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.

Possible tics diagnosed as stereotypies in patients with severe autism spectrum disorder: a video-based evaluation.

BACKGROUND: The association of stereotypies and tics is not rare in children with severe autism spectrum disorder (ASD). The differential diagnosis between stereotypies and tics in this patient population can be difficult; however, it could be clinically relevant because of treatment implications. METHODS: A total of 108 video recordings of repetitive behaviors in young patients with stereotypies in the context of ASD were reviewed by a movement disorders expert and a trainee, in order to assess the prevalence of possible co-morbid tics. The Modified Rush Videotape Rating Scale (MRVS) was used to rate tic frequency and severity. RESULTS: Out of 27 patients with stereotypies (24 males; mean age 14 years), 18 (67%) reported possible tics. The most frequently observed tics were eye blinking, shoulder shrugging, neck bending, staring, and throat clearing. The mean MRVS score was 5, indicating mild tic severity. The only significant difference between patients with tics and patients without tics was the total number of stereotypies, which was higher in the subgroup of patients without tics (p = 0.01). CONCLUSIONS: Expert review of video-recordings of repetitive behaviors in young patients with ASD and stereotypies suggests the possibility of a relatively high rate of co-morbid tics. These findings need to be integrated with a comprehensive clinical assessment focusing on the diagnostic re-evaluation of heterogeneous motor manifestations.

Sleep Problems and Trajectories of Restricted and Repetitive Behaviors in Children with Neurodevelopmental Disabilities.

Sleep problems are prevalent in children with neurodevelopmental disabilities and are associated with the expression of restricted and repetitive behaviors (RRBs). Children (n = 57) with autism spectrum disorder (ASD, n = 38) or developmental delay (DD, n = 19) participated in multiple assessments of intellectual ability, ASD symptoms, and RRBs (3 timepoints for ASD, 2 for DD). Sleep problems assessed at age 4 via parent report were associated with trajectories of higher-order RRBs (sameness/ritualistic/compulsive behaviors) from age 2-6 in the ASD group, and from age 2-4 in the DD group, even after controlling for intellectual ability, social-affective symptoms, and anxiety. Trajectories of stereotyped/restricted behaviors were unrelated to sleep problems. Sleep problems were associated with trajectories of higher-order (but not lower-order) RRBs in a transdiagnostic sample.

Restricted and Repetitive Behaviors in Males and Females with Fragile X Syndrome: Developmental Trajectories in Toddlers Through Young Adults.

There is limited research on the trajectory of restricted and repetitive behaviors (RRBs) in fragile X syndrome (FXS), with previous studies only examining males and/or examining RRBs as a unitary construct rather than delineating subtypes of RRBs. Thus, we described the trajectory of five subtypes of RRBs in 153 males and females with FXS (aged 1-18 years) with repeated measurement over time (445 total assessments). Multilevel modeling was used to test age-related differences in RRB subtypes between males and females with FXS, controlling for nonverbal IQ. Results showed that lower-order Sensory-Motor behaviors decreased over time for both males and females, while there was no significant change in the higher-order RRBs. The trajectory between males and females differed for Self-Injury.

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.

Nonepileptic, Stereotypical, and Intermittent Symptoms (NESIS) in Patients With Subdural Hematoma: Proposal for a New Clinical Entity With Therapeutic and Prognostic Implications.

BACKGROUND: Transient neurological symptoms (TNS) are frequent in patients with subdural hematomas (SDH) and many will receive a diagnosis of epilepsy despite a negative workup. OBJECTIVE: To explore if patients with TNS and a negative epilepsy workup (cases) evolved differently than those with a positive EEG (controls), which would suggest the existence of alternative etiologies for TNS. METHODS: We performed a single-center, retrospective, case-control study of patients with TNS post-SDH. The demographics and clinical and semiological features of cases and controls were compared. The outcome and response to antiepileptic drugs were also assessed and a scoring system developed to predict negative EEG. RESULTS: Fifty-nine patients with SDH-associated TNS were included (39 cases and 20 controls). Demographic characteristics were comparable in both groups. Dysphasia and prolonged episodes were associated with a negative EEG. Clonic movements, impaired awareness, positive symptomatology, complete response to antiepileptic drugs, and mortality were associated with a positive EEG. Using semiological variables, we created a scoring system with a 96.6% sensitivity and 100% specificity in predicting case group patients. The differences observed between both groups support the existence of an alternative etiology to seizures in our case group. We propose the term NESIS (NonEpileptic, Stereotypical, and Intermittent Symptoms) to refer to this subgroup and hypothesize that TNS in these patients might result from cortical spreading depolarization. CONCLUSION: We describe NESIS as a syndrome experienced by SDH patients with specific prognostic and therapeutic implications. Independent validation of this new entity is now required.

Prevalence and Risk-Markers of Self-Harm in Autistic Children and Adults.

Self-harm is purportedly common in autistic individuals, but under-researched, particularly in younger samples and those without intellectual disability. This study aimed to describe prevalence, profile and correlates of self-harm in autistic individuals without impairments in adaptive functioning. Parents of autistic participants (n = 83) completed questionnaires regarding the presence/topography of self-harm, demographic characteristics, autism severity, age of diagnosis, affect, activity levels and repetitive behaviour. 24.10% of participants engaged in self-harm. Self-harm was associated with significantly higher levels of impulsivity, over-activity, negative affect, compulsive behaviour and insistence on sameness. Low mood and overactivity/impulsivity predicted the presence of self-harm, with the model correctly classifying 82.9% of cases. Findings highlight a role for impaired behavioural inhibition and low mood in the aetiological mechanisms underpinning self-harm in autism.

Overactivity, impulsivity and repetitive behaviour in males with fragile X syndrome: contrasting developmental trajectories in those with and without elevated autism symptoms.

BACKGROUND: Hyperactivity and repetitive behaviour are characteristic features of fragile X syndrome (FXS). However, little is known about the influence of autism symptomatology on how these characteristics develop over time. We investigate the profiles and developmental trajectories of overactivity, impulsivity and repetitive behaviour, in males with FXS over three time points spanning 8 years. METHOD: Participants formed two subgroups, those who displayed elevated symptoms of autism at Time 1 (n = 37; Mage  = 16.32; age range = 6.61-43.51) and those who did not (n = 32; Mage  = 8.43; age range = 8.94-47.49). RESULTS: Participants without elevated symptoms of autism showed a reduction in impulsivity and repetitive questioning over time, whereas those with elevated symptoms of autism did not. Differences between the two subgroups in several topographies of repetitive behaviour emerged at Time 3 only. CONCLUSIONS: These results further understanding of the relationship between autistic phenomenology and behavioural characteristics in FXS.

Attenuated behaviour in Cornelia de Lange and fragile X syndromes.

BACKGROUND: Catatonia-like presentations in people with autism have been increasingly recognised within research and diagnostic guidelines. The recently developed Attenuated Behaviour Questionnaire has identified that attenuated behaviour [autistic catatonia] is very prevalent in people with autism spectrum disorders (ASDs) and associated with repetitive behaviour. In the current study, we investigated attenuated behaviour within two genetic syndromes associated with ASD and examined ASD and repetitive behaviour as longitudinal predictors of attenuated behaviour. METHOD: The Attenuated Behaviour Questionnaire was completed by parents/carers of 33 individuals with Cornelia de Lange syndrome (CdLS) and 69 with fragile X syndrome (FXS). Information collected from the same informants 4 years previously was utilised to examine ASD and repetitive behaviour as predictors of later attenuated behaviour, controlling for age, gender and ability. RESULTS: Catatonia-like attenuated behaviour was reported for individuals with CdLS (30.3%) and FXS (11.6%). Slowed movement was more prevalent in people with CdLS. No other phenotypic differences were observed. Across the two groups, repetitive behaviour predicted the presence of attenuated behaviour 4 years later, after controlling for age, gender and ability. CONCLUSIONS: Attenuated behaviour can be identified in individuals with CdLS and FXS and may have an effect on both adaptive behaviour and quality of life. Repetitive behaviours predicted subsequent risk within both groups and should be assessed by services as part of a pro-active strategy of support.

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.

Brief Report: Repetitive Behaviour Profiles in Williams syndrome: Cross Syndrome Comparisons with Prader-Willi and Down syndromes.

This study describes the profile of repetitive behaviour in individuals with Williams syndrome, utilising cross-syndrome comparisons with people with Prader-Willi and Down syndromes. The Repetitive Behaviour Questionnaire was administered to caregivers of adults with Williams (n = 96), Prader-Willi (n = 103) and Down (n = 78) syndromes. There were few group differences, although participants with Williams syndrome were more likely to show body stereotypies. Individuals with Williams syndrome also showed more hoarding and less tidying behaviours than those with Down syndrome. IQ and adaptive ability were negatively associated with repetitive questioning in people with Williams syndrome. The profile of repetitive behaviour amongst individuals with Williams syndrome was similar to the comparison syndromes. The cognitive mechanisms underlying these behaviours in genetic syndromes warrant further investigation.

Development of Two Dimensional Measures of Restricted and Repetitive Behavior in Parents and Children.

OBJECTIVE: Restricted and repetitive behaviors (RRBs) are a heterogeneous set of behaviors common across a wide range of neurodevelopmental disorders (NDDs) and neuropsychiatric disorders (NPDs) that extend well into the general population. This study introduces 2 dimensional measurements of RRBs for use in typical and clinical populations from infancy to adulthood. METHOD: The Childhood Routines Inventory-Revised (CRI-R) and the Adult Routines Inventory (ARI) were created and administered online to a nationally representative cohort of 3,108 parents with 3,032 children (range 12 months to 17 years 11 months). Twenty-six percent of children and 36% of adults had at least 1 NDD or NPD. RESULTS: Principal axis factoring exploratory analysis showed a 2-factor structure for the 2 instruments (motor behaviors/compulsions and rigidity/insistence on sameness). Analyses for convergent and discriminant validity, internal consistency (Cronbach α ≥ 0.94), and test-retest reliability (r ≥ 0.87) indicated strong psychometric properties. Item response theory analyses indicated strong reliability across the score range for the 2 instruments. RRB rates varied across development, peaking between the preschool and school years. Children with NDDs or NPDs (particularly those with autism spectrum disorder, schizophrenia/bipolar disorder, or obsessive-compulsive disorder/tic disorders) had increased RRBs compared with those with no diagnosis. Parent-child (0.69-0.84) and sibling-sibling (0.76-0.87) intraclass correlations indicated high heritability. Children of parents with an NDD or an NPD exhibited more RRBs compared with children of parents without NDDs or NPDs. CONCLUSION: The CRI-R and ARI are open-source instruments with excellent psychometric properties and will be useful for developmental, clinical, and family genetic studies and for the identification of prodromal conditions involving RRBs.

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.

Parent-Reported Repetitive Behavior in Toddlers on the Autism Spectrum.

Toddlers with autism spectrum disorder (ASD) were assessed on the Repetitive Behavior Scale-Revised (RBS-R), which we found to have acceptable internal consistency. Stereotypical subscale scores showed a negligible association with cognitive level, but correlated more strongly with adaptive and social indicators. Relative to earlier reported RBS-R scores for older age groups, toddlers' scores trended toward higher stereotyped behavior and lower ritualistic/sameness behavior. Our findings on associations with developmental indicators align with those of researchers who used more resource-intensive repetitive behavior measures. The convergence of these findings with those derived from other measurement methods suggests that the RBS-R, a cost effective parent-report measure, is a viable means of assessing repetitive behavior in toddlers with autism.

A Direct Comparison of Self-Injurious and Stereotyped Motor Behavior Between Preschool-Aged Children With and Without Developmental Delays.

OBJECTIVE: To compare the prevalence of self-injurious behavior (SIB) and stereotyped motor behavior (STY) of preschool-aged children with developmental delays (DD group) and their peers without developmental delays (TD group) using a standardized caregiver report scale. METHODS: The Repetitive Behavior Scale-Revised was completed by caregivers of children with developmental delays and their peers without developmental delays. Frequency of occurrence and severity ratings for SIB and STY were compared between groups. RESULTS: SIB and STY were reported more often and at a greater level of severity in the DD group. Older chronological age was associated with more severe STY in the DD group but not the TD group. Gender was not related to STY or SIB for either group. CONCLUSIONS: Differences in STY and SIB were evident between preschoolers with and without DD. Findings are discussed from developmental and behavioral psychology perspectives regarding the expression of repetitive behavior in developmentally at-risk pediatric populations.

Primary complex motor stereotypies in older children and adolescents: clinical features and longitudinal follow-up.

BACKGROUND: Complex motor stereotypies are rhythmic, repetitive, fixed, and purposeless movements that stop with distraction. Once believed to occur only in children with autism spectrum or other developmental disorders, their presence in otherwise typically developing children (primary) has been well-established. In primary complex motor stereotypies, little information is available about the long-term outcome of these movements or existing comorbidities. METHODS: Forty-nine healthy participants (31 boys), ages 9 to 20 years with primary complex motor stereotypies who were previously diagnosed at a pediatric movements disorder clinic, were identified from medical records. Parents or the young adult (if older than age 18), completed a telephone interview evaluating family history, outcome, and comorbidities including attention-deficit hyperactivity disorder, obsessive compulsive disorder, anxiety, and tics/Tourette syndrome. Standardized questionnaires assessing attention-deficit hyperactivity, obsessive compulsive disorder, and anxiety were used to validate parent report of comorbidities. RESULTS: Stereotypy onset occurred before age 3 years in 98%. In all but one individual, stereotypies persisted at the time of phone follow-up (follow-up range: 6.8-20.3 years). Positive family history of complex motor stereotypies was identified in 39%. Most participants (92%) had concern for at least one comorbid disorder, including parent-/patient-reported clinically elevated levels of anxiety (73%), attention-deficit hyperactivity (63%), obsessive compulsive disorder (35%), and tics/Tourette syndrome (22%). CONCLUSION: Primary motor stereotypies typically begin in early childhood and, although reduced in frequency and duration, persist at least through the teenage years. Repetitive movements are associated with a variety of comorbidities that often have a greater functional impact than the stereotypic behavior.

Stereotyped behaviours in children with autism spectrum disorders and atypical development as measured by the BPI-01.

OBJECTIVE: As repetitive behaviours in children with autism spectrum disorders (ASDs) can significantly interfere with one's daily functioning, continued research on these behaviours is needed. METHODS: This study examined the occurrence of repetitive motor movements in toddlers (17-37 months) with ASD and atypical development and the relationship between stereotypies and sensory impairment. RESULTS: Children with ASD (n = 13) exhibited significantly more repetitive behaviours than the non-ASD group (n = 12). Greater percentages of endorsement were evident for the ASD group on nearly all items of the Behaviour Problems Inventory-01 (BPI-01) Stereotypy subscale. More repetitive behaviours tended to co-occur with other stereotypies for the ASD group. A moderate correlation was found between stereotypy severity and sensory deficits. CONCLUSION: These findings suggest that stereotyped behaviours can be identified at very young ages, negatively affect the behavioural presentation of those with ASDs and should be considered when developing treatment plans.

Prevalencia de estereotipias en pacientes sin enfermedades crónicas / Prevalence of stereotypies in patients without chronic diseases

Introducción: Las estereotipias han sido descritas en niños con trastornos del desarrollo pero su prevalencia y características en niños con desarrollo madurativo normal no es conocida. Objetivo: Estimar la prevalencia de estereotipias en niños sin enfermedades crónicas y describir sus características clínicas y epidemiológicas Pacientes y Métodos: Estudio de corte transversal. Se aplicó una encuesta a madres de niños recién nacidos hasta niños de 12 años que concurrieron a los consultorios externos con muestreo consecutivo y no aleatori-zado. La encuesta fue analizada previamente en un subgrupo de madres. Resultados: Se completaron 406 encuestas, en el 57 por ciento se refirieron estereotipias y las más frecuentes fueron chuparse los dedos (21,8 por ciento) y comerse las uñas (20 por ciento). El análisis multivariado identificó mayor probabilidad de presentar estereotipias en niños con antecedentes de esterotipia en los padres, situaciones de estrés y madres mayores de 35 años. Conclusión: Las estereotipias tienen una elevada prevalencia en los niños y son más frecuentes en niños con antecedentes familiares de estereotipias, situaciones de estrés y en niños con madres de mayor edad.

Background: Stereotypies have been described in children with developmental disorders but their prevalence and characteristics in developmentally normal children is unknown. Objective: To estimate the prevalence of stereotypies in children without chronic diseases and describe their clinical and epidemiological characteristics. Patients and Methods: A Cross-sectional study was performed. Mothers of children aged from birth to 12 years, who attended the outpatient clinic, answered survey questions. Results: 406 surveys were completed; stereotypies were observed in 57 percent of patients, among the most frequent, finger sucking (21.8 percent) and nail biting (20 percent). A multivariate analysis identified that stereotypies are more likely in children with a history of stereotypy in parents, under stressful environments, and with mothers over 35 years old. Conclusion: Stereo-typies showed a high prevalence in this study, most frequently in those children under stressful environments, mothers older than 35 years, and affected parents.

Language use and stereotyping: the role of approach and avoidance motivation goals

The use of more abstract language to describe expected behaviors as opposed to unexpected behaviors has traditionally been considered a way of stereotype maintenance. This tendency is known as linguistic expectancy bias. Two experiments examined the influence of approach and avoidance motivational orientations on the production of this linguistic expectancy bias. It was predicted that approach strategic orientation is likely to describe expectancy consistent behaviors at a higher level of linguistic abstraction than expectancy inconsistent behaviors. In contrast, avoidance strategic orientation is likely to describe both expectancy consistent behaviors and expectancy inconsistent behaviors at a lower level of linguistic abstraction, thus facilitating the disappearance of linguistic expectancy bias. Two experiments confirmed these expectations, using strategic orientation manipulations based either on communication goals or on motor action, and measuring linguistic abstraction either on forced-choice answer format or on free descriptions. Implications for the generalisation of linguistic expectancy bias are discussed (AU)

El uso de un lenguaje más abstracto para describir los comportamientos congruentes con las expectativas que los comportamientos incongruentes con las expectativas es una forma de mantener los estereotipos. Esta tendencia se conoce como el sesgo lingüístico de expectativa. Dos experimentos analizan la influencia de las orientaciones motivacionales de aproximación y evitación en la producción del sesgo lingüístico de expectativa. Se predijo que la orientación estratégica de aproximación promovería que comportamientos consistentes con la expectativa se describiesen con un mayor nivel de abstracción lingüística que los comportamientos inconsistentes con la expectativa. En cambio, la orientación estratégica de evitación induciría a que tanto los comportamientos consistentes como los inconsistentes con las expectativas se describiesen a un menor nivel de abstracción, facilitando con ello la desaparición del sesgo lingüístico de expectativa. Los dos experimentos que se presentan confirmaron dichas predicciones utilizando manipulaciones de orientación estratégica de aproximación y evitación formuladas en forma de metas comunicativas y en forma de acción motora. Además, se midió la abstracción lingüística tanto en formato de respuesta de elección múltiple como en descripción libre. El artículo debate las implicaciones de los estudios para la generalización del sesgo lingüístico de expectativa (AU)

Stereotypic behaviors in degenerative dementias.

Stereotypies are simple or complex involuntary/unvoluntary behaviors, common in fronto-temporal dementia (FTD), but not studied in other types of degenerative dementias. The aim was to investigate stereotypy frequency and type in patients with FTD, Alzheimer's disease (AD), progressive supranuclear palsy (PSP) and Parkinson's disease with dementia (PDD) in a multicenter observational study; and to investigate the relation of stereotypies to cognitive, behavioral and motor impairment. One hundred fifty-five consecutive outpatients (45 AD, 40 FTD, 35 PSP and 35 PDD) were studied in four hospitals in northern Italy. Stereotypies were examined by the five-domain Stereotypy Rating Inventory. Cognition was examined by the Mini Mental State and Frontal Assessment Battery, neuropsychiatric symptoms by the Neuropsychiatric Inventory, and motor impairment and invalidity by the Unified Parkinson's Disease Rating Scale part III, and activities of daily living. Stereotypies were present in all groups. FTD and PDD had the greatest frequency of one-domain stereotypies; FTD also had the greatest frequency of two-or-more domain stereotypies; movement stereotypies were the most common stereotypies in all groups. AD patients had fewer stereotypies than the other groups. Stereotypies are not exclusive to FTD, but are also fairly common in PSP and PDD, though less so in AD. Stereotypies may be underpinned by dysfunctional striato-frontal circuits, known to be damaged in PSP and PDD, as well as FTD.