Premonitory Sensations Research Articles

Functional Tic-Like Behaviors: A Common Comorbidity in Patients with Tourette Syndrome.

Comorbid functional tic-like behaviors (FTB) have been described only rarely in patients with Tourette syndrome (TS). We present the first large sample of patients suffering from TS and FTB to raise awareness of this clinical presentation and to guide how to differentiate one from the other. We analyzed clinical data of 71 patients (n = 27 [38.0%] female, mean age: 21.5, range: 11-55) with TS + FTB. In the majority of patients, FTB started abruptly on average 15 years after tic onset with "treatment-resistant" complex movements and ("coprophenomena-like") vocalizations preceded by timely related psychological stressors. Psychological evaluation revealed evidence for internal conflicts (79%), emotional dysregulation (56%), and maintaining factors (70%). About one third of patients had a positive history for further medically unexplained symptoms. Compared to a large TS sample (n = 1032), patients with TS + FTB were more likely to be female, and presented significantly more common with "coprophenomena-like" symptoms, atypical influential factors, atypical descriptions of premonitory sensations, and higher rates of comorbid obsessive-compulsive disorder and "self-injurious" behavior. Based on our data it can be assumed that FTB is a common comorbidity in TS, similar to functional overlay in other movement disorders and epilepsy. Before classifying a patient as suffering from treatment-resistant TS, FTB should be ruled out.

Elevated representational similarity of voluntary action and inhibition in Tourette syndrome.

Many people with Tourette syndrome are able to volitionally suppress tics, under certain circumstances. To understand better the neural mechanisms that underlie this ability, we used functional magnetic resonance neuroimaging to track regional brain activity during performance of an intentional inhibition task. On some trials, Tourette syndrome and comparison participants internally chose to make or withhold a motor action (a button press), while on other trials, they followed 'Go' and 'NoGo' instructions to make or withhold the same action. Using representational similarity analysis, a functional magnetic resonance neuroimaging multivariate pattern analysis technique, we assessed how Tourette syndrome and comparison participants differed in neural activity when choosing to make or to withhold an action, relative to externally cued responses on Go and NoGo trials. Analyses were pre-registered, and the data and code are publicly available. We considered similarity of action representations within regions implicated as critical to motor action release or inhibition and to symptom expression in Tourette syndrome, namely the pre-supplementary motor area, inferior frontal gyrus, insula, caudate nucleus and primary motor cortex. Strikingly, in the Tourette syndrome compared to the comparison group, neural activity within the pre-supplementary motor area displayed greater representational similarity across all action types. Within the pre-supplementary motor area, there was lower response-specific differentiation of activity relating to action and inhibition plans and to internally chosen and externally cued actions, implicating the region as a functional nexus in the symptomatology of Tourette syndrome. Correspondingly, patients with Tourette syndrome may experience volitional tic suppression as an effortful and tiring process because, at the top of the putative motor decision hierarchy, activity within the population of neurons facilitating action is overly similar to activity within the population of neurons promoting inhibition. However, not all pre-supplementary motor area group differences survived correction for multiple comparisons. Group differences in representational similarity were also present in the primary motor cortex. Here, representations of internally chosen and externally cued inhibition were more differentiated in the Tourette syndrome group than in the comparison group, potentially a consequence of a weaker voluntary capacity earlier in the motor hierarchy to suppress actions proactively. Tic severity and premonitory sensations correlated with primary motor cortex and caudate nucleus representational similarity, but these effects did not survive correction for multiple comparisons. In summary, more rigid pre-supplementary motor area neural coding across action categories may constitute a central feature of Tourette syndrome, which can account for patients' experience of 'unvoluntary' tics and effortful tic suppression.

Rapid Onset Functional Tic-Like Behaviors in Young Females During the COVID-19 Pandemic.

Rapid Onset Functional Tic-Like Behaviors in Young Females During the COVID-19 Pandemic.

Urge Intolerance and Impairment Among Youth with Tourette's and Chronic Tic Disorders.

Individuals with Tourette's Disorder and Persistent Tic Disorders (TD) often experience premonitory urges-aversive sensations that precede tics and are relieved by tic expression. Given its role in the neurobehavioral model of TD, understanding factors that influence premonitory urges and associated relief can advance understanding of urge phenomenology and optimize treatments for individuals with TD. This study examined whether the novel construct of urge intolerance-difficulty tolerating premonitory urges-predicted tic severity and tic-related disability. Participants included 75 youth with TD and their caregivers. Assessments characterized tic severity, premonitory urge, distress tolerance, internalizing symptoms, and tic-related disability. Structural equation modeling revealed that higher levels of urge intolerance predicted greater levels of tic-related disability. Furthermore, the relationship between urge intolerance and tic-related disability was more robust for youth with clinically-elevated levels of internalizing symptoms. While further investigation is needed, urge intolerance represents a promising treatment target to improve tic-related disability in youth with TD.

Amplified engagement of prefrontal cortex during control of voluntary action in Tourette syndrome.

Tourette syndrome is characterized by ‘unvoluntary’ tics, which are compulsive, yet often temporarily suppressible. The inferior frontal gyrus is implicated in motor control, including inhibition of pre-potent actions through influences on downstream subcortical and motor regions. Although tic suppression in Tourette syndrome also engages the inferior frontal gyrus, it is unclear whether such prefrontal control of action is also dysfunctional: Tic suppression studies do not permit comparison with control groups, and neuroimaging studies of motor inhibition can be confounded by the concurrent expression or suppression of tics. Here, patients with Tourette syndrome were directly compared to control participants when performing an intentional inhibition task during functional MRI. Tic expression was recorded throughout for removal from statistical models. Participants were instructed to make a button press in response to Go cues, withhold responses to NoGo cues, and decide whether to press or withhold to ‘Choose’ cues. Overall performance was similar between groups, for both intentional inhibition rates (% Choose-Go) and reactive NoGo inhibition commission errors. A subliminal face prime elicited no additional effects on intentional or reactive inhibition. Across participants, the task activated prefrontal and motor cortices and subcortical nuclei, including pre-supplementary motor area, inferior frontal gyrus, insula, caudate nucleus, thalamus and primary motor cortex. In Tourette syndrome, activity was elevated in the inferior frontal gyrus, insula and basal ganglia, most notably within the right inferior frontal gyrus during voluntary action and inhibition (Choose-Go and Choose-NoGo), and reactive inhibition (NoGo-correct). Anatomically, the locus of this inferior frontal gyrus hyperactivation during control of voluntary action matched that previously reported for tic suppression. In Tourette syndrome, activity within the caudate nucleus was also enhanced during both intentional (Choose-NoGo) and reactive (NoGo-correct) inhibition. Strikingly, despite the absence of overt motor behaviour, primary motor cortex activity increased in patients with Tourette syndrome but decreased in controls during both reactive and intentional inhibition. Additionally, severity of premonitory sensations scaled with functional connectivity of the pre-supplementary motor area to the caudate nucleus, globus pallidus and thalamus when choosing to respond (Choose-Go). Together, these results suggest that patients with Tourette syndrome use equivalent prefrontal mechanisms to suppress tics and withhold non-tic actions, but require greater inferior frontal gyrus engagement than controls to overcome motor drive from hyperactive downstream regions, notably primary motor cortex. Moreover, premonitory sensations may cue midline motor regions to generate tics through interactions with the basal ganglia.

Sex and psychiatric comorbidity correlates of the premonitory urge for tic scale in youth with persistent tic disorders.

The premonitory urge for tics scale (PUTS) is a common self-report measure of premonitory sensations preceding tics. The present study aimed to examine the internal consistency and concurrent validity of the PUTS by sex and psychiatric comorbidity status; and explored interactions between sex and psychiatric comorbidity in predicting premonitory urge and tic symptom severity. Seventy-four youth and young adults with persistent tic disorders completed the PUTS, while their parents completed the parent tic questionnaire (PTQ) and a demographic measure. Independent samples t-tests revealed no significant sex differences in PUTS items or total score. The PUTS total score also did not significantly differ between participants with and without attention-deficit hyperactivity disorder (ADHD) and/or obsessive-compulsive disorder (OCD) comorbidity. Internal consistency did not significantly differ between females (α = 0.85) and males (α = 0.75), and those with comorbid ADHD and/or OCD (α = 0.83) relative to those without (α = 0.69). With respect to concurrent validity, the PUTS total was significantly correlated with PTQ tic frequency, intensity, number, and severity for males but not for females. Among those with ADHD and/or OCD, the PUTS total score was correlated significantly and strongly with tic number and moderately with tic intensity. Interactions between sex and psychiatric comorbidity performed using 2 × 2 analysis of variance did not significantly predict the PUTS total or PTQ subscale scores. Findings suggest sex and comorbidity status may influence premonitory urge expression. Results have implications for understanding and measurement of the premonitory urge.

Swearing, Cursing, Coprophenomena

Abstract. In healthy individuals, expletive language occurs as swearing/cursing, in patients with Tourette syndrome as coprolalia. Swearing and coprolalia thus have been likened as two ends of a continuum. Both occur apparently automatically, are triggered by emotional activation, e. g., by stress or pain, and are typically instantiations of nonpropositional language. Neurobiologically, a thalamo-cortical-limbic dysfunction is discussed. However, there are notable differences between the two: While swearing fulfills intra- and inter-individual functions coprolalia seems less functional and can result in considerable social stigma because of their occurrence in socially inappropriate situations. Patients with coprolalia report antecedents, especially feelings of urge and premonitory sensations, like itches or tingles. Finally, coprolalia seems to extend to more serious and insulting expressions compared to “everyday” swearwords.

A Bayesian Account of the Sensory-Motor Interactions Underlying Symptoms of Tourette Syndrome.

Tourette syndrome is a hyperkinetic movement disorder. Characteristic features include tics, recurrent movements that are experienced as compulsive and “unwilled”; uncomfortable premonitory sensations that resolve through tic release; and often, the ability to suppress tics temporarily. We demonstrate how these symptoms and features can be understood in terms of aberrant predictive (Bayesian) processing in hierarchical neural systems, explaining specifically: why tics arise, their “unvoluntary” nature, how premonitory sensations emerge, and why tic suppression works—sometimes. In our model, premonitory sensations and tics are generated through over-precise priors for sensation and action within somatomotor regions of the striatum. Abnormally high precision of priors arises through the dysfunctional synaptic integration of cortical inputs. These priors for sensation and action are projected into primary sensory and motor areas, triggering premonitory sensations and tics, which in turn elicit prediction errors for unexpected feelings and movements. We propose experimental paradigms to validate this Bayesian account of tics. Our model integrates behavioural, neuroimaging, and computational approaches to provide mechanistic insight into the pathophysiological basis of Tourette syndrome.

Dimensions of interoception predict premonitory urges and tic severity in Tourette syndrome

Interoceptive processes in Tourette syndrome may foster the premonitory urges that commonly precede tics. Twenty-one adults with TS and 22 controls completed heartbeat tracking and discrimination tasks. Three dimensions of interoception were examined: objective accuracy, metacognitive awareness, and subjective (self-report) sensibility. Trait interoceptive prediction error was calculated as the discrepancy between accuracy and sensibility. Participants with TS had numerically lower interoceptive accuracy on the heartbeat tracking task, and increased self-reported interoceptive sensibility. While these group differences were not significant, the discrepancy between lower interoceptive accuracy and heightened sensibility, i.e. the trait interoceptive prediction error, was significantly greater in TS compared to controls. This suggests a heightened higher-order sensitivity to bodily sensations in TS, relative to a noisier perceptual representation of afferent bodily signals. Moreover, interoceptive sensibility predicted the severity of premonitory sensations and tics. This suggests interventions that work to align dimensions of interoceptive experience in TS hold therapeutic potential.

Face perception enhances insula and motor network reactivity in Tourette syndrome.

Tourette syndrome is a neurodevelopmental disorder, characterized by motor and phonic tics. Tics are typically experienced as avolitional, compulsive, and associated with premonitory urges. They are exacerbated by stress and can be triggered by external stimuli, including social cues like the actions and facial expressions of others. Importantly, emotional social stimuli, with angry facial stimuli potentially the most potent social threat cue, also trigger behavioural reactions in healthy individuals, suggesting that such mechanisms may be particularly sensitive in people with Tourette syndrome. Twenty-one participants with Tourette syndrome and 21 healthy controls underwent functional MRI while viewing faces wearing either neutral or angry expressions to quantify group differences in neural activity associated with processing social information. Simultaneous video recordings of participants during neuroimaging enabled us to model confounding effects of tics on task-related responses to the processing of faces. In both Tourette syndrome and control participants, face stimuli evoked enhanced activation within canonical face perception regions, including the occipital face area and fusiform face area. However, the Tourette syndrome group showed additional responses within the anterior insula to both neutral and angry faces. Functional connectivity during face viewing was then examined in a series of psychophysiological interactions. In participants with Tourette syndrome, the insula showed functional connectivity with a set of cortical regions previously implicated in tic generation: the presupplementary motor area, premotor cortex, primary motor cortex, and the putamen. Furthermore, insula functional connectivity with the globus pallidus and thalamus varied in proportion to tic severity, while supplementary motor area connectivity varied in proportion to premonitory sensations, with insula connectivity to these regions increasing to a greater extent in patients with worse symptom severity. In addition, the occipital face area showed increased functional connectivity in Tourette syndrome participants with posterior cortical regions, including primary somatosensory cortex, and occipital face area connectivity with primary somatosensory and primary motor cortices varied in proportion to tic severity. There were no significant psychophysiological interactions in controls. These findings highlight a potential mechanism in Tourette syndrome through which heightened representation within insular cortex of embodied affective social information may impact the reactivity of subcortical motor pathways, supporting programmed motor actions that are causally implicated in tic generation. Medicinal and psychological therapies that focus on reducing insular hyper-reactivity to social stimuli may have potential benefit for tic reduction in people with Tourette syndrome.

Subjective embodiment during the rubber hand illusion predicts severity of premonitory sensations and tics in Tourette Syndrome.

In Tourette Syndrome, the expression of tics and commonly preceding premonitory sensations is associated with perturbed subjective feelings of self-control and agency. We compared responses to the Rubber Hand Illusion in 23 adults with TS and 22 controls. Both TS and control participants reported equivalent subjective embodiment of the artificial hand: feelings of ownership, location, and agency were greater during synchronous visuo-tactile stimulation, compared to asynchronous. However, individuals with TS did not manifest greater proprioceptive drift, an objective marker of embodiment observed in controls. An 'embodiment prediction error' index of the difference between subjective embodiment and objective proprioceptive drift correlated with severity of premonitory sensations. Feelings of ownership also correlated with premonitory sensation severity, and feelings of agency with tic severity. These findings suggest that subjective bodily ownership, as measured by the rubber hand illusion, contributes to susceptibility to the premonitory sensations that may be a precipitating factor in tics.

The temporal relationship between premonitory urges and covert compulsions in patients with obsessive-compulsive disorder

Recent studies in patients with obsessive-compulsive disorder (OCD) have shown that many compulsions are associated with urges rather than obsessions. Premonitory urges are uncomfortable sensory feelings or a rising inner tension, often likened to the urge to scratch, yawn or blink. We studied premonitory urges preceding mental compulsions in 19 patients with OCD and preceding eye blinks in 16 healthy controls. Urge intensity was assessed continuously over 20 min using a real-time urge intensity monitor; compulsions and blinks were measured as discrete events in a free compulsion/blinking and a compulsion/blink suppression condition. Urge intensity showed an inverted U-shaped relationship (increase then decrease) around compulsions within a time-window of approximately 60 s in patients with OCD and within 13 s around blinks in healthy controls. Urge intensity was higher during compulsion / blink suppression and varied more independently of compulsion execution in patients with OCD. There is a close temporal relationship between premonitory sensations and compulsion execution that changes when compulsions are suppressed, indicating that urge intensity might drive the execution of and is then alleviated by compulsions. Suppression weakens the association between urge intensity and compulsion execution.

Premonitory Urge for Tics Scale (PUTS): replication and extension of psychometric properties in youth with chronic tic disorders (CTDs).

Individuals with chronic tic disorders (CTDs) frequently describe aversive subjective sensory sensations that precede their tics. The first aim of the present study was to explore the psychometric properties of a standardized self-report measure to assess premonitory urges in CTDs, The Premonitory Urge for Tics Scale (PUTS), by replicating the analyses of Woods et al. (J Dev Behav Pediatr 26:397-403, 2005) using a sample twice the size of theirs. The second aim was to conduct an exploratory factor analysis of the PUTS. Eighty-four youth with CTDs, recruited from a pediatric OCD and tic specialty clinic, completed the PUTS while their caregivers completed The Parent Tic Questionnaire (PTQ) and a demographic measure. Consistent with (Woods et al. J Dev Behav Pediatr 26:397-403, 2005), the PUTS was found to be internally consistent (α=0.82) and significantly correlated with overall tic severity as measured by the PTQ (r=0.24, p<0.05) as well as the PTQ number (r=0.34, p<0.01) and intensity (r=0.24, p<0.05) subscales. A factor-analysis of the PUTS revealed a two-factor solution with one factor capturing the quality of premonitory sensations while the other factor assessed the overall intensity of the urges. These results support the use of the PUTS in reliably measuring premonitory urges, particularly in children over the age of 10years. Additionally, these findings highlight that urges are uniformly reported across gender and age and are more closely associated with number of tics than the frequency or intensity of tics.

Proline-rich Transmembrane Protein 2 Gene Mutation in a Sporadic Paroxysmal Kinesigenic Dyskinesia.

Dear Sir, A 12-year-old boy presented with paroxysmal events for the last 3 months. He had no adverse perinatal events and was developmentally normal. He experienced brief episodes of abnormal posturing of upper and lower limbs, usually on the right side. These episodes were triggered by sudden movements like sudden rise from sitting or lying position and sometimes by startle. There was absent premonitory sensation, preserved consciousness during the events, and no “postictal” drowsiness. The frequency was variable from 3 to 5 episodes/day to once in 2–3 days. There were no other body movements, myoclonus, dance-like movements, neuroregression, and hearing or vision impairment. There was no history of headaches or seizures in infancy. The family history was unremarkable for any seizures, movement disorder, or migraine. Examination was normal. Magnetic resonance imaging of his brain and his “interictal” electroencephalogram (EEG) were normal. He had poor response to oral valproate, started by a local practitioner. A possibility of paroxysmal kinesigenic dyskinesia (PKD) was considered in view of sudden movement/startle-induced paroxysmal dyskinesia. He had complete resolution of symptoms on oxcarbazepine. By direct sequencing of the entire coding region and exon-intron boundaries of the proline-rich transmembrane protein 2 (PRRT2) gene, the heterozygous mutation, c. 649dupC p. Arg217Profs*8 mutation, was identified in the patient. This mutation has been previously reported in patients with PKD from several parts of the world. PKD or DYT10, a rare movement disorder, may be sporadic or familial (autosomal dominant with incomplete penetrance). PRRT2 is the major gene responsible for PKD. The encoded protein, PRRT2, has presynaptic localization and appears to be involved in exocytosis and neurotransmitter release. The classical PKD phenotype is characterized by onset in childhood or adolescence; frequent brief attacks of dystonia, choreoathetosis, and/or ballismus with preserved consciousness; precipitation by sudden voluntary movements or startle; frequent aura; normal interictal neurological examination; and excellent response to anticonvulsants. The most effective drugs in PKD are voltage-gated sodium channel blockers (carbamazepine, oxcarbazepine, phenytoin, lacosamide). The common misdiagnosis is epilepsy, but preserved consciousness during the attacks, absence of postictal state, and absence of “ictal” EEG abnormalities favor PKD. The spectrum of PRRT2-associated diseases also includes benign familial infantile seizures, infantile convulsions with choreoathetosis, episodic ataxia, hemiplegic migraine, and benign paroxysmal torticollis of infancy.

Approaches to the Diagnosis and Treatment of OCD with Comorbid Tic Disorders

Bidirectional overlap has long been described between obsessive–compulsive disorder (OCD) and tic disorders. Similar features, including underlying neurobiological genesis in frontal-striatal circuitry, familiality, relatively early onset, waxing and waning course, and overlapping phenomenology in repetitive behaviors, suggest different variations of the same disorder. Nevertheless, some differences have been described between OCD and tic disorders: tics begin early in childhood and typically attenuate or remit by late adolescence, whereas OCD tends to onset later and persist, and tic disorders are far more common in males than is the case in OCD. Individuals with OCD plus comorbid tics may represent a specific sub-type of OCD or tic disorders, and possess some important phenomenological differences from those with OCD without tics; for example, tic-related OCD tends to have earlier onset, higher prevalence in males, prominent symmetry, evening-up, counting, and “just-right” phenomenology, when compared with non-tic-related OCD. Recent DSM-5 classification changes now recognize presence of tics as a specifier in diagnosis of OCD; despite a 40 % prevalence rate of comorbid tics in childhood-onset OCD, there is still little data regarding risk factors, validated distinguishing features, course and treatment of this diagnostic group. Prominence of premonitory sensory phenomena, urges or sensations experienced prior to the repetitive behaviors, is no longer thought to distinguish complex motor tics from compulsions. Well established treatments of OCD include cognitive behavioral interventions and pharmacotherapy, specifically the serotonin re-uptake inhibitors (SRIs); although these treatments are also beneficial in tic-related OCD, some studies suggest that at least for pharmacotherapy, SRIs may not be as effective in OCD patients with comorbid tics. Given the frequent overlap of OCD and tics, and the recent designation of tic-related OCD as an OCD specifier, more investigation of the comorbid subtype is clearly needed.

Late-Onset Psychogenic Chronic Phonic-Tics.

BackgroundTics beginning in late adulthood often have an identifiable etiology. Psychogenic tics with onset around 60 years of age are rarely described in the literature.Case reportA 67-year-old female had experienced phonic tics for 8 years. Episodes occurred without premonitory sensations and precipitant factors, and she could not suppress them. She had no history of childhood tic disorder, and secondary causes of tics were excluded. She was diagnosed with psychogenic tics and treated with quetiapine with mild improvement.DiscussionWhen physicians are faced with no identifiable cause of tics combined with certain clinical clues, a psychogenic disorder must be suspected.

Therapeutic Developments for Tics and Myoclonus.

Tics and myoclonus are phenomenologically similar given that both are jerk-like movements, but, in contrast to myoclonus, tics are often preceded by premonitory sensations and are typically associated with a variety of behavioral comorbidities, including attention deficit and obsessive-compulsive disorder. There are many other clinical features that help differentiate these two hyperkinetic disorders. Whereas behavioral and antidopaminergic therapies are most effective in the management of tics, clonazepam, other anticonvulsants, and serotonergic drugs are often used to control myoclonic movements. Botulinum toxin may also be helpful in focal tics and in segmental forms of myoclonus. DBS plays an increasingly important role in the treatment of these disorders, particularly when they are generalized and are disabling despite optimal medical therapy.

Premonitory Urges in Patients with Gilles de la Tourette Syndrome: An Italian Translation and a 7-Year Follow-up.

Premonitory sensations or urges (PUs) are described as characteristic sensory phenomena preceding tics, which are often described as unpleasant. They occur in 90% of patients affected by Gilles de la Tourette Syndrome (GTS). They may be localized (around the area of tic) or generalized (covering a wide area of the body). The PUs can be measured by the Premonitory Urge for Tics Scale (PUTS). In this study we translated the PUTS scale into Italian and then assessed children and adolescents/young people (CYP) with GTS using the scale. GTS patients were assessed at the initial interview and after 7 years to evaluate the PUs, and the correlations of the PUTS scores with tic severity, severity of comorbid disorders (obsessive-compulsive disorder [OCD], attention-deficit/hyperactivity disorder [ADHD]), and a variety of coexisting psychopathologies. A total of 95 patients were studied. We successfully translated the PUTS into Italian, and our results indicated that our translated version had good psychometric properties. Results demonstrated that the CYP had PUs at both interviews, but that older CYP were more consistent in reporting PUs than younger CYP (i.e., PUTS scores increased with age). We found no correlations between PUTS score and tic severity at either interview. We found a statistical significant correlation between PUTS score and obsessive-compulsive symptoms (OCS) at both interviews; Moreover both the PUTS and Children's Yale-Brown Obsessive Compulsive Scale (CY-BOCS) scores increased significantly, whereas the Yale Global Tic Severity Rating Scale (YGTSS) score decreased significantly. We found no relationships between PUTS scores and anxiety, depression, ADHD, and externalizing/internalizing behavioral scores. Our results suggest the the Italian translation of the PUTS has good psychometric properties. Although both younger (<10 years of age) and older CYP (≤ 10 years of age) reported PUs, the scores at the initial interview were statistically significantly lower than at follow-up. Moreover, in CYP >10 years of age, the PUs correlated with obsessions and compulsions (CY-BOCS scores).

A POSITIVE DIAGNOSIS OF FUNCTIONAL (PSYCHOGENIC) TICS

ObjectiveFunctional tics, also called psychogenic tics or pseudo-tics, are difficult to diagnose because of the lack of diagnostic criteria and their clinical similarities to organic tics. The aim of the...

A positive diagnosis of functional (psychogenic) tics.

Functional tics, also called psychogenic tics or pseudo-tics, are difficult to diagnose because of the lack of diagnostic criteria and their clinical similarities to organic tics. The aim of the present study was to report a case series of patients with documented functional tics and to describe their clinical characteristics, risk factors and psychiatric comorbidity. Also clinical tips are suggested which might help the differential diagnosis in clinical practice. Eleven patients (mean age at onset 37.2, SD 13.5; three females) were included with a documented or clinically established diagnosis of functional tics, according to consultant neurologists who have specific expertise in functional movement disorders or in tic disorders. Adult onset, absent family history of tics, inability to suppress the movements, lack of premonitory sensations, absence of pali-, echo- and copro-phenomena, presence of blocking tics, the lack of the typical rostrocaudal tic distribution and the coexistence of other functional movement disorders were common in our patients. Our data suggest that functional tics can be differentiated from organic tics on clinical grounds, although it is also accepted that this distinction can be difficult in certain cases. Clinical clues from history and examination described here might help to identify patients with functional tics.