Brain imaging in catatonia: systematic review and directions for future research

Catatonia

Catatonia is a neuropsychiatric disorder characterized by motor, affective and cognitive-behavioural signs, which lasts from hours to days. Intensive research over the past two decades has led to catatonia being recognized as an independent diagnosis in the International Classification of Diseases, 11th Revision (ICD-11) since 2022. Catatonia is found in 5-18% of inpatients on psychiatric units and 3.3% of inpatients on medical units. However, in an unknown number of patients, catatonia remains unrecognized and these patients are at risk of life-threatening complications. Hence, recognizing the symptoms of catatonia early is crucial to initiate appropriate treatment to achieve a favourable outcome. Benzodiazepines such as lorazepam and diazepam, electroconvulsive therapy, and N-methyl-D-aspartate antagonists such as amantadine and memantine, are the cornerstones of catatonia therapy. In addition, dopamine-modulating second-generation antipsychotics (for example, clozapine and aripiprazole) are effective in some patient populations. Early and appropriate treatment combined with new screening assessments has the potential to reduce the high morbidity and mortality associated with catatonia in psychiatric and non-psychiatric settings.

Clinical and neuroimaging predictors of benzodiazepine response in catatonia: A machine learning approach

Catatonia is a well characterized psychomotor syndrome combining motor, behavioural and neurovegetative signs. Benzodiazepines are the first-choice treatment, effective in 70 % of cases. Currently, the factors associated with benzodiazepine resistance remain unknown. We aimed to develop machine learning models using clinical and neuroimaging data to predict benzodiazepine response in catatonic patients. This study examined a cohort of catatonic patients who underwent standardized clinical evaluation, 3 T brain MRI, and benzodiazepine trial. Based on clinical response, patients were classified as benzodiazepine responders or non-responders. Cortical thickness and regional brain volumes were measured. Two machine learning models (linear model and gradient boosting tree model) were developed to identify predictors of treatment response using clinical, demographic, and neuroimaging data. The cohort included 65 catatonic patients, comprising 30 benzodiazepine responders and 35 non-responders. Using clinical data alone, the linear model achieved 63% precision, 51% recall, a specificity of 61%, and 58% AUC, while the gradient boosting tree (GBT) model attained 46% precision, 60% recall, a specificity of 62% and 64% AUC. Incorporating neuroimaging data improved model performance, with the linear model achieving 66% precision, 57% recall, a specificity of 67%, and 70% AUC, and the GBT model attaining 50% precision, 50% recall, a specificity of 62% and 70% AUC. The integration of imaging data with demographic and clinical information significantly enhanced the predictive performance of the models. The duration of the catatonic syndrome, along with the presence of mitgehen (passive obedience) and immobility/stupor, and the volume of the right medial orbito-frontal cortex emerged as important factors in predicting non-response to benzodiazepines.

Functional neuroimaging in patients with catatonia: A systematic review

BACKGROUND

Catatonia is a challenging and heterogeneous neuropsychiatric syndrome of motor, affective and behavioral dysregulation which has been associated with multiple disorders such as structural brain lesions, systemic diseases, and psychiatric disorders. This systematic review summarized and compared functional neuroimaging abnormalities in catatonia associated with psychiatric and medical conditions.

METHODS

Using PRISMA methods, we completed a systematic review of 6 databases from inception to February 7th, 2024 of patients with catatonia that had functional neuroimaging performed.

RESULTS

A total of 309 studies were identified through the systematic search and 62 met the criteria for full-text review. A total of 15 studies reported patients with catatonia associated with a psychiatric disorder (n = 241) and one study reported catatonia associated with another medical condition, involving patients with N-methyl-d-aspartate receptor antibody encephalitis (n = 23). Findings varied across disorders, with hyperactivity observed in areas like the prefrontal cortex (PFC), the supplementary motor area (SMA) and the ventral pre-motor cortex in acute catatonia associated to a psychiatric disorder, hypoactivity in PFC, the parietal cortex, and the SMA in catatonia associated to a medical condition, and mixed metabolic activity in the study on catatonia linked to a medical condition.

CONCLUSION

Findings support the theory of dysfunction in cortico-striatal-thalamic, cortico-cerebellar, anterior cingulate-medial orbitofrontal, and lateral orbitofrontal networks in catatonia. However, the majority of the literature focuses on schizophrenia spectrum disorders, leaving the pathophysiologic characteristics of catatonia in other disorders less understood. This review highlights the need for further research to elucidate the pathophysiology of catatonia across various disorders.

A three-dimensional model of neural activity and phenomenal-behavioral patterns

How phenomenal experience and behavior are related to neural activity in physiology and psychopathology represents a fundamental question in neuroscience and psychiatry. The phenomenal-behavior patterns may be deconstructed into basic dimensions, i.e., psychomotricity, affectivity, and thought, which might have distinct neural correlates. This work provides a data overview on the relationship of these phenomenal-behavioral dimensions with brain activity across physiological and pathological conditions (including major depressive disorder, bipolar disorder, schizophrenia, attention-deficit/hyperactivity disorder, anxiety disorders, addictive disorders, Parkinson's disease, Tourette syndrome, Alzheimer's disease, and frontotemporal dementia). Accordingly, we propose a three-dimensional model of neural activity and phenomenal-behavioral patterns. In this model, neural activity is organized into distinct units in accordance with connectivity patterns and related input/output processing, manifesting in the different phenomenal-behavioral dimensions. (1) An external neural unit, which involves the sensorimotor circuit/brain's sensorimotor network and is connected with the external environment, processes external inputs/outputs, manifesting in the psychomotor dimension (processing of exteroception/somatomotor activity). External unit hyperactivity manifests in psychomotor excitation (hyperactivity/hyperkinesia/catatonia), while external unit hypoactivity manifests in psychomotor inhibition (retardation/hypokinesia/catatonia). (2) An internal neural unit, which involves the interoceptive-autonomic circuit/brain's salience network and is connected with the internal/body environment, processes internal inputs/outputs, manifesting in the affective dimension (processing of interoception/autonomic activity). Internal unit hyperactivity manifests in affective excitation (anxiety/dysphoria-euphoria/panic), while internal unit hypoactivity manifests in affective inhibition (anhedonia/apathy/depersonalization). (3) An associative neural unit, which involves the brain's associative areas/default-mode network and is connected with the external/internal units (but not with the environment), processes associative inputs/outputs, manifesting in the thought dimension (processing of ideas). Associative unit hyperactivity manifests in thought excitation (mind-wandering/repetitive thinking/psychosis), while associative unit hypoactivity manifests in thought inhibition (inattention/cognitive deficit/consciousness loss). Finally, these neural units interplay and dynamically combine into various neural states, resulting in the complex phenomenal experience and behavior across physiology and neuropsychiatric disorders.

Historical postmortem studies on catatonia: Close reading and analysis of Kahlbaum's cases and scientific texts between 1800 and 1900

In the 19th century, postmortem brain examination played a central role in the search for the neurobiological origin of psychiatric and neurological disorders. During that time, psychiatrists, neurologists, and neuropathologists examined autopsied brains from catatonic patients and postulated that catatonia is an organic brain disease. In line with this development, human postmortem studies of the 19th century became increasingly important in the conception of catatonia and might be seen as precursors of modern neuroscience. In this report, we closely examined autopsy reports of eleven catatonia patients of Karl Ludwig Kahlbaum. Further, we performed a close reading and analysis of previously (systematically) identified historical German and English texts between 1800 and 1900 for autopsy reports of catatonia patients. Two main findings emerged: (i) Kahlbaum's most important finding in catatonia patients was the opacity of the arachnoid; (ii) historical human postmortem studies of catatonia patients postulated a number of neuroanatomical abnormalities such as cerebral enlargement or atrophy, anemia, inflammation, suppuration, serous effusion, or dropsy as well as alterations of brain blood vessels such as rupture, distension or ossification in the pathogenesis of catatonia. However, the exact localization has often been missing or inaccurate, probably due to the lack of standardized subdivision/nomenclature of the respective brain areas. Nevertheless, Kahlbaum's 11 autopsy reports and the identified neuropathological studies between 1800 and 1900 made important discoveries, which still have the potential to inform and bolster modern neuroscientific research in catatonia.

A systematic scoping review of rodent models of catatonia: Clinical correlations, translation and future approaches

Catatonia is a psychiatric disorder, which subsumes a plethora of affective, motor and behavioral symptoms. In the last two decades, the number of behavioral and neuroimaging studies on catatonia has steadily increased. The majority of behavioral and neuroimaging studies in psychiatric patients suggested aberrant higher-order frontoparietal networks which, on the biochemical level, are insufficiently modulated by gamma-aminobutyric acid (GABA)-ergic and glutamatergic transmission. However, the pathomechanisms of catatonic symptoms have rarely been studied using rodent models. Here, we performed a scoping review of literature available on PubMed for studies on rodent models of catatonia. We sought to identify what we could learn from pre-clinical animal models of catatonia-like symptoms, their underlying neuronal correlates, and the complex molecular (i.e. genes and neurotransmitter) mechanisms by which its modulation exerts its effects. What becomes evident is that although many transgenic models present catatonia-like symptoms, they have not been used to better understand the pathophysiological mechanisms underlying catatonia so far. However, the identified neuronal correlates of catatonia-like symptoms correlate to a great extent with findings from neuroscience research in psychiatric patients. This points us towards fundamental cortical-striatal-thalamocortical and associated networks modulated by white matter inflammation as well as aberrant dopaminergic, GABAergic, and glutamatergic neurotransmission that is involved in catatonia. Therefore, this scoping review opens up the possibility of finally using transgenic models to help with identifying novel target mechanisms for the development of new drugs for the treatment of catatonia.

Structural alterations of amygdala and hypothalamus contribute to catatonia

At present, current diagnostic criteria and systems neglect affective symptom expression in catatonia. This potentially serious omission could explain why putative contributions of limbic system structures, such as amygdala, hippocampus or hypothalamus, to catatonia in schizophrenia spectrum disorders (SSD) have been scarcely investigated so far. To determine whether topographical alterations of the amygdala, hippocampus and hypothalamus contribute to catatonia in SSD patients, we conducted structural magnetic resonance imaging (MRI) of SSD patients with (SSD-Cat, n = 30) and without (SSD-nonCat, n = 28) catatonia as defined by a Northoff Catatonia Rating Scale (NCRS) total score of ≥3 and =0, respectively, in comparison with healthy controls (n = 20). FreeSurfer v7.2 was used for automated segmentation of the amygdala and its 9 nuclei, hippocampus and its 21 subfields and hypothalamus and its associated 5 subunits. SSD-Cat had significantly smaller anterior inferior hypothalamus, cortical nucleus of amygdala, and hippocampal fimbria volumes when compared to SSD-nonCat. SSD-Cat had significantly smaller amygdala, hippocampus and hypothalamus whole and subunit volumes when compared to healthy controls. In SSD-Cat according to DSM-IV-TR (n = 44), we identified positive correlations between Brief Psychiatric Rating Scale (BPRS) item #2 (reflecting anxiety) and respective amygdala nuclei as well as negative correlation between NCRS behavioral score and hippocampus subiculum head. The lower volumes of respective limbic structures involved in affect regulation may point towards central affective pathomechanisms in catatonia.

Brain mechanisms underlying catatonia: A systematic review

BACKGROUND

Catatonia is a complex psychomotor disorder characterized by motor, affective, and behavioral symptoms. Despite being known for almost 150 years, its pathomechanisms are still largely unknown.

METHODS

A systematic research on PubMed, Web of Science, and Scopus was conducted to identify neuroimaging studies conducted on group or single individuals with catatonia. Overall, 33 studies employing structural magnetic resonance imaging (sMRI, n = 11), functional magnetic resonance imaging (fMRI, n = 10), sMRI and fMRI (n = 2), functional near-infrared spectroscopy (fNIRS, n = 1), single positron emission computer tomography (SPECT, n = 4), positron emission tomography (PET, n = 4), and magnetic resonance spectroscopy (MRS, n = 1), and 171 case reports were retrieved.

RESULTS

Observational sMRI studies showed numerous brain changes in catatonia, including diffuse atrophy and signal hyperintensities, while case-control studies reported alterations in fronto-parietal and limbic regions, the thalamus, and the striatum. Task-based and resting-state fMRI studies found abnormalities located primarily in the orbitofrontal, medial prefrontal, motor cortices, cerebellum, and brainstem. Lastly, metabolic and perfusion changes were observed in the basal ganglia, prefrontal, and motor areas. Most of the case-report studies described widespread white matter lesions and frontal, temporal, or basal ganglia hypoperfusion.

CONCLUSIONS

Catatonia is characterized by structural, functional, perfusion, and metabolic cortico-subcortical abnormalities. However, the majority of studies and case reports included in this systematic review are affected by considerable heterogeneity, both in terms of populations and neuroimaging techniques, which calls for a cautious interpretation. Further elucidation, through future neuroimaging research, could have great potential to improve the description of the neural motor and psychomotor mechanisms underlying catatonia.

From operational diagnostic to dimensional-continuum concepts of psychotic and non-psychotic illness: Embracing catatonia across psychopathology and intrinsic movement disorder in neural network dysfunction

Psychiatry is currently negotiating several challenges that are typified by (but are not unique to) schizophrenia: do periodic refinements in operational diagnostic algorithms (a) resolve intricacies and subtleties within and between psychotic and non-psychotic disorders that are authentic and impactful, or (b) constitute arbitrary and porous boundaries that should be complemented, or even replaced, by dimensional-continuum concepts of abnormality and dysfunction. Critically, these issues relate not only to apparent boundaries between diagnoses but also to those between 'health' and 'illness'. This article considers catatonia within evolving dimensional-continuum approaches to the description of impairment and dysfunction among psychotic and non-psychotic disorders. It begins by considering the definition and assessment of catatonia vis-à-vis other disorders, followed by its long-standing conjunction with schizophrenia, relationship with antipsychotic drug treatment, transdiagnostic perspectives and relationships, and pathobiological processes. These appear to involve dysfunction across elements in overlapping neural networks that result in a confluence of psychopathology and intrinsic hypo- and hyperkinetic motor dysfunction. It has been argued that while current diagnostic approaches can have utility in defining groups of cases that are closely related, contemporary evidence indicates categorical diagnoses to be arbitrary divisions of what is essentially a continuous landscape. Psychotic and non-psychotic diagnoses, including catatonia, may reflect arbitrary areas around points of intersection between orthogonal dimensions of psychopathology and intrinsic movement disorder in a poly-dimensional space that characterises this continuous landscape of mental health and dysfunction.

What clinical analysis of antipsychotic-induced catatonia and neuroleptic malignant syndrome tells us about the links between these two syndromes: A systematic review

OBJECTIVES

Antipsychotic-induced catatonia (AIC) and neuroleptic malignant syndrome (NMS) are life-threatening adverse reactions to antipsychotic medication. We conducted a systematic review of literature following the PRISMA statement guidelines to obtain a description of these syndromes (population, context of occurrence, antipsychotic agents implicated) and draw conclusions about their links.

METHODS

We searched Medline and Web of science databases from January 1951 to May 2019 (further restricted from 2000 to 2019) using search terms including "catatonia", "neuroleptic malignant syndrome" and "antipsychotic agents" for case reports, case series and analytic studies. After screening 4082 records, 410 full-text articles (describing 555 events) were assessed for eligibility. We included events of AIC and/or NMS according to Diagnostic and Statistical Manual (DSM) criteria and extracted data about patients' characteristics, context of occurrence, antipsychotic agent(s) involved and treatment outcomes.

RESULTS

We included 165 events (16 AIC, 129 NMS and 20 AIC + NMS) from 144 case reports and case series. The most reported diagnosis was schizophrenia. Comorbid pre-existing conditions such as central nervous system diseases and acute medical events were common. Most of the events (63.3 %) occurred during antipsychotic monotherapy. Second-generation antipsychotics (SGAs, 63.8 %) were overall more implicated than first-generation antipsychotics (FGAs, 36.2 %).

DISCUSSION

Our findings highlight that any antipsychotic medication, even SGA monotherapy prescribed at recommended dose, is at risk for these side effects. FGAs and polypharmacy seem to represent risk factors for malignant catatonia in AIC. The clinical overlap observed between AIC and NMS events in our review suggests a clinical continuum between catatonia and NMS.

Orbitofrontal sulcal patterns in catatonia

BACKGROUND

Catatonia is a psychomotor syndrome frequently observed in disorders with neurodevelopmental impairments, including psychiatric disorders such as schizophrenia. The orbitofrontal cortex (OFC) has been repeatedly associated with catatonia. It presents with an important interindividual morphological variability, with three distinct H-shaped sulcal patterns, types I, II, and III, based on the continuity of the medial and lateral orbital sulci. Types II and III have been identified as neurodevelopmental risk factors for schizophrenia. The sulcal pattern of the OFC has never been investigated in catatonia despite the role of the OFC in the pathophysiology and the neurodevelopmental component of catatonia.

METHODS

In this context, we performed a retrospective analysis of the OFC sulcal pattern in carefully selected homogeneous and matched subgroups of schizophrenia patients with catatonia (N = 58) or without catatonia (N = 65), and healthy controls (N = 82).

RESULTS

Logistic regression analyses revealed a group effect on OFC sulcal pattern in the left (χ2 = 18.1; p < .001) and right (χ2 = 28.3; p < .001) hemispheres. Catatonia patients were found to have more type III and less type I in both hemispheres compared to healthy controls and more type III on the left hemisphere compared to schizophrenia patients without catatonia.

CONCLUSION

Because the sulcal patterns are indirect markers of early brain development, our findings support a neurodevelopmental origin of catatonia and may shed light on the pathophysiology of this syndrome.

Mapping the parent experience of echolalia in autism spectrum disorder onto a conceptual taxonomy

PURPOSE

Echolalia, the repetition of previously heard speech, is prevalent in a variety of neurologic and psychiatric disorders. Within the context of echolalia in autism spectrum disorder (ASD), research and intervention historically assume a clinical standpoint with two opposing paradigms: behaviourism and developmentalism. The literature is largely silent on how those other than researchers and clinicians understand echolalia. This study examined how parents experience echolalia through their children with ASD. The aim of the study was to ascertain if the parental perception of echolalia in ASD aligns with, or offers alternative perspectives to, current clinically-orientated views.

METHOD

We employed online semi-structured interviews to document the experiences of 126 parents, reflecting on their children with ASD aged 3 to 34 years of age, to determine if the parent experience could be mapped onto existing clinical frameworks, or if they might offer new perspectives. We used hermeneutic phenomenological data analysis in an abductive framework.

RESULT

Echolalia has predominantly been represented in literature through the perspectives of behaviourism or developmentalism. We found however, that echolalia is a phenomenon that is experienced by parents in a variety of different ways to that of the current clinically-orientated understandings. Such new ways of understanding echolalia that emerged from our analysis include one understanding which is dependent upon how echolalia is heard, and one in which parents are "waiting for echolalia to evolve."

CONCLUSION

The traditional dichotomous clinical positions do not resonate with all parents, and reliance on these traditional perspectives alone may impact effective engagement with parents and the success of interventions and support strategies. Our findings have implications for future research, the education of clinicians and educators, and the design of support and intervention for those who have echolalia.

Feasibility and usefulness of brain imaging in catatonia

Catatonia is a well characterized psychomotor syndrome that has recognizable motor, affective, behavioural and vegetative manifestations. Despite recent demonstration that catatonia is often associated with brain imaging abnormalities, there is currently no consensus or guidelines about the role of brain imaging. In this study, we assessed the feasibility of brain imaging in a series of patients with catatonia in a routine clinical setting and estimated the prevalence of clinically relevant radiological abnormalities. Sixty patients with catatonia were evaluated against sixty non-healthy controls subjects with headache. The MRI reports were reviewed, and MRI scans were also interpreted by neuroradiologists using a standardised MRI assessment. In this cohort, more than 85% of brain scans of patients with catatonia revealed abnormalities. The most frequently reported abnormalities in the catatonic group were white matter abnormalities (n = 44), followed by brain atrophy (n = 27). There was no evidence for significant differences in the frequency of abnormalities found in radiology reports and standardised neuroradiological assessments. The frequency of abnormalities was similar to that found in a population of non-healthy controls subjects with headache. This study shows that MRI is feasible in patients with catatonia and that brain imaging abnormalities are common findings in these patients. Most frequently, white matter abnormalities and diffuse brain atrophy are observed.

Clinical Neuroimaging Findings in Catatonia: Neuroradiological Reports of MRI Scans of Psychiatric Inpatients With and Without Catatonia

OBJECTIVE

Catatonia is a debilitating psychomotor disorder. Previous neuroimaging studies have used small samples with inconsistent results. The authors aimed to describe the structural neuroradiological abnormalities in clinical magnetic resonance imaging (MRI) brain scans of patients with catatonia, comparing them with scans of psychiatric inpatients without catatonia. They report the largest study of catatonia neuroimaging to date.

METHODS

In this retrospective case-control study, neuroradiological reports of psychiatric inpatients who had undergone MRI brain scans for clinical reasons were examined. Abnormalities were classified by lateralization, localization, and pathology. The primary analysis was prediction of catatonia by presence of an abnormal MRI scan, adjusted for age, sex, Black race-ethnicity, and psychiatric diagnosis.

RESULTS

Scan reports from 79 patients with catatonia and 711 other psychiatric inpatients were obtained. Mean age was 36.4 (SD=17.3) for the cases and 44.5 (SD=19.9) for the comparison group. Radiological abnormalities were reported in 27 of 79 cases (34.2%) and in 338 of 711 in the comparison group (47.5%) (odds ratio [OR]=0.57, 95% confidence interval [CI]=0.35, 0.93; adjusted OR=1.11, 95% CI=0.58, 2.14). Among the cases, most abnormal scans had bilateral abnormalities (N=23, 29.1%) and involved the forebrain (N=25, 31.6%) and atrophy (N=17, 21.5%).

CONCLUSIONS

Patients with catatonia were commonly reported to have brain MRI abnormalities, which largely consisted of diffuse cerebral atrophy rather than focal lesions. No evidence was found that these abnormalities were more common than in other psychiatric inpatients undergoing neuroimaging, after adjustment for demographic variables. Study limitations included a heterogeneous control group and selection bias in requesting scans.

Catatonia associated with epileptic seizures: A systematic review of case reports

The association of catatonia with epileptic seizures is a rare phenomenon that is poorly understood and needs more clinical research. This systematic review included all published case reports of patients with catatonia meeting ICD-11 criteria associated with epileptic seizures, published until December 2021 in PubMed. Case reports were synthesized and results were expressed as percentages. In total, 42 articles with 52 case reports were included. Most patients were adults with a dispersed age (mean age 44.9 ± 19.3), slightly more males (59.6 %), with psychiatric history (76.9 %) of affective disorders (26.9 %) or psychotic episodes (13.5 %) and/or neurological history (61.5 %) of epileptic seizures (38.5 %) or head trauma (13.5 %). Their clinical presentation consisted mostly of decreased psychomotor activity (mutism: 94.2 %; stupor: 78.8 %; staring: 57.7 %; negativism: 36.5 %) with some abnormal psychomotor activity (catalepsy: 40.4 %; rigidity: 40.4 %; waxy flexibility: 23.1 %; posturing: 21.2 %) and half had clinical epileptic seizures (51.9 %), mostly generalized tonic-clonic (23.1 %). Almost all electroencephalograms (97.9 %) and half of brain imaging exams (47.4 %) performed had abnormal findings. The epileptic activity was mainly generalized (50 %) and associated with primary epilepsy (30.8 %), iatrogenesis (23.1 %), other secondary aetiologies (25 %) or unknown causes (21.2 %). Most improved with antiepileptic therapy (87.5 %) and had a complete remission (86.5 %). Catatonia secondary to epileptic seizures often has a nonspecific clinical presentation and appears in patients with previous psychiatric diagnoses, so any patient with catatonia should be properly investigated to avoid misdiagnosis and ineffective treatments.

Molecular and cellular mechanisms leading to catatonia: an integrative approach from clinical and preclinical evidence

This review aims to describe the clinical spectrum of catatonia, in order to carefully assess the involvement of astrocytes, neurons, oligodendrocytes, and microglia, and articulate the available preclinical and clinical evidence to achieve a translational understanding of the cellular and molecular mechanisms behind this disorder. Catatonia is highly common in psychiatric and acutely ill patients, with prevalence ranging from 7.6% to 38%. It is usually present in different psychiatric conditions such as mood and psychotic disorders; it is also a consequence of folate deficiency, autoimmunity, paraneoplastic disorders, and even autistic spectrum disorders. Few therapeutic options are available due to its complexity and poorly understood physiopathology. We briefly revisit the traditional treatments used in catatonia, such as antipsychotics, electroconvulsive therapy, and benzodiazepines, before assessing novel therapeutics which aim to modulate molecular pathways through different mechanisms, including NMDA antagonism and its allosteric modulation, and anti-inflammatory drugs to modulate microglia reaction and mitigate oxidative stress, such as lithium, vitamin B12, and NMDAr positive allosteric modulators.

Resting state functional connectivity and structural abnormalities of the brain in acute retarded catatonia: an exploratory MRI study

In this first cross-sectional MRI study in acute catatonia, we compared the resting state whole-brain, within-network and seed (left precentral gyrus)-to-voxel connectivity, as well as cortical surface complexity between a sample of patients in acute retarded catatonic state (n = 15) diagnosed as per DSM-5 criteria and a demographically matched healthy control sample (n = 15). The patients had comorbid Axis-I psychiatric disorders including schizophrenia spectrum disorders and psychotic mood disorders, but did not have diagnosable neurological disorders. Acute retarded catatonia was characterized by reduced resting state functional connectivity, most robustly within the sensorimotor network; diffuse region of interest (ROI)-ROI hyperconnectivity; and seed-to-voxel hyperconnectivity in the frontoparietal and cerebellar regions. The seed (left precentral gyrus)-to-voxel connectivity was positively correlated to the catatonia motor ratings. The ROI-ROI as well as seed-to-voxel functional hyperconnectivity were noted to be higher in lorazepam responders (n = 9) in comparison to the non-responders (n = 6). The overall Hedges' g effect sizes for these analyses ranged between 0.82 and 3.53, indicating robustness of these results, while the average Dice coefficients from jackknife reliability analyses ranged between 0.6 and 1, indicating fair (inter-regional ROI-ROI connectivity) to perfect (within-sensorimotor network connectivity) reliability of the results. The catatonia sample showed reduced vertex-wise cortical complexity in the right insular cortex and contiguous areas. Thus, we have identified neuroimaging markers of the acute retarded catatonic state that may show an association with treatment response to benzodiazepines. We discuss how these novel findings have important translational implications for understanding the pathophysiology of catatonia as well as for the mechanistic understanding and prediction of treatment response to benzodiazepines.

Application of positron emission tomography in psychiatry-methodological developments and future directions

Mental disorders represent an increasing source of disability and high costs for societies globally. Molecular imaging techniques such as positron emission tomography (PET) represent powerful tools with the potential to advance knowledge regarding disease mechanisms, allowing the development of new treatment approaches. Thus far, most PET research on pathophysiology in psychiatric disorders has focused on the monoaminergic neurotransmission systems, and although a series of discoveries have been made, the results have not led to any material changes in clinical practice. We outline areas of methodological development that can address some of the important obstacles to fruitful progress. First, we point towards new radioligands and targets that can lead to the identification of processes upstream, or parallel to disturbances in monoaminergic systems. Second, we describe the development of new methods of PET data quantification and PET systems that may facilitate research in psychiatric populations. Third, we review the application of multimodal imaging that can link molecular imaging data to other aspects of brain function, thus deepening our understanding of disease processes. Fourth, we highlight the need to develop imaging study protocols to include longitudinal and interventional paradigms, as well as frameworks to assess dimensional symptoms such that the field can move beyond cross-sectional studies within current diagnostic boundaries. Particular effort should be paid to include also the most severely ill patients. Finally, we discuss the importance of harmonizing data collection and promoting data sharing to reach the desired sample sizes needed to fully capture the phenotype of psychiatric conditions.

Clinical Significance of Delirium With Catatonic Signs in Patients With Neurological Disorders

OBJECTIVE

According to DSM-5, catatonia and delirium are mutually exclusive clinical syndromes. The investigators explored the co-occurrence of delirium and catatonia (i.e., catatonic delirium) and the clinical significance of this syndrome with a sample of neurological patients.

METHODS

This prospective study with consecutive sampling included patients diagnosed with delirium at the National Institute of Neurology and Neurosurgery of Mexico. DSM-5 criteria for delirium, the Confusion Assessment Method, and the Delirium Rating Scale-Revised-98 were used to select and characterize patients. Catatonia was assessed using the Bush-Francis Catatonia Rating Scale and DSM-5 diagnostic criteria. Logistic regression analysis was performed to identify etiological factors associated with catatonic delirium.

RESULTS

A total of 264 patients with delirium were included, 61 (23%) of whom fulfilled the criteria for catatonia and delirium simultaneously. Brain tumors, subarachnoid hemorrhage, acute hydrocephalus, and ischemic stroke were associated with delirium without catatonic signs. Catatonic delirium was observed among patients with encephalitis, epilepsy, brain neoplasms, and brain tuberculosis. After multivariate analysis, the association between catatonic delirium and encephalitis (both viral and anti-N-methyl-d-aspartate receptor [NMDAR]) was confirmed.

CONCLUSIONS

Delirium is a common complication of neurological diseases, and it can coexist with catatonia. The recognition of catatonic delirium has clinical significance in terms of etiology, as it was significantly associated with viral and anti-NMDAR encephalitis.

Catatonia in older adults: A systematic review

BACKGROUND

Catatonia is a complex psychomotor syndrome that often goes unrecognized and untreated, even though its classification has evolved in recent years. Prompt and correct identification of catatonia allows for highly effective treatment and prevention of possible complications. The underrecognition of catatonia in older patients is also frequent, and research in this population is scarce.

AIM

To conduct a systematic review of the literature on catatonia in older people to ascertain its clinical characteristics across settings.

METHODS

Following the PRISMA guidelines, MEDLINE, EMBASE, and PsycINFO databases were searched from inception to December 2021, with a strategy aimed at identifying all articles published on catatonia in older adults. Titles and abstracts were scanned and selected independently by two authors. Papers investigating issues related to catatonia and/or catatonic symptoms in older people, with English abstracts available, were included. References of selected articles were revised to identify other relevant studies.

RESULTS

In total, 1355 articles were retrieved. After removing duplicates, 879 remained. Of the 879 identified abstracts, 669 were excluded because they did not meet the inclusion criteria. A total of 210 articles underwent full text review, and 51 were eliminated for various reasons. Fourteen more articles were selected from the references. Overall, 173 articles were reviewed: 108 case reports, 35 case series, 11 prospective cohort studies, 6 case-control studies, 3 retrospective cohort studies and 10 reviews. We found several particular aspects of catatonia in this population. Catatonia in older patients is highly prevalent and tends to have a multifactorial etiology. Older patients, compared to younger patients, have a higher risk of developing catatonia with benzodiazepine (BZD) withdrawal, in bipolar disorder, and in the general hospital. Age, together with other risk factors, was significantly associated with the incidence of deep venous thrombosis, neuroleptic malignant syndrome poor outcome, other complications and mortality. Treatment with BZDs and electroconvulsive therapy is safe and effective. Prompt treatment of its cause is essential to ensure a good prognosis.

CONCLUSION

Catatonia in older patients is highly prevalent and tends to have a multifactorial etiology. The risk of developing catatonia in some settings and conditions, as well as of developing complications, is high in this population. Symptomatic treatment is safe and effective, and timely etiologic treatment is fundamental.

Echolalia from a transdiagnostic perspective

BACKGROUND & AIMS

Echolalia, the repetition of one's or others' utterances, is a behavior present in typical development, autism spectrum disorder, aphasias, Tourette's, and other clinical groups. Despite the broad range of conditions in which echolalia can occur, it is considered primarily through a disorder-specific lens, which limits a full understanding of the behavior.

METHOD

Empirical and review papers on echolalia across disciplines and etiologies were considered for this narrative review. Literatures were condensed into three primary sections, including echolalia presentations, neural mechanisms, and treatment approaches.

MAIN CONTRIBUTION

Echolalia, commonly observed in autism and other developmental conditions, is assessed, observed, and treated in a siloed fashion, which reduces our collective knowledge of this communication difference. Echolalia should be considered as a developmental, transdiagnostic, and communicative phenomenon. Echolalia is commonly considered as a communicative behavior, but little is known about its neural etiologies or efficacious treatments.

CONCLUSIONS

This review is the first to synthesize echolalia from a transdiagnostic perspective, which allows for the direct comparisons across and within clinical groups to inform assessment, treatment, conceptualization, and research recommendations.

IMPLICATIONS

Considering echolalia transdiagnostically highlights the lack of consensus on operationalization and measurement across and within disorders. Clinical and research future directions need to prioritize consistent definitions of echolalia, which can be used to derive accurate prevalence estimates. Echolalia should be considered as a communication strategy, used similarly across developmental and clinical groups, with recommended strategies of shaping to increase its effectiveness.

Efficacy of Transcranial Direct-Current Stimulation in Catatonia: A Review and Case Series

Catatonia is a severe neuropsychiatric syndrome, usually treated by benzodiazepines and electroconvulsive therapy. However, therapeutic alternatives are limited, which is particularly critical in situations of treatment resistance or when electroconvulsive therapy is not available. Transcranial direct-current stimulation (tDCS) is a promising non-invasive neuromodulatory technique that has shown efficacy in other psychiatric conditions. We present the largest case series of tDCS use in catatonia, consisting of eight patients in whom tDCS targeting the left dorsolateral prefrontal cortex and temporoparietal junction was employed. We used a General Linear Mixed Model to isolate the effect of tDCS from other confounding factors such as time (spontaneous evolution) or co-prescriptions. The results indicate that tDCS, in addition to symptomatic pharmacotherapies such as lorazepam, seems to effectively reduce catatonic symptoms. These results corroborate a synthesis of five previous case reports of catatonia treated by tDCS in the literature. However, the specific efficacy of tDCS in catatonia remains to be demonstrated in a randomized controlled trial. The development of therapeutic alternatives in catatonia is of paramount importance.

Progress in sensorimotor neuroscience of schizophrenia spectrum disorders: Lessons learned and future directions

The number of neuroimaging studies on movement disorders, sensorimotor, and psychomotor functioning in schizophrenia spectrum disorders (SSD) has steadily increased over the last two decades. Accelerated by the addition of the "sensorimotor domain" to the Research Domain Criteria (RDoC) framework in January 2019, neuroscience research on the role of sensorimotor dysfunction in SSD has gained greater scientific and clinical relevance. To draw attention to recent rapid progress in the field, we performed a triennial systematic review (PubMed search from January 1st^, 2018 through December 31st^, 2020), in which we highlight recent neuroimaging findings and discuss methodological pitfalls as well as challenges for future research. The identified magnetic resonance imaging (MRI) studies suggest that sensorimotor abnormalities in SSD are related to cerebello-thalamo-cortico-cerebellar network dysfunction. Longitudinal and interventional studies highlight the translational potential of the sensorimotor domain as putative biomarkers for treatment response and as targets for non-invasive neurostimulation techniques in SSD.

Clinical features and predictors of non-response in severe catatonic patients treated with electroconvulsive therapy

OBJECTIVE

To explore the demographic and clinical features of severe catatonic patients, comparing responders and non-responders to ECT in order to detect possible predictors of non-response.

METHODS

This naturalistic study included 59 catatonic inpatients with a diagnosis of mood disorder according to DSM-IV-TR criteria. All patients were treated with bilateral ECT and evaluated before and after ECT course. The response to ECT was defined as a Clinical Global Impression (Improvement subscale) rating 1 'very much improved' or 2 'much improved'. Clinical variables were compared between responders and non-responders; logistic regression was used to predict the probability of non-response, with regard to the symptoms presented by the patients.

RESULTS

The response rate was 83.1%. Non-responders (n = 10) to ECT showed neurological comorbidities, treatments with dopamine agonists and anticholinergic drugs, waxy flexibility, and echophenomena more frequently than respondents (n = 49). Echophenomena resulted a significant predictor of non-response in the multivariate analysis.

CONCLUSION

In line with previous reports, ECT resulted effective in the vast majority of severe catatonic patients. The association between ECT resistant catatonia and neurological comorbidity, use of dopamine-agonist and anticholinergic medications is consistent with the hypothesis that ECT is more effective in 'top-down' than in 'bottom-up' variant of catatonia.Key pointsCatatonic symptoms are frequently associated with severe and psychotic mood disorders.Electroconvulsive therapy is effective in treating most forms of severe catatonia.Neurological comorbidity and the presence of 'echopraxia/echolalia' could represent predictors of non-response to ECT.

[The sensorimotor domain in the research domain criteria system: progress and perspectives]

Over the past three decades research interest in hypokinetic, hyperkinetic, sensorimotor and psychomotor abnormalities in mental disorders has steadily increased. This development has led to an increasing number of scientific initiatives that have not only highlighted the clinical need for early detection of extrapyramidal motor symptoms, tardive dyskinesia and catatonia but also provided numerous neurobiological findings and clinically relevant results based on the pathology of the sensorimotor system in patients with mental disorders. In view of these developments in January 2019 the National Institute of Mental Health (NIMH) research domain criteria (RDoC) initiative introduced a sixth domain called the sensorimotor domain to address deficits in the sensorimotor system and associated behavioral abnormalities. To draw attention to the rapid progress just since the introduction of the sensorimotor domain, a 2-year (1 January 2019-18 February 2021) systematic review is presented highlighting recent neuroimaging findings and discussing challenges for future research. In summary, aberrant sensorimotor processing in mental disorders is associated with dysfunction of the cerebello-thalamo-motor cortex network, which interacts with (social)cognitive and affective systems. Initial longitudinal and interventional studies highlight the translational potential of the sensorimotor domain.

Brainstem alterations contribute to catatonia in schizophrenia spectrum disorders

Catatonia is a severe psychomotor syndrome that frequently occurs in patients with schizophrenia spectrum disorders (SSD). Accumulating neuroimaging evidence suggests orbitofrontal, frontoparietal and cerebellar network dysfunction in catatonia. Very little is known about contributions of brainstem regions (as part of the dopaminergic-based subcortical-cortical motor circuit) to catatonia in SSD patients. Here, we used structural magnetic resonance imaging (MRI) at 3 T to examine volumes of brainstem regions in catatonic SSD patients compared to non-catatonic SSD patients. Catatonia severity was measured with the Northoff Catatonia Rating Scale (NCRS). The segmentation of the brainstem in order to investigate the volumes of medulla oblongata, pons, superior cerebellar pedunculus, and midbrain was carried out using FreeSurfer vers. 6.0. Catatonic patients (NCRS total score ≥ 3; at least 1 point in the three different symptom categories; i.e., motor, behavioral, and affective; n = 30) had significantly smaller midbrain volumes (p = 0.004, Bonferroni corr.) when compared to non-catatonic patients (NCRS total score = 0; n = 29). In catatonic patients, significant correlations were detected between NCRS motor scores and whole brainstem (p = 0.015, Bonferroni corr.) volumes. These results support a neuromechanistically important role of brainstem structures in catatonia in SSD, particularly in motor symptom expression.