Stereotypies: A critical appraisal and suggestion of a clinically useful definition

[Formula: see text] Caregiver-reported infant motor and imitation skills predict M-CHAT-R/F

Altered motor and social-communicative abilities in infancy have been linked to later ASD diagnosis. Most diagnostic instruments for ASD cannot be utilized until 12 months, and the average child is diagnosed substantially later. Imitation combines motor and social-communicative skills and is commonly atypical in infants at risk for ASD. However, few measures have been developed to assess infant imitation clinically. One barrier to the diagnostic age gap of ASD is accessibility of screening and diagnostic services. Utilization of caregiver report to reliably screen for ASD mitigates such barriers and could aid in earlier detection. The present study developed and validated a caregiver-report measure of infant imitation at 4, 6, and 9 months and explored the relationship between caregiver-reported imitation and motor abilities with later ASD risk. Participants (N = 571) were caregivers of term and preterm infants recruited as part of a large multi-site study of PediaTrac™, a web-based tool for monitoring and tracking infant development. Caregivers completed online surveys and established questionnaires on a schedule corresponding to well-child visits from birth to 18 months, including the M-CHAT-R/F at 18 months. Distinct imitation factors were derived from PediaTrac at 4, 6, and 9 months via factor analysis. The results supported validity of the imitation factors via associations with measures of infant communication (CSBS; ASQ). Imitation and motor skills at 9 months predicted 18-month ASD risk over and above gestational age. Implications for assessment of infant imitation, detecting ASD risk in the first year, and contributing to access to care are discussed.

Mannerisms and stereotypies in catatonia: beyond simple motor movements

Background

Catatonia is a complex syndrome with prominent psychomotor, cognitive, and affective manifestations. Among the commonly described manifestations of catatonia are mannerisms and stereotypies. Kahlbaum, who coined the term catatonia, described several presentations of mannerisms and stereotypies as complex behaviors in his monograph. However, most of the subsequent psychiatric literature has described both phenomena in the context of simple motor movements or actions.

Study design or method

We identified complex behavioral presentations of mannerisms and stereotypies described by Kahlbaum in his monograph. We summarize the development and use of mannerisms and stereotypies as psychiatric terminology since Kahlbaum, emphasizing the spectrum of behavior captured early in this usage. We list the inconsistent and interchangeable use of these terms in subsequent literature and describe recent examples of complex behavioral manifestations of mannerisms and stereotypies in the context of catatonia.

Study results

We propose a new framework for mannerisms and stereotypies that utilizes descriptive psychopathology factors in various normative references, the context of the behavior examined, and critical pathological processes identified in mannerisms and stereotypies to identify and describe complex manifestations of these phenomena.

Conclusion

Catatonia continues to remain under-recognized and under-treated. Our current diagnostic tools can make mannerisms and stereotypies complex and challenging to recognize. We suggest defining stereotypies as non-contextual repetitive activities while mannerisms as non-contextual peculiarities of activities. Utilizing our proposed framework and definitions can improve the description, recognition, and treatment of catatonia.

Defining repetitive behaviours in frontotemporal dementia

Repetitive behaviours are common manifestations of frontotemporal dementia (FTD). Patients with FTD exhibit various types of repetitive behaviours with unique behavioural and cognitive substrates, including compulsivity, lack of impulse control, stereotypy and hoarding. Other sources of repetitive behaviours, such as restrictive interests and insistence on sameness, may also be seen in FTD. Although repetitive behaviours are highly prevalent and potentially discriminatory in this population, their expression varies widely between patients, and the field lacks consensus about the classification of these behaviours. Terms used to describe repetitive behaviours in FTD are highly heterogeneous and may lack precise definitions. This lack of harmonization of the definitions for distinct forms of repetitive behaviour limits the ability to differentiate between pathological behaviours and impedes understanding of their underlying mechanisms. This review examines established definitions of well-characterized repetitive behaviours in other neuropsychiatric disorders and proposes operational definitions applicable to patients with FTD. Building on extant models of repetitive behaviours in non-human and lesion work and models of social behavioural changes in FTD, we describe the potential neurocognitive bases for the emergence of different types of repetitive behaviours in FTD and their potential perpetuation by a predisposition towards habit formation. Finally, examples of distinct therapeutic approaches for different forms of repetitive behaviours are highlighted, along with future directions to accurately classify, measure and treat these symptoms when they impair quality of life.

Co-morbid tics and stereotypies: a systematic literature review

BACKGROUND

Tics and stereotypies are childhood-onset repetitive behaviours that can pose significant diagnostic challenges in clinical practice. Both tics and stereotypies are characterised by a complex co-morbidity profile, however little is known about the co-occurrence of these hyperkinetic disorders in the same patient population.

OBJECTIVE

This review aimed to assess the relationship between tics and stereotypies when these conditions present in co-morbidity.

METHODS

We conducted a systematic literature review of original studies on co-morbid tics and stereotypies, according to the standards outlined in the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines.

RESULTS

Our literature search identified six studies of suitable sample size (n ≥ 40) presenting data on the association between tics and stereotypies in otherwise typically developing patients. A considerable proportion (23%) of patients diagnosed with stereotypic movement disorder present with co-morbid tics (range 18-43%). Likewise, the prevalence of primary stereotypies is increased in patients with tic disorders such as Tourette syndrome (8%, range 6-12%).

DISCUSSION

Tics and stereotypies can often develop in co-morbidity. The association of tics and stereotypies in the same patient has practical implications, in consideration of the different treatment approaches. Future research should focus on the assessment and management of both conditions, particularly in special populations (e.g. patients with pervasive developmental disorders).

Tardive Dyskinesia With Chorea-Ballism Improved by Valbenazine: A Case Report

Tardive dyskinesia (TD) is an involuntary muscle movement typically caused by prolonged exposure to antipsychotic medications. Depending on the symptom severity and the affected body parts, it can cause a terrible decline in patients' daily activities and life quality. TD often persists despite discontinuation of the offending drugs. There was no approved or effective agent to treat the patients until valbenazine, a vesicular monoamine transporter-2 inhibitor, became available. We report the case of a 64-year-old woman who started to take antipsychotics at the age of her late 20s for her schizophrenic symptoms and later developed left arm chorea-ballism in mid-50s. The patient's involuntary movements got progressively worse even after being freed from the medications and caused severe body weight loss due to difficulties in taking meals. Daily treatment with valbenazine gradually mitigated her symptoms, resulting in significant improvement in her feeding activities, body weight, and daily life quality. This is the first report, to our knowledge, describing the therapeutic potential of valbenazine to improve chorea-ballism associated with TD. Our observation highlights that valbenazine may relieve a broader spectrum of antipsychotic-induced involuntary movements.

The Collateral Effects of Antecedent Exercise on Stereotypy and Other Nonstereotypic Behaviors Exhibited by Individuals with Autism Spectrum Disorder: A Systematic Review

The presence of stereotypy is one of the core features exhibited by individuals diagnosed with autism spectrum disorder (ASD). Stereotypy can interfere with academic engagement and become a major barrier to appropriate education and social development of individuals with ASD. Studies have shown that antecedent physical exercise can produce reductions in stereotypy and positive collateral effects. The purpose of the current systematic review was to examine the collateral effects of antecedent physical exercise on stereotypy and engagement in nonstereotypic behaviors. The findings suggest that individuals with ASD can benefit from incorporating antecedent physical exercise with regard to stereotypy and other positive collateral behaviors. Implications of the results and areas for further research are discussed.

"Unvoluntary" Movement Disorders: Distinguishing between Tics, Akathisia, Restless Legs, and Stereotypies

Tics, stereotypies, akathisia, and restless legs fall at different places on the spectrum of discrete, unwanted and potentially disabling motor routines. Unlike tremor, chorea, myoclonus, or dystonia, this subgroup of abnormal movements is characterized by the subject's variable ability to inhibit or release undesired motor patterns on demand. Though it may be sometimes clinically challenging, it is crucial to distinguish these "unvoluntary" motor behaviors because secondary causes and management approaches differ substantially. To this end, physicians must consider the degree of repetitiveness of the movements, the existence of volitional control, and the association with sensory symptoms, or cognitive-ideational antecedent. This review aims to summarize the current existing knowledge on phenomenology, diagnosis, and treatment of tics, stereotypies, akathisia, and restless leg syndrome.

Motor stereotypies in autism spectrum disorder: Clinical randomized study and classification proposal

LAY ABSTRACT

Motor stereotypies are one of the most frequent features in children with a diagnosis of autism spectrum disorder. They may disrupt children's functioning and development and be a potential source of stress for families. Several factors, including sex, age, cognitive ability, and severity of autism spectrum disorder, may influence the presence and intensity of stereotypies. The present study aimed to identify the prevalence of motor stereotypies in a group of children with autism spectrum disorder. In addition, it sought to investigate whether sex, age, cognitive ability, verbal language, neurological comorbidities, and severity of autism spectrum disorder were associated with an increased probability and higher number, duration, and variability of stereotypies. A total of 134 participants aged 2.3-17.6 years underwent a clinical protocol with standardized video-recorded sessions. Stereotypies were identified and classified by two independent evaluators. The prevalence of stereotypies was 56.7%, and a total of 1198 motor stereotypies were captured. Children who were younger, nonverbal, and had higher severity of autism spectrum disorder had an increased probability of presenting stereotypies. Being nonverbal or having higher severity of autism spectrum disorder was also associated with presenting a higher number of stereotypies. Children with developmental delay, intellectual disability, or epilepsy displayed longer stereotypies, and children with developmental delay or intellectual disability additionally presented more diverse stereotypies. As part of the study, the authors present a clinical classification model, a glossary, and video samples of motor stereotypies. The findings of this study suggest that children who are younger, nonverbal, have lower cognitive ability, and have higher severity of autism spectrum disorder may have a higher burden of stereotypies. Earlier intervention and monitoring of these children have the potential to improve their long-term outcomes.

Clinical management of complex motor stereotypies

This paper will review complex motor stereotypies and provide a summary of the current proposed treatment pathway.

Tics and Tourette Syndrome: A Literature Review of Etiological, Clinical, and Pathophysiological Aspects

Tourette syndrome (TS) is a condition characterized by tics produced because of neuropsychiatric malfunctioning occurring in childhood, which becomes less severe in adulthood, followed by a difference in the severity of tics between two persons. TS is a diverse variable in which symptoms vary in different patients. It is associated with comorbidities like obsessive-compulsive disorder (OCD), attention deficit hyperactivity disorder (ADHD), and depression, and hampers the quality of life. Comorbid disorders must be investigated and treated as part of the clinical approach for all TS patients. Clinicians should be aware of the infrequent but serious neurological problems that can occur in these patients and recommend aggressively treating tics. Currently, there is more emphasis on symptom-based treatments by medicines, but as etiological knowledge improves, we will divert to disease-modifying medications in the future. Behavioral, pharmacological, and surgical methods can treat TS. Neuroleptics, other drugs, and behavioral therapies are the first-line options. Deep brain stimulation is evolving but has its pros and cons. The main focus of this review is on tics characteristics, how to manage and assess them, and limitations in the clinical spectrum.

We Move or Are We Moved? Unpicking the Origins of Voluntary Movements to Better Understand Semivoluntary Movements

The capacity for voluntary control is seen as essential to human movements; the sense that one intended to move (willing) and those actions were self-generated (self-agency) gives the sense of voluntariness and of being in control. While the mechanisms underlying voluntary movement have long been unclear, recent neuroscientific tools have identified networks of different brain areas, namely, the prefrontal cortex, supplementary motor area, and parietal cortex, that underlie voluntary action. Dysfunction in these brain areas can result in different forms of semivoluntary movement as the borderland of voluntary and involuntary movement where a person may experience a disordered sense of will or agency, and thus the movement is experienced as unexpected and involuntary, for an otherwise voluntary-appearing movement. Tics, functional movement disorders, stereotypies, perseveration, compulsions, utilization behaviors, and motor mannerism have been described elsewhere in the context of psychoses, and are often mistaken for each other. Yet, they reflect an impairment of prefrontal cortices and related circuits rather than simple motor systems, which results in the absence of subjective recognition of the movements, in contrast to other neurological movement disorders where principal abnormalities are located within the basal ganglia and its connections. Therefore, their recognition is clinically important since they are usually associated with neurodevelopmental and neurodegenerative disorders. In this review, we first defined a conceptual framework, from both a neuroanatomical and a neurophysiological point of view, for the generation of voluntary movement. We then examined the evidence linking dysfunctions in different motor pathways to each type of movement disorder. We looked at common semivoluntary movement disorders providing an overview, where possible, of their phenomenology and brain network abnormalities for each condition. We also emphasized important clinical feature similarities and differences to increase recognition of each condition in practice.

Frontal lobe seizures: overview and update

Frontal lobe seizures (FLS) are debilitating for patients, highly diverse and often challenging for clinicians to evaluate. Frontal lobe epilepsy is the second most common localization for focal epilepsy, and if pharmacoresistant, can be amenable to resective surgery. Detailed study of frontal seizure semiology in conjunction with careful anatomical and electrophysiological correlation based on intracerebral recording with stereoelectroencephalography (SEEG) has allowed demonstration that ictal motor semiology reflects a hierarchical rostro-caudal axis of frontal lobe functional organization, thus helping with presurgical localization. Main semiological features allowing distinction between different frontal sublobar regions include motor signs and emotional signs. Frontal lobe seizure semiology also represents a valuable source of in vivo human behavioral data from a neuroscientific perspective. Advances in defining underlying etiologies of FLE are likely to be crucial for appropriate selection and exploration of potential surgical candidates, which could improve upon current surgical outcomes. Future research on investigating the genetic basis of epilepsies and relation to structural substrate (e.g. focal cortical dysplasia) and seizure organization and expression, could permit a "genotype-phenotype" approach that could be complementary to anatomical electroclinical correlations in better defining the spectrum of FLS. This could help with optimizing patient selection and prognostication with regards to therapeutic choices.

Dopamine transporter silencing in the rat: systems-level alterations in striato-cerebellar and prefrontal-midbrain circuits

Silencing of dopamine transporter (DAT), a main controlling factor of dopaminergic signaling, results in biochemical and behavioral features characteristic for neuropsychiatric diseases with presumed hyperdopaminergia including schizophrenia, attention deficit hyperactivity disorder (ADHD), bipolar disorder, and obsessive-compulsive disorder (OCD). Investigation of DAT silencing thus provides a transdiagnostic approach towards a systems-level understanding of common underlying pathways. Using a high-field multimodal imaging approach and a highly sensitive cryogenic coil, we integrated structural, functional and metabolic investigations in tandem with behavioral assessments on a newly developed preclinical rat model, comparing DAT homozygous knockout (DAT-KO, N = 14), heterozygous knockout (N = 8) and wild-type male rats (N = 14). We identified spatially distributed structural and functional brain alterations encompassing motor, limbic and associative loops that demonstrated strong behavioral relevance and were highly consistent across imaging modalities. DAT-KO rats manifested pronounced volume loss in the dorsal striatum, negatively correlating with cerebellar volume increase. These alterations were associated with hyperlocomotion, repetitive behavior and loss of efficient functional small-world organization. Further, prefrontal and midbrain regions manifested opposite changes in functional connectivity and local network topology. These prefrontal disturbances were corroborated by elevated myo-inositol levels and increased volume. To conclude, our imaging genetics approach provides multimodal evidence for prefrontal-midbrain decoupling and striato-cerebellar neuroplastic compensation as two key features of constitutive DAT blockade, proposing them as transdiagnostic mechanisms of hyperdopaminergia. Thus, our study connects developmental DAT blockade to systems-level brain changes, underlying impaired action inhibition control and resulting in motor hyperactivity and compulsive-like features relevant for ADHD, schizophrenia and OCD.

Not the Stereotypical Wilson Disease: A Case Report

Background:

Wilson disease (WD), a potentially treatable genetic disorder with perturbations in copper metabolism, presents with hepatic and neuropsychiatric manifestations. Both hyper and hypokinetic movements predominate the latter spectrum. Motor stereotypies, however, are exceedingly rare.

Case Report:

We present a case of a 12-year-old girl, with progressive behavioural alterations and cognitive impairment, with motor stereotypies involving the upper limbs, as the dominant movement semiology. She was diagnosed as WD with evidence of striatal involvement on brain imaging. Her motor symptoms partially responded to chelation therapy.

Discussion:

There are about five documented cases of motor stereotypies in WD worldwide, with only one being previously reported from India.

Putative neural consequences of captivity for elephants and cetaceans

The present review assesses the potential neural impact of impoverished, captive environments on large-brained mammals, with a focus on elephants and cetaceans. These species share several characteristics, including being large, wide-ranging, long-lived, cognitively sophisticated, highly social, and large-brained mammals. Although the impact of the captive environment on physical and behavioral health has been well-documented, relatively little attention has been paid to the brain itself. Here, we explore the potential neural consequences of living in captive environments, with a focus on three levels: (1) The effects of environmental impoverishment/enrichment on the brain, emphasizing the negative neural consequences of the captive/impoverished environment; (2) the neural consequences of stress on the brain, with an emphasis on corticolimbic structures; and (3) the neural underpinnings of stereotypies, often observed in captive animals, underscoring dysregulation of the basal ganglia and associated circuitry. To this end, we provide a substantive hypothesis about the negative impact of captivity on the brains of large mammals (e.g., cetaceans and elephants) and how these neural consequences are related to documented evidence for compromised physical and psychological well-being.

Early-onset eyelid stereotypies are a frequent and distinctive feature in Dravet syndrome

Dravet syndrome (DS) is a severe infantile-onset epilepsy syndrome featuring drug resistant epilepsy, global developmental delay and intellectual disability. In addition to ataxia and progressive crouch gait, Parkinsonism has recently been reported as characteristic in young adults with DS. We describe 5 patients out of a series of 23 patients with DS who present between 12 and 24 months of age with repetitive episodes of eyelid closure, sometimes as fast as eye blinking or flickering. Consistent lack of any EEG correlate in serial video-EEG ruled out an epileptic origin. We propose that this movement disorder, namely 'eyelid stereotypies', might be an early motor trait of SCN1A-associated DS.

Rethinking Stereotypies in Autism

Stereotyped movements ("stereotypies") are semi-voluntary repetitive movements that are a prominent clinical feature of autism spectrum disorder. They are described in first-person accounts by people with autism as relaxing and that they help focus the mind and cope in overwhelming sensory environments. Therefore, we generally recommend against techniques that aim to suppress stereotypies in individuals with autism. Further, we hypothesize that understanding the neurobiology of stereotypies could guide development of treatments to produce the benefits of stereotypies without the need to generate repetitive motor movements. Here, we link first-person reports and clinical findings with basic neuroanatomy and physiology to produce a testable model of stereotypies. We hypothesize that stereotypies improve sensory processing and attention by regulating brain rhythms, either directly from the rhythmic motor command, or via rhythmic sensory feedback generated by the movements.

Phonic and Motor Stereotypies in Autism Spectrum Disorder: Video Analysis and Neurological Characterization

Stereotypies are among the core symptoms of Autism spectrum disorder (ASD) and can cause significant clinical impairment. At present, phonic stereotypies in ASD have been scarcely explored. This study investigates the frequency, variability, and typologies of phonic and motor stereotypies in children with ASD and their association with clinical neurological variables. We examined 35 patients by recording standardized video sessions and administering the Autism Diagnostic Observation Schedule-Second Edition (ADOS-2). Phonic stereotypies were present in 83.0% of the patients. The most prevalent subtypes were noncommunicative vocalizations (60.0%), single syllables (37.1%), and echolalic stereotypies (22.9%). Noncommunicative vocalizations were more frequent in nonverbal patients (OR = 4.629, p = 0.008), while echolalic stereotypies were more represented in verbal patients (OR = 0.279, p = 0.028). Patients with intellectual disability (ID) showed a higher number (F(1,26) = 9.406, p = 0.005) and variability (F(1,25) = 7.174, p = 0.013) of motor stereotypies, with a higher number (F(1,26) = 13.268, p = 0.005) and variability (F(1,26) = 9.490, p = 0.005) of stereotypies involving the head/trunk/shoulders category. Patients with guttural stereotypies showed a higher variability of total motor stereotypies (OR = 1.487, p = 0.032) and self-directed motor stereotypies (OR = 4.389, p = 0.042). These results, combined with a standardized video-analysis, document the frequency and variability of phonic stereotypies among children with ASD. Correlations between specific phonic stereotypies and verbal abilities should be investigated further.

Diagnostic approach to paediatric movement disorders: a clinical practice guide

Paediatric movement disorders (PMDs) comprise a large group of disorders (tics, myoclonus, tremor, dystonia, chorea, Parkinsonism, ataxia), often with mixed phenotypes. Determination of the underlying aetiology can be difficult given the broad differential diagnosis and the complexity of the genotype-phenotype relationships. This can make the diagnostic process time-consuming and difficult. In this overview, we present a diagnostic approach for PMDs, with emphasis on genetic causes. This approach can serve as a framework to lead the clinician through the diagnostic process in eight consecutive steps, including recognition of the different movement disorders, identification of a clinical syndrome, consideration of acquired causes, genetic testing including next-generation sequencing, post-sequencing phenotyping, and interpretation of test results. The aim of this approach is to increase the recognition and diagnostic yield in PMDs. WHAT THIS PAPER ADDS: An up-to-date description and diagnostic framework for testing of paediatric movement disorders is presented. The framework helps to determine which patients will benefit from next-generation sequencing.

Transitional Care for Young People with Neurological Disorders: A Scoping Review with A Focus on Patients with Movement Disorders

Childhood-onset movement disorders represent a heterogenous group of conditions. Given the complexity of these disorders, the transition of care from pediatric to adult medicine is an important consideration. We performed a scoping review of the literature on transitional care in chronic neurological disease, exploring key transitional issues and proposed transitional care models. Our aim was to describe the current knowledge and gaps about the transition process of young adults with chronic neurological disorders, paying special attention to childhood onset movement disorders. A total of 64 articles were included in the qualitative synthesis; 56 articles reported on transitional care issues, and 8 articles reported on transitional care models. Only 2 articles included patients with movement disorders. The following 4 main transitional issues were identified following synthesis of the available literature: (1) inadequate preparation for the transition process, (2) inappropriate and inconsistent transition practices, (3) inadequate adult services, and (4) heightened emotional response surrounding transition. Of the reported transitional care models, multidisciplinary ambulatory care was the most common approach. In studies evaluating patient-related outcomes, positive health, educational, and vocational outcomes were found. The available literature provides insights on issues that can arise during transition that should be addressed to improve patient and caregiver comfort and satisfaction with care. Further research is needed to evaluate how transitional care programs affect outcomes and their cost effectiveness. More studies are required to determine the needs and outcomes specific to patients with childhood onset movement disorders. © 2020 International Parkinson and Movement Disorder Society.

The Spectrum of Repetitive Behaviors Associated With Subacute Sclerosing Panencephalitis

BACKGROUND

Repetitive behaviors refer to a broad class of responses ranging from stereotypic body movements to impulsive/compulsive behaviors. They may be associated with neurological disorders.

METHODS

This is a case series of six subacute sclerosing panencephalitis (SSPE) patients who presented with a wide spectrum of repetitive motor behaviors and vocalizations.

RESULTS

Repetitive motor behaviors involved the upper limbs in all patients and lower limbs in 3 patients. The repetitive movements in the upper limbs were clapping, finger-clicking, hand rubbing, flailing, and dystonic posturing. In the lower limbs, the repetitive movements were rubbing with the heel, pelvic thrusting with flexion extension of the leg, and foot tapping. The spectrum of vocalizations included palilalia, whistling, grunting with spitting, and pathological crying. Repetitive behaviors were the presenting features in 2 patients.

CONCLUSIONS

This case series expands the spectrum of repetitive behaviors seen in neurological disorders associated with brain infections. © 2020 International Parkinson and Movement Disorder Society.

Motor stereotypies in adult patients with Tourette syndrome

Aim: Correctly diagnosing repetitive behaviors in patients with Tourette syndrome (TS) can be challenging. The differential diagnosis between tics and stereotypies is of particular importance, because of treatment implications. Methods: We assessed the prevalence and clinical characteristics of stereotypies in a large sample of adult patients with TS attending a specialist clinic. Results: Mild stereotypies were reported by 21/148 patients (14.2%). Patients with stereotypies were significantly more likely to have a comorbid diagnosis of Asperger syndrome, attention-deficit and hyperactivity disorder, and obsessive-compulsive disorder, compared with patients without stereotypies. Multiple linear regression analysis revealed that the presence of Asperger syndrome significantly predicted stereotypy severity. Conclusion: Stereotypies are not rare in adults with TS and other neurodevelopmental conditions, especially Asperger syndrome.

Hand Stereotypies in Rett Syndrome

Researchers from the Rett Syndrome Natural History Study (RNHS) present longitudinal data across the United States of America aimed to characterize hand stereotypies (HS) in this large cohort of patients with Rett syndrome.

The spectrum of involuntary vocalizations in humans: A video atlas

In clinical practice, involuntary vocalizing behaviors are typically associated with Tourette syndrome and other tic disorders. However, they may also be encountered throughout the entire tenor of neuropsychiatry, movement disorders, and neurodevelopmental syndromes. Importantly, involuntary vocalizing behaviors may often constitute a predominant clinical sign, and, therefore, their early recognition and appropriate classification are necessary to guide diagnosis and treatment. Clinical literature and video-documented cases on the topic are surprisingly scarce. Here, we pooled data from 5 expert centers of movement disorders, with instructive video material to cover the entire range of involuntary vocalizations in humans. Medical literature was also reviewed to document the range of possible etiologies associated with the different types of vocalizing behaviors and to explore treatment options. We propose a phenomenological classification of involuntary vocalizations within different categorical domains, including (1) tics and tic-like vocalizations, (2) vocalizations as part of stereotypies, (3) vocalizations as part of dystonia or chorea, (4) continuous vocalizing behaviors such as groaning or grunting, (5) pathological laughter and crying, (6) vocalizations resembling physiological reflexes, and (7) other vocalizations, for example, those associated with exaggerated startle responses, as part of epilepsy and sleep-related phenomena. We provide comprehensive lists of their associated etiologies, including neurodevelopmental, neurodegenerative, neuroimmunological, and structural causes and clinical clues. We then expand on the pathophysiology of the different vocalizing behaviors and comment on available treatment options. Finally, we present an algorithmic approach that covers the wide range of involuntary vocalizations in humans, with the ultimate goal of improving diagnostic accuracy and guiding appropriate treatment. © 2019 The Authors. Movement Disorders published by Wiley Periodicals, Inc. on behalf of International Parkinson and Movement Disorder Society.

Prevalence and determinants of motor stereotypies in autism spectrum disorder: A systematic review and meta-analysis

Stereotypies are frequently reported in people with autism spectrum disorder (ASD) but remain one of the less explained phenomena. We aimed to describe, through a systematic review and a meta-analysis, the prevalence of motor stereotypies in ASD and study the factors that influence this prevalence. Our literature search included MEDLINE, Scopus, and PsycINFO databases. Quality and risk of bias were assessed. Thirty-seven studies were included and the median prevalence of motor stereotypies in ASD was 51.8%, ranging from 21.9% to 97.5%. The most frequent determinants associated with a higher number of stereotypies in ASD were a younger age, lower intelligence quotient, and a greater severity of ASD. Moreover, gender did not seem to influence the prevalence of stereotypies. Meta-analytic analysis showed that lower IQ and autism diagnosis (independent of IQ) are associated with a higher prevalence of motor stereotypies (odds ratio = 2.5 and 4.7, respectively). Limitations of the reviewed literature include the use of convenience samples, with small sizes and heterogeneous inclusion criteria, and the predominance of high-functioning autism individuals.

Hyperkinetic movement disorders in congenital disorders of glycosylation

BACKGROUND AND PURPOSE

Congenital disorders of glycosylation (CDG) represent an increasing number of rare inherited metabolic diseases associated with abnormal glycan metabolism and disease onset in infancy or early childhood. Most CDG are multisystemic diseases mainly affecting the central nervous system. The aim of the current study was to investigate hyperkinetic movement disorders in patients affected by CDG and to characterize phenomenology based on CDG subtypes.

METHODS

Subjects were identified from a cohort of patients with CDG who were referred to the University Hospital of Catania, Italy. Patients were evaluated by neurologists with expertise in movement disorders and videotaped using a standardized protocol.

RESULTS

A variety of hyperkinetic movement disorders was detected in eight unrelated CDG patients. Involuntary movements were generally observed early in childhood, maintaining a clinical stability over time. Distribution ranged from a generalized, especially in younger subjects, to a segmental/multifocal involvement. In patients with phosphomannomutase 2 CDG, the principal movement disorders included dystonia and choreo-athetosis. In patients affected by other CDG types, the movement disorders ranged from pure generalized chorea to mixed movement disorders including dystonia and complex stereotypies.

CONCLUSIONS

Hyperkinetic movement disorder is a key clinical feature in patients with CDG. CDG should be considered in the differential diagnosis of childhood-onset dyskinesia, especially when associated with ataxia, developmental delay, intellectual disability, autism or seizure disorder.

Developmental Motor Profile in Preschool Children with Primary Stereotypic Movement Disorder

Aim

Different neuropsychological dysfunctions have been described in children with primary Stereotypic Movement Disorder (SMD), mainly attention or motor coordination problems. Up to now with no study has evaluated psychomotor functions in preschoolers primary SMD. The aim of this observational study was to gather information on the motor profiles of SMD patients in this age range in comparison with typically developing children.

Patients and Methods

Twenty-six children (four girls) aged 36 to 76 months (mean= 53 ±10) with primary SMD were assessed by a structured evaluation including the Movement Assessment Battery for Children-Second Edition (MABC-2), the Beery-Buktenica Developmental test of Visual-Motor Integration (VMI), the Repetitive Behaviour Scale-Revised (RBS-R), the Motor Severity Stereotypy Scale (MSSS), and the Child Behaviour Checklist (CBCL). The diagnoses of Intellectual Disability or Autism Spectrum Disorder were exclusion criteria from the study. A comparison group of twenty-seven (four girls) typically developing children without stereotypies aged 36 to 59 months (mean= 48 ±7) was also examined.

Results

The MABC-2 total score was lower than 15th percentile in fifteen children with SMD (58%); the worst performances were observed in Balance and Manual Dexterity subtests. The motor coordination score of VMI was lower than 15th percentile in ten children (38%). The majority of the children with low scores at MABC-2 also had low scores at the motor coordination subscale of VMI. MABC-2 standard scores of the clinical group were significantly lower than those of controls on MABC-2 Total, Balance, and Ball Skills subtests.

Conclusion

The finding of widespread dysfunction of gross and fine motor abilities in preschoolers with primary SMD seems to delineate a peculiar phenotype and could provide new approaches to the management of this neurodevelopment disorder.

Tardive dyskinesia update: the syndrome

Tardive dyskinesia is a common iatrogenic neurological and neurobehavioural syndrome associated with the use of antidopaminergic medication, especially antipsychotics. Prior to the introduction of the newer antipsychotics in the 1990s, it was one of the major areas of psychiatric research but interest waned as the new drugs were reputed to have a reduced liability to extrapyramidal adverse effects in general, a claim now discredited by numerous pragmatic research studies. Early small-scale short-term prevalence studies were presented as evidence to support the assumption that patients on the newer drugs did indeed have a lower prevalence of tardive dyskinesia but recent large-scale review of studies with patients exposed for longer suggest that things have not changed. This article presents a clinical overview of a complex and varied syndrome in terms of its phenomenology, epidemiology and risk factors; a companion article will consider treatment. This overview aims to highlight tardive dyskinesia once again, especially to practitioners who have trained in an environment where this was considered mainly in historical terms.

LEARNING OBJECTIVES

•

DECLARATION OF INTEREST

None.

Stereotypic behaviours in frontotemporal dementia and progressive supranuclear palsy

INTRODUCTION

The behavioural variant of frontotemporal dementia (bvFTD), and the Richardson variant of progressive supranuclear palsy (PSP-RS) share several clinical signs and symptoms. Since stereotypic behaviours are fairly common in bvFTD, and are also described in other degenerative dementias including Alzheimer's disease, and parkinsonisms with dementia, we aimed to examine the extent to which stereotypies also characterise PSP-RS.

METHODS

We compared 53 bvFTD patients with 40 demented PSP-RS patients, seen consecutively as outpatients at four Italian Hospitals. Patients were assessed by the Neuropsychiatric Inventory (NPI); Mini-Mental State Examination (MMSE) and Frontal Assessment Battery (FAB) for cognitive functions; Stereotypy Rating Inventory (SRI) for stereotypies; Unified Parkinson's Disease Rating Scale (UPDRS) for motor function; and Activities of Daily Living (ADL) to assess autonomy in daily life.

RESULTS

The groups did not differ for age, illness duration, cognitive functions or total NPI score; PSP-RS had significantly more depressive symptoms and greater motor and autonomy compromise than bvFTD. The groups did not differ significantly on total SRI score, but bvFTD had significantly more cooking and eating stereotypies. Twenty-three (57.5%) PSP-RS and 43 (81%) bvFTD patients had at least one stereotypy; 16/23 (69.5%) PSP-RS and 9/43 (20.9%) bvFTD patients appeared aware of their stereotypies.

CONCLUSION

Stereotypies were common in our demented PSP-RS patients. Further studies on earlier stage non-demented PSP patients are required to ascertain whether stereotypies are characteristic of PSP in general or are confined to PSP-RS, and whether they may be used to suggest a PSP diagnosis early in disease course.

Leg stereotypy syndrome: phenomenology and prevalence

OBJECTIVES

To describe the phenomenology and prevalence of leg stereotypy syndrome (LSS), characterised chiefly by repetitive, rhythmical, stereotypic leg movement, especially when sitting.

METHODS

We sought to characterise LSS in two groups of subjects: (1) general population (GP) group, defined as individuals accompanying patients during their visits to Baylor College of Medicine Parkinson's Disease Center and Movement Disorders Clinic who are not genetically related to the patients; and (2) movement disorders (MD) group, composed of consecutive patients with diagnoses of restless legs syndrome, Parkinson's disease, Tourette syndrome and tardive dyskinesia.

RESULTS

There were 92 participants enrolled in this study; 7% of 57 individuals in the GP group and 17% of those in the MD group met the diagnostic criteria for LSS. The mean age of individuals with LSS was 44.5 (±11.9) years and mean age at onset of LSS was 17.5 (±5.7) years. In half of the individuals, the 'shaking' involved predominantly one leg. All had a positive family history of similar disorder and none had diurnal variation. The seven-item Leg Stereotypy Syndrome Questionnaire was developed as a screening tool to aid in differentiating LSS from other movement disorders.

CONCLUSIONS

LSS is a common condition, occurring in up to 7% of otherwise healthy individuals, and it is even more common in patients with hyperkinetic movement disorders. Although it phenomenologically may overlap with other stereotypic disorders, we argue that it is a distinct, familial, neurological syndrome.

Tourette’s syndrome and its borderland

The Gilles de la Tourette syndrome (or Tourette’s syndrome) has a prevalence of 1% of children with a wide range of severity and associated comorbidities. The last 20 years have seen advances in the understanding of the syndrome’s complex genetics and underlying neurobiology. Investigation with imaging and neurophysiology techniques indicate it is a neurodevelopmental condition with dysfunction of basal ganglia–cortical interactions, which are now also being studied in animal models. There is also increasing evidence for treatments although it often remains difficult to manage. First-line options include neuroleptics, other drugs and specialised behavioural treatments. Deep brain stimulation is an evolving field, not yet fully established. This review focuses on the phenomenology of tics, how to assess and manage the syndrome, and uses examples of atypical cases to explore the characteristics and limits of its clinical spectrum.

Stereotypic Movement Disorders

This review summarizes motor stereotypies in terms of description, prevalence, pathophysiology, diagnosis and management. They are fixed and persistent movements. Stereotypies begin before 3 years of age and continue into adulthood. Primary motor stereotypies occur in children of normal intelligence, whereas secondary stereotypies ensue in the setting of an additional diagnosis such as autism spectrum disorder or other neurologic disorders. They are highly associated with comorbidities such as anxiety, obsessive-compulsive symptoms, inattention, and tics. The pathophysiology of stereotypies involves fronto-striatal overactive dopaminergic pathways, and underactive cholinergic and GABAergic inhibitory pathways. No genetic markers have been identified despite a clear genetic predisposition. Behavioral therapy is the principle treatment. Future studies will focus on identifying genetic markers, and on better understanding the functional and structural neurobiology of these movements.

Updated report on tools to measure outcomes of clinical trials in fragile X syndrome

OBJECTIVE

Fragile X syndrome (FXS) has been the neurodevelopmental disorder with the most active translation of preclinical breakthroughs into clinical trials. This process has led to a critical assessment of outcome measures, which resulted in a comprehensive review published in 2013. Nevertheless, the disappointing outcome of several recent phase III drug trials in FXS, and parallel efforts at evaluating behavioral endpoints for trials in autism spectrum disorder (ASD), has emphasized the need for re-assessing outcome measures and revising recommendations for FXS.

METHODS

After performing an extensive database search (PubMed, Food and Drug Administration (FDA)/National Institutes of Health (NIH)'s www.ClinicalTrials.gov, etc.) to determine progress since 2013, members of the Working Groups who published the 2013 Report evaluated the available outcome measures for FXS and related neurodevelopmental disorders using the COSMIN grading system of levels of evidence. The latter has also been applied to a British survey of endpoints for ASD. In addition, we also generated an informal classification of outcome measures for use in FXS intervention studies as instruments appropriate to detect shorter- or longer-term changes.

RESULTS

To date, a total of 22 double-blind controlled clinical trials in FXS have been identified through www.ClinicalTrials.gov and an extensive literature search. The vast majority of these FDA/NIH-registered clinical trials has been completed between 2008 and 2015 and has targeted the core excitatory/inhibitory imbalance present in FXS and other neurodevelopmental disorders. Limited data exist on reliability and validity for most tools used to measure cognitive, behavioral, and other problems in FXS in these trials and other studies. Overall, evidence for most tools supports a moderate tool quality grading. Data on sensitivity to treatment, currently under evaluation, could improve ratings for some cognitive and behavioral tools. Some progress has also been made at identifying promising biomarkers, mainly on blood-based and neurophysiological measures.

CONCLUSION

Despite the tangible progress in implementing clinical trials in FXS, the increasing data on measurement properties of endpoints, and the ongoing process of new tool development, the vast majority of outcome measures are at the moderate quality level with limited information on reliability, validity, and sensitivity to treatment. This situation is not unique to FXS, since reviews of endpoints for ASD have arrived at similar conclusions. These findings, in conjunction with the predominance of parent-based measures particularly in the behavioral domain, indicate that endpoint development in FXS needs to continue with an emphasis on more objective measures (observational, direct testing, biomarkers) that reflect meaningful improvements in quality of life. A major continuous challenge is the development of measurement tools concurrently with testing drug safety and efficacy in clinical trials.

Adult-onset stereotypical motor behaviors

Stereotypies have been defined as non-goal-directed movement patterns repeated continuously for a period of time in the same form and on multiple occasions, and which are typically distractible. Stereotypical motor behaviors are a common clinical feature of a variety of neurological conditions that affect cortical and subcortical functions, including autism, tardive dyskinesia, excessive dopaminergic treatment of Parkinson's disease and frontotemporal dementia. The main differential diagnosis of stereotypies includes tic disorders, motor mannerisms, compulsion and habit. The pathophysiology of stereotypies may involve the corticostriatal pathways, especially the orbitofrontal and anterior cingulated cortices. Because antipsychotics have long been used to manage stereotypical behaviours in mental retardation, stereotypies that present in isolation tend not to warrant pharmacological intervention, as the benefit-to-risk ratio is not great enough.

Movement Disorders Following Cerebrovascular Lesions in Cerebellar Circuits

Cerebellar circuitry is important to controlling and modifying motor activity. It conducts the coordination and correction of errors in muscle contractions during active movements. Therefore, cerebrovascular lesions of the cerebellum or its pathways can cause diverse movement disorders, such as action tremor, Holmes’ tremor, palatal tremor, asterixis, and dystonia. The pathophysiology of abnormal movements after stroke remains poorly understood. However, due to the current advances in functional neuroimaging, it has recently been described as changes in functional brain networks. This review describes the clinical features and pathophysiological mechanisms in different types of movement disorders following cerebrovascular lesions in the cerebellar circuits.

Intermittent head drops: the differential spectrum

Intermittent Head Drops are episodic head flexion movements that can occur in a number of conditions. Typically, the term has mainly been related to epileptic episodes, but the spectrum of clinical conditions associated with this feature is wide-ranging even if never discussed in detail. By searching the electronic database, we may find that apart from the epileptic conditions, Intermittent Head Drops have been in fact reported in the setting of movement disorders, sleep disorders and even internal medicine disorders, such as Sandifer syndrome. We render an in-depth description of this characteristic phenomenon in different diseases, describing the clinical clues and neurophysiological patterns that may help the clinician to distinguish between the different settings of occurrence.

Parkinsonism, movement disorders and genetics in frontotemporal dementia

Frontotemporal dementia (FTD) refers to a group of clinically and genetically heterogeneous neurodegenerative disorders that are a common cause of adult-onset behavioural and cognitive impairment. FTD often presents in combination with various hyperkinetic or hypokinetic movement disorders, and evidence suggests that various genetic mutations underlie these different presentations. Here, we review the known syndromatic-genetic correlations in FTD. Although no direct genotype-phenotype correlations have been identified, mutations in multiple genes have been associated with various presentations. Mutations in the genes that encode microtubule-associated protein tau (MAPT) and progranulin (PGRN) can manifest as symmetrical parkinsonism, including the phenotypes of Richardson syndrome and corticobasal syndrome (CBS). Expansions in the C9orf72 gene are most frequently associated with familial FTD, typically combined with motor neuron disease, but other manifestations, such as symmetrical parkinsonism, CBS and multiple system atrophy-like presentations, have been described in patients with these mutations. Less common gene mutations, such as those in TARDBP, CHMP2B, VCP, FUS and TREM2, can also present as atypical parkinsonism. The most common hyperkinetic movement disorders in FTD are motor and vocal stereotypies, which have been observed in up to 78% of patients with autopsy-proven FTD. Other hyperkinetic movements, such as chorea, orofacial dyskinesias, myoclonus and dystonia, are also observed in some patients with FTD.