taVNS (xVNS). Generalized linear mixed models with gamma distribution were built to assess the effect of taVNS on CBI. The estimated marginal means of linear trends during each taVNS condition were computed and compared in a pairwise fashion with Benjamini-Hochberg correction for multiple comparisons. CBI significantly increased duri...
Journal of Neural Transmission
Alzheimers & Dementia, Jul 1, 2017
Alzheimers & Dementia, Jul 1, 2018
significantly different between CNAß+ and EMCIAß+, but was significantly higher in CNAß+ than LMC... more significantly different between CNAß+ and EMCIAß+, but was significantly higher in CNAß+ than LMCIAß+ (p<0.001). D was significantly higher in EMCIAß+ than LMCI Aß+ (p<0.02). PC5, including visual, sensory-motor, and superior-temporal regions was associated with visuospatial and language function, while PC38, showing frontal interactions, was associated with executive function. Conclusions:Reconstructing FC with disease dependent components increases sensitivity to differences in connectivity across the AD spectrum and identifies functional subnetworks implicated in early stages of AD.
Parkinsonism & Related Disorders, Oct 1, 2020
Biomedicine hub, Nov 23, 2020
Alzheimer's disease (AD) and related dementia is one of the growing threats to the sustainability... more Alzheimer's disease (AD) and related dementia is one of the growing threats to the sustainability of health and care systems in developed countries, and efforts to find therapies have had scant success. The main reasons for this are lack of efficient therapy, which is linked to too late discovery of the disease itself. With this in mind, biomarkers are recognised as an element which can bring a major contribution to research, helping elucidate the disease and
Acta Neurologica Scandinavica, May 24, 2022
Advances in behavioral biology, 1990
Background: fMRI studies show activation of cerebellum during transcutaneous auricular vagal nerv... more Background: fMRI studies show activation of cerebellum during transcutaneous auricular vagal nerve stimulation (taVNS), however there is no evidence whether taVNS induced activation of the cerebellum translates to the cerebellar closed loops involved in motor functions. Objective/Hypothesis: We assessed the propensity of taVNS at 25Hz (taVNS25) and 100Hz (taVNS100) to modulate cerebello-thalamo-cortical pathways using transcranial magnetic stimulation. Methods: Double blind within-subjects study. 32 participants completed one visit during which cerebellar brain inhibition (CBI) was assessed at baseline (no stimulation) and in a randomized order during taVNS100, taVNS25, and sham taVNS (xVNS). Generalized linear mixed models with gamma distribution were built to assess the effect of taVNS on CBI. The estimated marginal means of linear trends during each taVNS condition were computed and compared in a pairwise fashion with Benjamini Hochbeck correction for multiple comparisons. Result...
Psychiatria Danubina, Dec 16, 2022
Background: Late onset depression is characterised by pronounced cognitive impairment, more somat... more Background: Late onset depression is characterised by pronounced cognitive impairment, more somatic complaints and psychomotor retardation. Psychomotor slowing may be due to impairment in either motor or cognitive domain. Electrophysiology may be particularly convenient as a tool in studies of psychomotor retardation, as it can separate central cognitive processing from the motor processing. Subjects and methods: In this study we compared event related potentials (ERP) in the two groups of patients with late onset depression and psychomotor slowing as measured by reaction time (RT): a group of patients with lower RT was compared to a group with a higher RT. Twenty patients with late onset depression were included in the study after they had reached remission. Four weeks after reaching remission patients were reevaluated clinically using Hamilton Depression Rating Scale, Mini Mental State Examination, and with a computer version of the Stroop task. ERP, accuracy and RTs were simultaneously recorded. Both groups of patients aditionaly underwent a perfusion SPECT imaging. Results: There were no differences between the short and long RT groups of patients in amplitudes of the late positive Stroop related potentials. The group of patients with longer RTs showed significant hyperperfusion in precentral gyrus, parietal regions, cuneus and hypoperfusion within insular, frontal, temporal and limbic (parahyppocampal gyrus and anterior cingulate) cortices, as well as cerebellum. Conclusion: We found no ERP differences between the two groups suggesting that although patients may differ on psychomotor retardation measured as RT, their cognitive abilities may be quite similar. Perfusion SPECT imaging however revealed a significant difference between them. This may be due to a process of compensation and applying different strategies to cope with cognitive impairment in the two groups.
Alzheimer's & Dementia, 2021
The increasing number of patients with neurodegenerative dementia is a major public health issue.... more The increasing number of patients with neurodegenerative dementia is a major public health issue. While clinical features of neurodegenerative disorders causing dementia are overlapping, accurate diagnosis is a prerequisite for an effective drug development. Besides the need for a better biomarker of Alzheimer’s disease (AD), development of non‐AD biomarkers is necessary. Behavioral variant of frontotemporal dementia (bvFTD) is the second most common neurodegenerative dementia in patients younger than 65 years. The aim of our study was to identify and validate bvFTD specific metabolic brain pattern using voxel‐based spatial covariance analysis according to the scaled subprofile model (SSM/PCA) on a new cohort of European patients and to study its biologic significance.
Zdravniški vestnik
Abstract Tremor is one of the most common disorders in the population of patients diagnosed with ... more Abstract Tremor is one of the most common disorders in the population of patients diagnosed with movement disorders. In the literature we find several classifications and different types of tremors. Each tremor type has its own characteristics. The most frequently used and widely accepted tremor classification divides tremors according to clinical appearance. First, they are roughly divided into resting tremor and action tremor. Action tremor is then subdivided into postural, kinetic, intention, task specific and isometric tremor. Different types of tremor are further combined into tremor syndromes. Causes and mechanisms of tremor are still unclear. Tremor genesis is explained by four hypothetical mechanisms and one of them is assumed to be dominant for each type of tremor. Correct tremor recognition and diagnosis is necessary for appropriate treatment of tremor patients.
International Journal of Geriatric Psychiatry, 2003
BackgroundReports of differential impairments on visual‐construction tasks in dementia with Lewy ... more BackgroundReports of differential impairments on visual‐construction tasks in dementia with Lewy bodies (DLB) and Alzheimer's disease (AD) are sometimes controversial, whereas visual‐perceptual data are lacking. The existence of different clinical sub‐groups of DLB has been hypothesized to explain the discrepancies among the cognitive results. The goal of this study was to compare the visual‐perceptual performance of subjects with DLB with predominant psychosis, DLB with predominant parkinsonian features and AD.MethodsThis is a cross‐sectional neuropsychological study with between diagnostic group comparisons. The Benton Judgement Line Orientation (BJLO) test was administered to four DLB patients with predominant psychosis (DLB‐psy), four DLB subjects with predominant parkinsonian features (DLB‐PD), and 13 patients with AD. An analysis of error types was applied to the results of the BJLO with QO1, QO2, QO3, QO4 (visual attention) errors, as well as VH, IQO, IQOV, and IQOH (visu...
Alzheimer's & Dementia
HAL is a multidisciplinary open access archive for the deposit and dissemination of scientific re... more HAL is a multidisciplinary open access archive for the deposit and dissemination of scientific research documents, whether they are published or not. The documents may come from teaching and research institutions in France or abroad, or from public or private research centers. L'archive ouverte pluridisciplinaire HAL, est destinée au dépôt et à la diffusion de documents scientifiques de niveau recherche, publiés ou non, émanant des établissements d'enseignement et de recherche français ou étrangers, des laboratoires publics ou privés.
The Cerebellum
fMRI studies show activation of cerebellum during transcutaneous auricular vagal nerve stimulatio... more fMRI studies show activation of cerebellum during transcutaneous auricular vagal nerve stimulation (taVNS); however, there is no evidence whether taVNS induced activation of the cerebellum translates to the cerebellar closed loops involved in motor functions. We assessed the propensity of taVNS at 25 Hz (taVNS25) and 100 Hz (taVNS100) to modulate cerebello-thalamo-cortical pathways using transcranial magnetic stimulation. In our double blind within-subjects study thirty-two participants completed one visit during which cerebellar brain inhibition (CBI) was assessed at baseline (no stimulation) and in a randomized order during taVNS100, taVNS25, and sham taVNS (xVNS). Generalized linear mixed models with gamma distribution were built to assess the effect of taVNS on CBI. The estimated marginal means of linear trends during each taVNS condition were computed and compared in a pairwise fashion with Benjamini-Hochberg correction for multiple comparisons. CBI significantly increased duri...