ORIGINAL ARTICLE

A positive diagnosis of functional (psychogenic) tics B. Demartinia,b, L. Ricciardia,c, I. Pareesa, C. Ganosa,d, K. P. Bhatiaa and M. J. Edwardsa Sobell Department, UCL Institute of Neurology, London, UK; bDepartment of Psychiatry, San Paolo Hospital and University of Milan, Milan; cDepartment of Clinical and Experimental Medicine, University of Messina, Messina, Italy; and dDepartment of Neurology, University Medical Center Hamburg-Eppendorf (UKE), Hamburg, Germany

Keywords:

functional, psychogenic, tics Received 7 April 2014 Accepted 7 October 2014 European Journal of Neurology 2014, 0: 1–7 doi:10.1111/ene.12609

Background and purpose: 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. Methods and results: 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. Conclusions: 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.

Introduction Functional tics are part of the wide spectrum of functional movement disorders (FMDs), a common cause of movement disorders in clinical practice [1]. Nomenclature in this field remains problematic: a variety of terms have been used to describe this phenomenon, including psychogenic tics, pseudo-tics or non-organic tics. In this paper the straightforward term functional tics is used to describe the specific symptom and to avoid making assumptions about its aetiology (which is still poorly defined) [2]. Functional tics are rarely reported, compared with functional tremor, dystonia or myoclonus [3–5]. In one of the largest reported series, functional tics accounted for only 2% (29/1245) of FMDs [6]. Correspondence: B. Demartini, Sobell Department, UCL Institute of Neurology, Queen Square, London WC1N 3BG, UK (tel.: +44 84 51555000; fax: +44 20 7278936; e-mail: [email protected]).

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It is possible that functional tics are simply a rare phenomenon, but it is also possible that patients are not correctly identified due to the difficulty in making the diagnosis. The diagnosis of functional tics is challenging because the commonly used criteria that differentiate FMDs from organic movement disorders (sudden onset, distractibility, suggestibility, temporary remissions and a fluctuating course) [7] are common clinical features also of organic tics. This may be why specific diagnostic criteria for functional tics have never been identified [8], with the two most commonly used diagnostic schemes for FMDs, the Fahn Williams criteria [9] and their revised version proposed by Gupta and Lang [10], do not provide any specific advice for functional tics as they do for other FMDs such as tremor, dystonia and myoclonus. As another example of this problem, Thomas and Jankovic’s [11] suggested indicators of FMDs (abrupt onset with maximal disability soon or immediately after onset,

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response to placebo or suggestion, selective disability, dramatic resolution, increase with attention and cessation with distraction) do not seem likely to be able to help in differentiating organic from functional tics. In addition it might not be easy to distinguish functional tics from organic tics because they can coexist in the same patient, as has previously been described [3–5]. Recently, Baizabal-Carvallo et al. [12] studied nine patients with functional tics and found that lack of premonitory sensations, adult onset, absent family history of tics, inability to suppress the movements and coexistence with other FMDs or dissociative nonepileptic attacks were common in their patients. Here a case series is reported including patients with documented functional tics, and their clinical characteristics, risk factors and psychiatric comorbidity are described. Clinical tips are also suggested and video-based examples are provided which might help differential diagnosis in clinical practice.

All the patients diagnosed with functional tics between January 2011 and October 2013 in the movement disorders clinic and in the Tourette clinic of the National Hospital for Neurology and Neurosurgery, London, were reviewed. In our analysis, only cases with a documented or clinically established diagnosis of functional tics, according to the expertise of a consultant neurologist (M.J.E.) who has specific interest in FMDs and in tic disorders, are included. Communication of the diagnosis of functional tics was delivered following the recommendations of Stone and Edwards [13]. The diagnosis was communicated using the term functional tics, explaining to the patient that his/her symptoms, although clearly real, not imagined or ‘all in the mind’, are not caused by any structural damage to the brain. It is explained that they are positively different from organic tics and these differences are shown to them. Demonstration of the physical signs are used as a way of explaining not only how they might be produced (via attentional mechanisms for example), but also how they might get better. For all patients, clinical data were collected and for some of them a video showing the phenomenology was recorded (patient numbers 1, 3, 11). Patients gave their written informed consent for videotaping and for publishing the videos.

onset was 37.2 years (range 16–65 years; SD 13.5). Three patients (27.3%) were female. The onset was abrupt in all patients; tics reached their maximum severity within a few days to months from onset. No patient had family or childhood history of Gilles de la Tourette syndrome (GTS) or another tic disorder. In 10 patients, a clear precipitating event preceded the onset of functional tics. For seven patients the precipitating factor was a physical event (back injury, acupuncture session for irritable bowel syndrome, flu-like symptoms, adrenal failure, pneumonia, back pain, gastroenteritis); one patient reported significant psychological stress at the time of tic onset (stressful time at work); and two patients described a combination of physical and psychological factors. In the remaining one patient no specific precipitating event was identified. Four patients presented functional tics which were stereotyped in nature and no patient reported a waxing and waning course of the movements. Functional tics were reported to be associated with premonitory urges by only two patients. The ability to voluntarily suppress functional tics was observed in two patients. In all patients functional tics were clearly distractible and suggestible during the examination. None of our patients presented pali-, echo- and copro-phenomena. In four patients functional tics interfered with normal action execution akin to ‘blocking tics’. Three patients had movements involving the head and two of them had eye blinking. Eight patients had other functional symptoms (motor, sensory, non-epileptic seizures) in addition to tics. Psychiatric comorbidity was present in eight patients: anxiety was diagnosed in three of them and depression in five. Regarding pharmacological treatment, two patients had previously tried commonly used anti-tic medications for their functional tics, without any benefit; none of them had tried a psychological approach to treatment such as cognitive behavioural therapy. The treatment plan suggested at the time of the visit consisted of cognitive behavioural therapy for three patients (those who did not have comorbidity with other functional neurological symptoms) and five patients were referred to a multidisciplinary inpatient programme for functional neurological symptoms [14]. The remaining three patients were referred to a physical rehabilitation programme [15]. Follow-up for all the patients is still ongoing.

Results

Discussion

Eleven patients diagnosed with functional tics were included in the study. Demographic and clinical characteristics are summarized in Table 1. Mean age at

Given the scarcity of data regarding clinical characteristics, risk factors, psychiatric comorbidity, treatment, prognosis and clinical similarities with their organic

Patients and methods

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counterpart, functional tics pose a difficulty from both a diagnostic and a management point of view. Here 11 cases of functional tics are discussed in the context of the limited data available in the literature. Hints to aid their clinical distinction are proposed (Tables 2 and 3) and illustrative video sequences are provided. Epidemiology of functional tics

Data regarding the prevalence of functional tics in adults are scarce. In one of the largest reported series [6], functional tics accounted for only 2% of FMDs. On the other hand, Mejia and Jankovic [16], who studied the aetiology of secondary tics in a population of 155 patients, reported that 10.3% of them were affected by functional tics. Even though a larger number of studies have been conducted on children and adolescents, data are still limited. According to Isaacs et al. [17], functional tics represent 35% of FMDs in a population of patients from 6 to 20 years old; Ahmed et al. [18] observed a similar prevalence (36.3%) of functional tics in their cohort of patients affected by FMDs between 6 and 15 years old. In contrast, none of the 15 patients (age 7–16 years old) affected by FMDs studied by Schwingenschuh et al. [19] presented functional tics. The discrepancy in the prevalence of functional tics between the different groups might be due to several factors. The first factor is the relatively small size of the samples analysed, and the second the presence of selection bias. There are no studies assessing the prevalence of functional tics in the general population; studies published so far have analysed populations of patients either with tics or with FMDs. Thirdly, as Sampaio and Hounie [8] have previously argued, none of these studies used specific criteria for the diagnosis of functional tics. The 11 cases reported in this study were seen in a specialist quaternary movement disorders clinic over the past 3 years in which approximately 250 patients with FMDs are seen per year. This would support the view that functional tics are rare. However, a populationbased study would be the only way to assess the exact incidence of functional tics. Clinical characteristics of functional tics

All patients included in this case series had an onset of functional tics in adult life, in contrast to the organic counterpart. However, it is difficult to comment on this as a clear distinguishing factor as paediatric patients were not included and the results can therefore be biased. Another explanation (though speculative) is that functional tics, in common with

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other FMDs in childhood, have generally a good prognosis and they are not seen in adult movement disorders clinics. Phenomenologically both functional and organic tics share common features. However, here certain characteristics have been identified which could aid diagnostic distinction. Organic tic disorders commonly start during childhood. The Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-5), classification of tic disorders does not include a category for primary tic disorders that develop during adulthood, other than tic disorder ‘not otherwise specified’. Indeed, childhood/teenage onset is a defining feature of GTS, a chronic disorder of severe motor and vocal tics that manifests before the age of 18 according to the DSM-5 criteria [20]. Tic disorders experienced during adulthood are largely considered to be persistent tics from childhood, and when patients report a late onset it is often assumed that these patients cannot remember having experienced or have not been aware of childhood tics [21,22]. In these cases, reports from relatives in the family are useful. Tics newly presenting during adulthood are rare and they occur mostly in the context of secondary tic disorders (such as Huntington’s disease or neuroacanthocytosis, drug abuse or neuroleptic exposure) [23]. Detailed clinical history, the presence of additional clinical signs on examination and abnormal tests help to reach the correct diagnosis in these cases. Organic tic disorders have a waxing and waning course, with tic characteristics fluctuating and old repertoires being replaced by new ones. They also generally have a stereotyped nature. In our series, none of the patients had functional tics with a waxing and waning course and in only a minority were functional tics stereotyped in nature. Organic tics are often preceded by an internal feeling or sensation known as the ‘premonitory urge’. The urge that precedes the tics is felt to be involuntary and often the driving force for the tic to occur. Most systematic studies suggest that premonitory urge prevalence rates are 77% in patients with GTS who are older than 13 years and up to 100% in older individuals [24,25]. However, only two patients reported an urge prior to their functional tics in our study. Organic tics are often temporarily suppressible, sometimes for minutes, occasionally for hours [26]. Tic suppression typically causes a ‘build-up’ of tics that is then discharged in flurries. In our series, most patients were not able to suppress their functional tics when they were explicitly asked, suggesting that this could be a clue also for the differential diagnosis. This is in line with Baizabal-Carvallo et al.’s findings [12]

51

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42

43

36

38

19

61

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3a

4

5

6

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9

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11a

51

16

35

20

40

40

42

29

65

35

36

F

F

M

M

M

F

M

M

M

M

M

Sex

Video-recorded patients.

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a

Age

Case number

Age at onset of functional tics

Abrupt

Abrupt

Abrupt

Abrupt

Abrupt

Abrupt

Abrupt

Abrupt

Abrupt

Abrupt

Abrupt

Modality of onset

Rapid movements of the arms, legs and axial muscles, vocalizations

Rapid movements of the arms, legs and axial muscles, vocalizations

Abnormal jerky movements of the arms, trunk, shoulder and neck Rapid movements of the neck and arms

Jerks of the neck

Eye blinking, vocalizations

Eye closure with vocalization and bilateral arm elevation Rapid jerking or twisting of the neck, slow raising of the right arm, vocalizations (noises or words) Jerks of all the body, vocalizations

Rapid twitching movements involving the neck, arms and legs Tongue protrusion, vocalizations, uncontrollable laughter

Functional tic description

No

No

No

No

Yes

No

No

No

Yes

No

No

Yes

No

No

No

Yes

No

No

Yes

Yes

No

Urge

Yes

Stereotyped nature

Table 1 Demographic and clinical characteristics of patients

Yes

Yes

Yes

Yes

Yes

Yes

Yes

Yes

Yes

Yes

Yes

Suggestibility

No

Yes

Yes

Yes

Yes

Yes

Yes

Yes

Yes

Yes

Yes

Distractibility

Yes

No

No

Yes

No

No

No

Yes

No

No

No

Ability to suppress functional tics

No

No

No

No

No

No

No

No

No

No

No

Wax and wane course

No

No

Weakness

Non-epileptic seizures (EEG confirmed)

Tremor

Recurrent episodes of functional paralysis Pain Sensory symptoms (electric sensation shooting up and down his neck) Tremor Gait (‘walking on ice’ type problem) Tremor Gait

No

Gait (‘walking on ice’ type problem)

Other functional neurological symptoms

No

No

No

No

No

Yes

No

No

No

Yes

No

Yes

No

No

No

Yes

Yes

Yes

Blocking tics

No

No

No

No

Presence of echo phenomena

Stressful time at work

Lower back pain for which he underwent a lumbar discectomy Gastroenteritis

Adrenal failure after treatment for Pseudomonas Minor road accident Stressful time (she was working very hard at three different jobs) Admission to hospital for pneumonia, respiratory failure and malignant hypertension No

Back injury

Shoulder injury Conflicts with his three brothers Acupuncture session for irritable bowel syndrome Flu-like symptoms

Precipitating event

No

No

Depression

No (risperidone up to 4 mg, no side effects) Not tried

Not tried

Not tried

Not tried

Anxiety

Depression

Not tried

Not tried

Anxiety

Depression

No (sulpiride up to 100 mg, no side effects)

Anxiety

Not tried

Not tried

Depression

Depression

Not tried

No

Psychiatric comorbidity

Response to medications for organic tics

Habit reversal therapy

Habit reversal therapy

Physical rehabilitation programme

Physical rehabilitation programme

Multidisciplinary inpatient programme

Multidisciplinary inpatient programme Multidisciplinary inpatient programme

Multidisciplinary inpatient programme Physical rehabilitation programme

Multidisciplinary inpatient programme Habit reversal therapy

Treatment suggested at the time of the visit

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Table 2 Diagnostic features of organic and functional tics

Age at onset Family history of tic disorders Precipitating events Stereotyped nature Wax and wane course Urge Ability to suppress tics Pali-, echo- and copro-phenomena Blocking tics Localization

Other functional neurological symptoms Psychiatric comorbidity

Response to anti-tic medications

Organic tics

Functional tics

Childhood Yes

Adulthood No

No Yes Yes Yes Yes Yes

Yes Occasionally No No No No

Rarely More commonly head No

Frequently Less commonly head

ADHD, learning disabilities, OCD Yes

Yes Depression, anxiety

No

Table 3 Clues suggesting functional aetiology of tics Historical

General examination

Age at onset is typically in adulthood The onset is abrupt (symptoms often maximal at that time) The course of the symptoms is static The onset of tics is preceded by a precipitating event, which might be both a psychological and a physical one Comorbidity with mood and anxiety disorders Tics do not respond to anti-tic medications Presence of other functional neurological symptoms (psychogenic non-epileptic seizures, functional weakness or other functional movement disorders such as tremor or dystonia) Tics are commonly distributed to trunk, arms and legs but rarely to the head Tics are distractible and suggestible Tics are not associated with premonitory urge and are not voluntarily suppressible Tics interfere with normal action execution akin to ‘blocking tics’ Pali-, echo- and copro-phenomena are not observed

in their series. Explicit attention to the abnormal movement is known to be a key feature for FMDs to occur. Therefore, it seems reasonable that these patients experience difficulties in suppressing functional tics, as they are explicitly instructed to think about the symptom. In addition, tic suggestibility (which refers to the fact that talking about tics makes

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them happen) [27] was present in all of our patients; nevertheless this is a typical feature also of organic tics and may not be helpful in the differential diagnosis. Further, organic tics rarely lead to the disruption of an ongoing action or interfere with communication. In cases where this disruption is significant, these tics have been labeled blocking [21]. Interestingly, more than half of our patients had this phenomenon. Tic distribution is another interesting aspect. Organic tics usually start in the face and tend to extend caudally, with a remaining preference for head, eyes, neck, shoulders and arms [13,26]. In our patients with functional tics, tic distribution differs: only three patients had movements involving the head and only two of them had eye blinking, which is one of the most common tics in GTS [28]. Finally, although pali, echo- and copro-phenomena are seen in GTS, they were not present in any of our patients. Interestingly, most of our patients reported a precipitating factor preceding the onset of the functional tics. It has been widely described in the literature how FMDs can be triggered by psychological [29] or physical [30,31] precipitating events. Also organic tic disorders may be triggered by physical or emotional precipitating events but this happens significantly less commonly (30% of cases) [26]. Finally, patients with primary tic disorders often have a concomitant psychiatric diagnosis such as obsessive-compulsive disorder (OCD) (25%–40% of patients), attention-deficit/hyperactivity disorder (ADHD) (about 50% of patients) or learning disabilities (25%–30% of patients) [26]. In our series none of the patients suffered from OCD or ADHD, but all of them had anxiety or depression. Seven of our patients presented additional functional neurological symptoms (motor, sensation or non-epileptic seizures), which might help with the diagnosis. However, clinicians should be cautious about relying specifically on this aspect as functional overlay in patients with typical neurological disorders is not uncommon. Finally, none of the patients who were treated with anti-tic medications (such as sulpiride and risperidone) experienced a clinical improvement of their functional tics. Some of the clinical features typical of functional tics discussed in this paper (such as the lack of premonitory sensations, the inability to suppress the movements and the coexistence with other FMDs and non-epileptic seizures) have been recently highlighted also by Baizabal-Carvallo et al. [12]. With our case series, some additional features such as tic distribution and phenomenology, the common presence of interfer-

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ence between tics and voluntary actions, and the absence of pali-, echo- and copro-phenomena have been added, which it is hoped will help clinicians to distinguish functional tics from their organic counterparts. In our sample, unlike Baizabal-Carvallo et al., it was found that functional tics were more prevalent in males. Several limitations to our study are acknowledged. First, the sample size is very small and therefore this case series should be interpreted with caution. However, our main aim was to highlight the clinical difficulties for the specific diagnosis of functional tics and suggest initial features to define further research. Secondly, as a retrospective case series, our study relied on recall of patients and accuracy of written records and therefore some clinical data and information may be missing. Thirdly, no electrophysiological investigations were used. The Bereitschaftspotential, which represents a cortical activation preceding self-initiated movements [32], might be helpful in the differential diagnosis between functional and organic tics, although there are reports of the presence of a Bereitschaftspotential prior to organic tics. Indeed, it is important to underline, as also suggested in a recent study [33], that the most valuable element to make a correct diagnosis of functional tics remains the clinical assessment including both the patient’s history and the clinical examination. Finally there was no control group of patients with organic tics. Future studies could directly compare populations with functional and organic tics which may provide additional information for determining which clinical features best discriminate between the two groups.

was funded by an EFNS scientific fellowship last year. Dr Christos Ganos receives academic research support by the Deutsche Forschungsgemeinschaft (GA2031/11) and has also received travel grants by the Movement Disorders Society, Actelion, Ipsen. Professor Kailash P. Bhatia: Funding for travel from GlaxoSmithKline, Orion Corporation, Ipsen and Merz Pharmaceuticals LLC; serves on the editorial boards of Movement Disorders and Therapeutic Advances in Neurological Disorders; receives royalties from the publication of Oxford Specialist Handbook of Parkinson’s Disease and Other Movement Disorders (Oxford University Press, 2008); received speaker honoraria from GlaxoSmithKline, Ipsen, Merz Pharmaceuticals LLC and Sun Pharmaceutical Industries Ltd; personal compensation for scientific advisory board for GSK and Boehringer Ingelheim; received research support from Ipsen and from the Halley Stewart Trust through Dystonia Society UK, and the Wellcome Trust MRC strategic neurodegenerative disease initiative award (Ref. number WT089698), a grant from the Dystonia Coalition and a grant from Parkinson’s UK (Ref. number G-10). Dr Mark Edwards is funded by a fellowship awarded by the National Institute for Health Research and is supported by researchers at the National Institute for Health Research University College London Hospitals Biomedical Research Centre. He receives grant support from Parkinson’s UK, the UK Dystonia Society, Bachmann Strauss Foundation. He has received honoraria for speaking from the International Movement Disorders Society and UCB Pharma.

Supporting Information Conclusions Our data suggest that functional tics might be differentiated from organic tics by particular clinical phenomena. However, it is important to note that none of these features is entirely specific and further studies on larger populations of patients are needed to delineate precise diagnostic criteria for functional tics. This will be of undoubtable value in helping clinicians from a diagnostic, prognostic and therapeutic point of view.

Acknowledgement The study has not been funded by any institution.

Disclosure of conflicts of interest Dr Benedetta Demartini and Dr Lucia Ricciardi have no conflicts of interest to declare. Dr Isabel Parees

Additional Supporting Information may be found in the online version of this article: Video S1. Patient 1. Video S2. Patient 3. Video S3. Patient 11.

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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 ...
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