Relationship between neurological and cerebellar soft signs, and implicit motor learning in schizophrenia and bipolar disorder

BACKGROUND

Schizophrenia (SZ) and bipolar disorder (BD) patients share deficits in motor functions in the form of neurological (NSS) and cerebellar soft signs (CSS), and implicit motor learning disturbances. Here, we use cluster analysis method to assess (1) the relationship between those abnormalities in SZ and BD and (2) the differences between those groups.

METHODS

33 SZ patients, 33 BD patients as well as 31 healthy controls (HC) took part in the study. We assessed CSS with the International Cooperative Ataxia Rating Scale (ICARS) and NSS with the Neurological Evaluation Scale (NES). Implicit motor learning was evaluated with the Serial Reaction Time Task (SRTT). Participants were divided into clusters (Ward's method) based on the mean response time and mean error rate in SRTT. The difference in ICARS and NES scores, and SRTT variables between clusters were evaluated. We have measured associations between SRTT parameters and both ICARS and NES total scores and subscores.

RESULTS

Cluster analysis based on the SRTT parameters allowed to extract three clusters. Those were characterized by the increasing disruption of motor functioning (psychomotor retardation, the severity of NSS and CSS) regardless of the diagnosis. Cluster 1 covered almost all of HC and was characterized by faster reaction times and small number of errors. BD and SZ patients represented in cluster 1, although fully functional in performing the SRTT, showed higher rates of NSS and CSS. Patients with BD and SZ were set apart in clusters 2 and 3 in a similar proportion. Cluster 2 presented significantly slower reaction times but with the comparable number of errors to cluster 1. Cluster 3 consisted of participants with normal or decreased reaction time and significantly increased number of errors. None of the clusters were predominantly composed of the patients representing one psychiatric diagnosis.

CONCLUSIONS

To our best knowledge, we are presenting the first data indicating the relationship between implicit motor learning and NSS and CSS in SZ and BD patients' groups. Lack of clusters predominantly represented by patients with the diagnosis of SZ or BD may refer to the model of schizophrenia-bipolar disorder boundary, pointing out the similarities between those two disorders.

Time-Frequency Characterization of Resting Brain in Bipolar Disorder during Euthymia-A Preliminary Study

The goal of this paper is to investigate the baseline brain activity in euthymic bipolar disorder (BD) patients by comparing it to healthy controls (HC) with the use of a variety of resting state functional magnetic resonance imaging (rs-fMRI) analyses, such as amplitude of low frequency fluctuations (ALFF), fractional ALFF (f/ALFF), ALFF-based functional connectivity (FC), and r egional homogeneity (ReHo). We hypothesize that above-mentioned techniques will differentiate BD from HC indicating dissimilarities between the groups within different brain structures. Forty-two participants divided into two groups of euthymic BD patients (n = 21) and HC (n = 21) underwent rs-fMRI evaluation. Typical band ALFF, slow-4, slow-5, f/ALFF, as well as ReHo indexes were analyzed. Regions with altered ALFF were chosen as ROI for seed-to-voxel analysis of FC. As opposed to HC, BD patients revealed: increased ALFF in left insula; increased slow-5 in left middle temporal pole; increased f/ALFF in left superior frontal gyrus, left superior temporal gyrus, left middle occipital gyrus, right putamen, and bilateral thalamus. There were no significant differences between BD and HC groups in slow-4 band. Compared to HC, the BD group presented higher ReHo values in the left superior medial frontal gyrus and lower ReHo values in the right supplementary motor area. FC analysis revealed significant hyper-connectivity within the BD group between left insula and bilateral middle frontal gyrus, right superior parietal gyrus, right supramarginal gyrus, left inferior parietal gyrus, left cerebellum, and left supplementary motor area. To our best knowledge, this is the first rs-fMRI study combining ReHo, ALFF, f/ALFF, and subdivided frequency bands (slow-4 and slow-5) in euthymic BD patients. ALFF, f/ALFF, slow-5, as well as REHO analysis revealed significant differences between two studied groups. Although results obtained with the above methods enable to identify group-specific brain structures, no overlap between the brain regions was detected. This indicates that combination of foregoing rs-fMRI methods may complement each other, revealing the bigger picture of the complex resting state abnormalities in BD.

Altered Functional Connectivity Differences in Salience Network as a Neuromarker of Suicide Risk in Euthymic Bipolar Disorder Patients

Objective

The occurrence of death by suicide in patients diagnosed with bipolar disorder is as much as 60 times greater than in the general population. Even during the state of euthymia patients are characterized by suicide risk. The aim of the study is to investigate the baseline brain activity in euthymic bipolar disorder patients in regard to suicide risk. We hypothesized that patients compared to healthy control group will demonstrate altered functional connectivity among resting state networks which will be directly related to current suicide risk.

Method

41 subjects were enrolled in the study consisting control group (n = 21) and euthymic bipolar disorder patients group (n = 20). Functional magnetic resonance imaging was used to evaluate resting state brain activity and ROI-ROI functional connectivity analysis was performed. Suicidal risk was estimated using The Suicide Behaviors Questionnaire-Revised.

Results

A two sample t-test revealed decreased functional connectivity between regions involved in the salience network in patients compared to the control group. This decrease was negatively correlated with current suicide risk.

Conclusion

Obtained results suggest the association between risk of suicide and activity of regions responsible for functions such as learning from mistakes, prospective thinking, and sensory integration.

Altered functional connectivity among frontal eye fields, thalamus and cerebellum in bipolar disorder

OBJECTIVES

The aim of our study is to evaluate functional connectivity of cerebellothalamo-cortical networks linking frontal eye fields (FEF) and cerebellar regions associated with oculomotor control: nodulus (X), uvula (IX), flocculus (H X) and ventral paraflocculus (H IX) in bipolar disorder (BD) with the use of resting state functional magnetic resonance imaging (rsfMRI).

METHODS

19 euthymic BD patients and 14 healthy controls underwent rsfMRI examination. Functional connectivity between bilateral FEF, thalamus and cerebellar regions associated with oculomotor control was evaluated.

RESULTS

BD patients revealed decreased functional connectivity between following structures: right FEF and bilateral thalamus, flocculus (H X), uvula (IX); right thalamus and right FEF; between right flocculus (H X) and right FEF, left thalamus; between left thalamus and bilateral FEF and right flocculus (H X).

CONCLUSIONS

BD patients presented decreased functional connectivity among FEF, thalamus and cerebellar structures associated with eye movements control. Oculomotor evaluation of BD patients assessed with rsfMRI may help to determine whether altered functional connectivity observed in our study is associated with eye movements deficits in BD.

Vergence eye movements in bipolar disorder

OBJECTIVES

With respect to bipolar disorder (BD), previous research have demonstrated saccadic eye movements abnormalities, manifested mainly as an increase in reaction time (latency) in both prosaccadic and antisaccadic task. So far, there were no studies related to vergence eye movements in subjects with BD. Our primary aim was to evaluate vergence tracking performance in this clinical group.

METHODS

30 patients with BD in remission and 23 healthy controls were enrolled. Subjects underwent optometric examination where near point of convergence was measured by the use of Wolff Wand. Instrumented convergence measurements were performed using infrared eye tracker and dedicated vergence stimuli generator.

RESULTS

BD patients presented significantly higher average error between eyes' convergence and convergence required to fixate the target and higher number of saccadic intrusions compared with healthy controls group. Principal component analysis performed on oculometric parameters revealed differences between BD patients and healthy controls. Significant correlations between the vergence disturbances and saccadic intrusions were found.

CONCLUSIONS

BD patients showed the alterations of the vergence eye movements similar to the disturbances of eye movements in the fronto-parallel plane. While the abnormalities of vergence eye movements in some mental disorders have been reported, we have for the first time objectively measured this phenomenon in BD.

Burnout and neurotic symptoms among medical students

Introduction

Medical studies are considered one of the most stressful majors and the medical profession is one of the most at risk of burnout. Some studies indicate the presence of symptoms of burnout already in the early stages of career, or even before it started, i.e. during studies preparing for the profession. Medical studies may be such a case and it can affect the mental health deterioration and cause the occurrence of both burnout and neurotic symptoms.

Objectives

Assessment of the impact of the course of studies on mental health of students and the risk of rapid burnout.

Aim

Estimation of the prevalence and severity of burnout and neurotic symptoms among medical student depending on the year of study.

Methods

Seven hundred and eighty-one medical students participated in the study. We used translated version of Maslach Burnout Inventory-Student Survey and Polish questionnaire – Symptom checklist S-III – for neurotic symptoms assessment.

Results

There was no significant difference in MBI-SS subscales and symptoms checklist between first and last year of studies. Difference turned out to be significant when 1st and 6th year students with 3rd year – in Symptom checklist (P < 0.01 and P < 0.05, respectively), MBI-SS emotional exhaustion subscale (P < 0.01 for both) and depersonalization subscale (P < 0.01, significant only when compared with 1st year students).

Conclusions

Study revealed interesting pattern of burnout and neurotic symptoms, with theirs greatest severity at the beginning and the end of studies.

Disclosure of interest

The authors have not supplied their declaration of competing interest.

Mental rotation task in bipolar disorder

OBJECTIVES

Bipolar disorder (BD) significantly affects level of cognitive and motor functioning. Studies on cognitive function in BD shows i.a. deficits in visuospatial processing and visuospatial memory. However, studies have not used Mental Rotation Task to evaluate these functions so far. Our aim is to introduce this method to assess abovementioned deficits in euthymic BD patients.

METHODS

31 euthymic BD patients and 27 healthy volunteers matched for age and years of education were recruited. All participants performed digital version of Mental Rotation Task. In this task, participants were asked to compare two figures rotated against each other and declare its similarity or difference indicating whether the figures are identical or whether they constitute their own mirror image.

RESULTS

The test revealed significantly longer reaction times in the group of BD patients when images were rotated by - 90, - 45, 45, 90 degrees, or not rotated at all. There was no significant difference in condition of - 135, 135 or 180 degrees. The accuracy rate was significantly lower in the patient group than in the control group for the entire test and in each condition. The correlation between the average response time and the accuracy rate turned out to be insignificant.

CONCLUSIONS

Our results are consistent with studies presenting visuospatial deficits in bipolar disorder. In this study we show for the first time that mental rotation deficits are present in euthymic state of BD patients.

The role of affective temperaments assessed by the Temperament Evaluation of Memphis, Pisa and San Diego-Autoquestionnaire (TEMPS-A) in the relationship between morningness-eveningness and bipolarity

BACKGROUND

Growing number of studies indicates a link between eveningness chronotype, affective temperaments and bipolarity, both in patients with mood disorders and in general population. Given these tripartite associations, we hypothesized that the effect of circadian preferences on the bipolarity may be mediated by the temperamental traits.

METHODS

The study included 1449 subjects (402 men and 1047 women). They all fulfilled a web-based questionnaire, consisting of the Composite Scale of Morningness (CSM), Mood Disorder Questionnaire (MDQ), Hypomania Checklist-32 (HCL-32) and the Temperament Evaluation of the Memphis, Pisa and San Diego-Autoquestionnaire (TEMPS-A). The role of temperamental traits in the relationship between morningness-eveningness and bipolarity was assessed using mediation analysis.

RESULTS

Morningness is correlated with lower bipolarity measured by the MDQ and HCL-32, and to lower scores of depressive, cyclothymic, irritable and anxious temperaments of the TEMPS-A. There is no significant association between morningness and hyperthymic traits. Cyclothymic and irritable traits are full mediators of the association between chronotype and bipolarity, influencing bipolarity independently from circadian preferences. Depressive and anxious traits are partial mediators of this association, increasing the effect of eveningness on bipolarity.

LIMITATIONS

The indirectness of the findings in the web-based study and disproportion of participants' gender.

CONCLUSIONS

Our study confirmed that eveningness is associated with bipolarity. In case of depressive and anxious temperaments, bipolarity is associated stronger with eveningness than with the TEMPS-A scores. On the other hand, cyclothymic and irritable temperaments were associated with bipolarity independently from circadian preferences.

Disrupted implicit motor sequence learning in schizophrenia and bipolar disorder revealed with ambidextrous Serial Reaction Time Task

BACKGROUND

Impairment of implicit motor sequence learning was shown in schizophrenia (SZ) and, most recently, in bipolar disorder (BD), and was connected to cerebellar abnormalities. The goal of this study was to compare implicit motor sequence learning in BD and SZ.

METHODS

We examined 33 patients with BD, 33 patients with SZ and 31 healthy controls with a use of ambidextrous Serial Reaction Time Task (SRTT), which allows exploring asymmetries in performance depending on the hand used.

RESULTS

BD and SZ patients presented impaired implicit motor sequence learning, although the pattern of their impairments was different. While BD patients showed no signs of implicit motor sequence learning for both hands, the SZ group presented some features of motor learning when performing with the right, but not with the left hand.

CONCLUSIONS

To our best knowledge this is the first study comparing implicit motor sequence learning in BD and SZ. We show that both diseases share impairments in this domain, however in the case of SZ this impairment differs dependently on the hand performing SRTT. We propose that implicit motor sequence learning impairments constitute an overlapping symptom in BD and SZ and suggest further neuroimaging studies to verify cerebellar underpinnings as its cause.

A Study of Biological Rhythm Disturbances in Polish Remitted Bipolar Patients using the BRIAN, CSM, and SWPAQ Scales

BACKGROUND/AIMS

The Biological Rhythms Interview of Assessment in Neuropsychiatry (BRIAN) is a novel tool allowing for a complex assessment of biological rhythms. We compared patients with bipolar disorder (BD) and healthy control subjects (HC) using the Polish version of the BRIAN scale.

METHOD

Fifty-four remitted BD patients (17 males and 37 females aged 52 ± 13 years) and 54 healthy control subjects (25 males and 29 females aged 42 ± 14 years) were studied. In addition to the BRIAN scale, the Composite Scale of Morningness (CSM) and the Sleep-Wake Pattern Assessment Questionnaire (SWPAQ) were employed.

RESULTS

The Polish version of the BRIAN scale displayed high feasibility and consistency, showing that the patients had greater biological rhythm disturbances than the controls. After regression analysis, significant differences were obtained for the BRIAN subscales activity and predominant chronotype, and for the SWPAQ items quality of night-time sleep and ability to stay awake. We obtained positive correlations between higher BRIAN scores and morningness and eveningness, but the correlations with vigilance and the ability to stay awake (on the SWPAQ) were negative.

CONCLUSIONS

Using the BRIAN scale, we confirmed the greater disturbances of biological rhythm in Polish remitted bipolar patients, compared with healthy controls. The differences between these 2 groups in sleep-awake patterns were also demonstrated by the SWPAQ scores. In contrast to other studies, we were unable to confirm an evening chronotype as a discriminating factor between remitted bipolar patients and healthy subjects. This can be explained by the older age and the use of lithium by a significant proportion of the patients.

Executive Functions in Delusion-prone Individuals – Preliminary Studies

Introduction

Executive dysfunctions in psychotic disorders, mainly schizophrenia are well-known phenomenon, however the information about executive functioning in subclinical psychotic states are still scarce. The rationale for focusing on the delusion-proneness (delusion-like states) is suggested role of executive dysfunction in the process of developing delusions.

Aims

Our aim is to assess the relationship between delusion-proneness and executive functions.

Objectives

We would like to assess two cognitive functions: shifting and inhibition and updating, depending on the severity of delusion-like symptoms. We expect that higher delusion-proneness is associated with more pronounced executive dysfunctions, as it is observed in clinical population with existing delusions.

Methods

In order to assess delusion-proneness, we used Polish version of Peters et al. Delusions Inventory (PDI). To evaluate shifting and inhibition, two test were conducted–Berg's Card Sorting Task (BCST) and Stroop task respectively. Correlation analysis were performed.

Results

Sixty-four participants (41 women and 23 men) were recruited in this study. Mean age was 28.8, SD = 10.37. Statistical analysis revealed significant negative correlation of PDI distress subscale and BCST non-perseverative errors. The overall score, as well as all PDI subscales correlated negatively also with the Stroop task's total number of errors and positively with the accuracy in incongruent variant.

Conclusions

Contrary to our expectation, results have shown that delusion-proneness is associated with better results in executive functions test, especially in terms of accuracy. These results suggest that executive functions may play a role in the development and maintenance of delusional ideation, however, its relationship may be a bit more complex.

Disclosure of interest

The authors have not supplied their declaration of competing interest.

The Biological Rhythms Interview of Assessment in Neuropsychiatry in patients with bipolar disorder: correlation with affective temperaments and schizotypy

Objective:

To assess the relationship of biological rhythms, evaluated by the Biological Rhythms Interview of Assessment in Neuropsychiatry (BRIAN), with affective temperaments and schizotypy.

Methods:

The BRIAN assessment, along with the Temperament Evaluation of Memphis, Pisa, Paris, and San Diego-Autoquestionnaire (TEMPS-A) and the Oxford-Liverpool Inventory for Feelings and Experiences (O-LIFE), was administered to 54 patients with remitted bipolar disorder (BD) and 54 healthy control (HC) subjects.

Results:

The TEMPS-A cyclothymic temperament correlated positively and the hyperthymic temperament correlated negatively with BRIAN scores in both the BD and HC groups, although the correlation was stronger in BD subjects. Depressive temperament was associated with BRIAN scores in BD but not in HC; conversely, the irritable temperament was associated with BRIAN scores in HC, but not in BD. Several positive correlations between BRIAN scores and the schizotypal dimensions of the O-LIFE were observed in both BD and HC subjects, especially with cognitive disorganization and less so with unusual experiences and impulsive nonconformity. A correlation with introversion/anhedonia was found only in BD subjects.

Conclusion:

Cyclothymic and depressive temperaments predispose to disturbances of biological rhythms in BD, while a hyperthymic temperament can be protective. Similar predispositions were also found for all schizotypal dimensions, mostly for cognitive disorganization.

[Emotional disorders in patients with cerebellar damage--case studies]

AIM

Growing number of research shows the role of the cerebellum in the regulation of affect. Lesions of the cerebellum can lead to emotional disregulation, a significant part of the Cerebellar Cognitive Affective Syndrome. The aim of this article is to analyze the most recent studies concerning the cerebellar participation in emotional reactions and to present three cases: two female and one male who suffered from cerebellar damage and presented post-traumatic affective and personality change.

METHOD

The patients' neuropsychological examination was performed with Raven's Progressive Matrices Test--standard version, Trial Making Test, Wisconsin Card Sorting Test, Auditory Verbal Learning Test by Luria, Benton Visual Retention Test, Verbal Fluency Test, Stroop Interference Test, Attention and Perceptivity Test (Test Uwagi i Spostrzegawczości TUS), Frontal Behavioral Inventory (FBI).

RESULTS

The review of the literature suggest cerebellar participation, especially teh vermis and paravermial regions, in the detection, integration and filtration of emotional information and in regulation of autonomic emotional responses. In the described patients we observed: oversensitivity, irritability, impulsivity and self-neglect. The man and the woman with right-sided lesions presented similar symptoms: rigidity ofthought, stubbornness, lack of criticism,jocular and inappropriate behavior. The woman with left-sided cerebellar lesion was adynamic, apathic and passive, she presented emotional blunting, social isolation, lack of interests and motivation, general cognitive slowdown.

CONCLUSIONS

Both the analyzed research and the described cases indicate the connection between the cerebellum and emotion regulation. The symptoms presented by the described patients were most probably a consequence of damaged cerebellar projections to subcortical structures (the limbic system) and frontal areas. The diversification of symptoms depending on the localization of lesions had not been described yet and seems to indicate an interesting direction for future research.