Demographics

In our cohort of 159 patients of FMDs, CFMDs were present in 26 patients (16.35%). The majority of our CFMDs patients were females (16; 61.53%) and their mean ± [SD] age was 33.96 ± [16.94] years (range 11 to 83 years). There were 5 children (age of onset <18 years) and 3 elderly (age of onset >60 years) patients in our cohort. The duration of illness ranged from one day to 6 years (mean± SD: 402.03 ±534.97 days).

Clinical features

Of the 26 patients diagnosed with CFMDs, 24 (92.30%) met the Fahn-Williams diagnostic criteria for the documented, and 2 (7.69%) for the clinically established. We have provided the videos of 9 patients highlighting the wide spectrum of phenomenology in our CFMDs cohort (See video). The onset of illness was abrupt in 26.92% (7/26) and gradual in 73.07% (19/26) of patients. Most of the patients had symptoms pertaining to either one half or the whole of the face with the majority having orofacial dyskinesias (n = 5; 19.23%) and hemifacial spasm (n = 4; 15.38%). Out of the 5 cases of orofacial dyskinesias, 3 were men and 2 were women. All the patients with hemifacial spasm were females and as compared to organic hemifacial spasm, it was seen to be fixed instead of clonic in Case 1 and inconsistent in their location (alternating from side to side) in Case 2 (See videos). Amongst the 4 (15.38%) cases with movements in and around the eyes, we had one case each of bilateral eye ptosis (Case 4: See video), blepharospasm, bilateral ‘painful’ eyelid myoclonus and eyebrow dyskinesia in the form of repetitive frontalis ‘overactivity’. The tongue involvement was seen in 4 patients (15.38%) in the form of dystonia (n = 3) and tremor (n = 1), and 3 of them were females. We came across several unusual phenomenologies including bruxism, chin tremor, mouth-opening dystonia, oromandibular dyskinesia, and jaw spasm each in one patient. Case 7 (See video) was that of a young female with a palatal tremor that disappeared on using a tongue depressor. There were 2 cases of functional speech and voice disorders both of which were abrupt in onset: a male with stuttering voice (Case 9: See video) and one female with childlike prosody along with left-sided functional hemiparesis with numbness (Case 10). Six of the 26 (23.07%) patients also had additional craniofacial movements along with the primary movement disorder.

Distractibility, variability, and entrainment

Clinical incongruency and inconsistency are the hallmarks of the FMDs and are necessary for the diagnosis to be certain. Seventeen (65.38%) of our patients had variability in their symptoms, 10 (38.46%) had distractibility and 3 (11.53%) had entrainment.

Additional extracranial movements

Ten (38.46%) of our patients also had concomitant functional movements involving the body regions other than the craniofacial areas and what is remarkable is that 9 (90%) of them were related to the shoulder and upper limbs: 2 cases had bilateral shoulder-shrugging movements, 4 cases had bilateral upper limb tremors, one had twisting movements of upper limbs, one had writing difficulty for 10 days, and one patient also had left-sided hemiparesis with numbness of the same regions [Hoover’s sign was positive] with acute speech disturbance. Lower limb tremors and functional neck dystonia were present in one patient each.

Precipitating factors

Twenty-two (84.61%) out of 26 of our patients had a well-defined stressor for these abnormal movements. Family conflicts and emotional stress were the most common precipitating factors present in 30.76% (n = 8) of patients and interestingly, all cases with these stressors were females. In male patients, stress related to financial constraints was the most common precipitating factor. Two of the patients had physical inciting factors such as gastric upset and road traffic accidents. The children and young adults mostly had factors related to school stress and feelings of anxiety and social stress.

Associated illnesses

Nine of our patients had associated illnesses and 5 of them had neuropsychiatric issues in the form of anxiety and depression and 4 patients had associated headaches. Organic illnesses in the form of subdural hematoma, cervical dystonia, seizure disorder, and intracranial space-occupying lesion were present in 4 patients that couldn’t be attributable to the movement disorder the case presented with.

Outcome

At the 3-months follow-up, 9 (34.61%) out of 26 patients had improved whereas 4 (15.38%) of them failed to show any improvement whatsoever. The overwhelming majority of the patients (13/26; 50%) had only partial recovery of their symptoms with a variable course.

Summary of the cranial functional movement disorders cases reported in the literature

Out of 311 articles that we retrieved for our systematic review, 25 were found to be relevant (Figure 1; supplementary online table [7, 8, 9, 11, 12, 13, 14, 17, 20, 21, 26, 27, 28, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48]. Of the total number of 434 patients in all these studies, 191 (44%) were females and 48 (11%) were males. For the remaining 195 (44.93%) patients, gender was not specified. The majority of the patients were found to have some form of facial or eye involvement. The movement related to eyes was mostly unspecified (n = 188) with others being that of blepharospasm (n = 3) and pseudoptosis (n = 1). Out of all the abnormal facial movements, pure hemifacial spasm (37/152; 24.34%), and facial dystonia (17/152; 11.18%) were the most common. Other involved regions were jaw (n = 119), speech and voice (n = 107), platysma (n = 89), tongue (n = 79), palatal or lip (n = 33) and head (n = 10). The phenomenologies of 12 patients were not specified in the respective studies. For a total of 434 patients, 793 phenomenologies were described which translates into the fact that most of these patients had multiple functional movements involving various parts of the body. Clearly mentioned overlaps were observed in about 60 (16%) of 375 patients. The detailed phenomenologies of patients with overlaps were reported by Factor et al [11] [head tremor with eyelid fluttering (n = 1), blepharospasm with dysphonia (n = 1), and head tremor with intermittent tongue protrusion (n = 1)], Chung et al [12] [(speech abnormality with some facial abnormal movement (n = 5)], Kamble et al [13] [abnormal head movements + tremors (n = 2), mutism + gait abnormality (n = 2), facial dystonia + mutism (n = 2), palatal myoclonus + astasia abasia + facial dystonia (n = 1) and facial dystonia + tremors (n = 2)] and Stone et al [14] [one case with right “pseudoptosis” with contraction of orbicularis oculis and oris which gave an impression of right facial weakness with unilateral photophobia in the right eye]. In a study of the 101 patients with functional abnormalities, Teodoro et al reported that effortful facial expression and other responses (e.g. frowning, grimacing, effortful breathing) in 26.7% of patients and/or excessive blinking in 38.6% of patients predominated, with at least one of them being present in 40.6% (41/101) patients [15].

Eyes

Ocular or peri-ocular movements seem to be common when it comes to FMDs as is evident from two other case series (Fasano et al with 51% patients out of 61 cases and Stone et al with 90% patients out of 41 cases) with a large number of cases with at least some form of eye involvement [7, 8]. We had 4 patients who had abnormal movements related to the eyes: one patient each of bilateral ptosis, blepharospasm, eyebrow dyskinesia, and bilateral ‘painful’ eyelid myoclonus. In a large series of 101 patients clinical examination triggered facial and eye movement disorders in 46% of patients, but, this phenomenon was not observed in any of our patients [15]. In the same vein, Stone et al in 2010 reported a case with recurrent episodes of right “pseudoptosis” with contraction of orbicularis oculis and oris which gave an impression of right facial weakness with unilateral photophobia in the right eye [14]. Our patients did not have any concomitant facial abnormal movements. Convergence spasm has been previously reported as the most frequent functional eye movement disorder and it was seen in as many as 69% of FMDs cases in a study reporting 13 patients [9, 16]. However, we did not come across any patient with convergence spasm.

Face

Out of our 26 patients, 10 of them had varied facial involvement among which 5 had orofacial dyskinesias, 4 were that of hemifacial spasm and one patient had pure facial dyskinesia. In 2001, Tan et al reported 5 patients (all females) and in 2016, Baizabal-Carvallo et al reported 15 patients with facial movement [17, 18]. Consistent with the literature, all our 4 hemifacial spasm patients were females. The onset of the movements was gradual in all of them barring one in whom the onset was abrupt. The clues to psychogenicity in these patients were movements mostly involved in the lower half of the face, were variable and distractible. In one case it was seen to be fixed instead of clonic and in another movement were inconsistent in their location (alternating from side to side) [4]. None of our patients reported facial spasms during sleep (said to be present in up to 80% of organic hemifacial spasm or any worsening of spasms during voluntary facial contractions (seen in up to 39% of hemifacial spasm patients); most patients had lower-face involvement at onset in contrast to the isolated lid involvement typically present at the onset in organic hemifacial spasm [19].

Stomatognathic system: jaws, lips, tongue, teeth, and associated soft tissues

Several case series have shown the very relevant involvement of this system when it comes to facial functional movement disorders (FFMDs) [7, 8]. The most common phenotype is tonic jaw deviation accompanying ipsilateral downward and lateral lip pulling, seen in 84.3% of patients with FFMDs involving the craniofacial region but we did not have any such patient in our series which perhaps highlights the varied presentations of FMDs in different geographic areas [7]. Yoshida et al in their very recent study, recorded 58 patients with FMDs in the stomatognathic system in which functional dystonia phenotype was observed in 44.8% and 27.6% of their patients showed very fast repeated jaw and/or lingual movements and 72.4% of their cases were females [20]. This data is similar to our study in which 77.7% (7/9) patients were women. What is significant and should be noted is that 50% of the cases of the Yoshida et al study reported pain whereas none of our patients reported it [20]. Also, none of our patients had precipitating factors such as dental (44.8%) or physical trauma (12.1%) that were the commonest causes seen in the study published by Yoshida et al [20]. Whereas abnormal jaw and tongue movements have been earlier reported in various case series, none of them describing bruxism as our study has [7, 8, 20]. Functional palatal and lip tremors have been reported but functional chin tremor is rare and we report one such case (Case 5; see video) [20, 21]. We also report one young girl (Case 7; see video) with a psychogenic palatal tremor that was accompanied by bilateral ear clicking. Biller et al in 2013 proposed to segregate essential palatal tremor into 3 clinical overlapping variants: psychogenic, un-voluntary or secondary essential, and voluntary essential palatal tremor [22]. Also, as per the literature, the female gender and the presence of bilateral ear clicking in our patient is consistent with psychogenicity [23]. Our patient did not have acute upper respiratory tract infection as a precipitating factor as reported in other studies [21, 24]. Platysma overactivity has been commonly reported previously to co-exist with FFMDs (61% in Fasano et al, 85% in Stone et al) but only 7.6% (2/26) of our patients were found to have it [7, 8].

Speech

Various studies have reported that between 16.5% and 53% of FMDs patients have a comorbid functional abnormality in speech or voice [11, 25, 26, 27, 28]. While dysphonia, stuttering, and prosodic abnormalities are common among functional voice and speech disorders (FSVDs), it is important to realize that any aspect of speech or phonation may be affected [12]. Acquired organic stuttering often presents with dysarthria, aphasia, or apraxia of speech; the absence of these features is a red flag for a functional etiology [12]. One female in our cohort had abrupt onset functional hemiparesis with concomitant functional child-like prosody and 3 out of the 6 cases reported by Chung et al who had prosodic disturbances were females as well [12]. We report one male patient (Case 9: See video) with functional stuttering (FS) and this is consistent with the literature that says that FS is equally prevalent among males and females, contrasting with the 3:1 male: female ratio observed in patients with organic stuttering [29]. In contrast with organic motor speech disorders (OMSDs), patients with FSVDs often exhibit inconsistencies and considerable variability in their speech or phonation and their symptoms may alter considerably with distraction or suggestibility [30]. Patients with FSVDs may also exhibit struggle behaviour resulting in exaggerated facial movements, including marked facial grimacing, lip pursing, eye blinking or contraction of the periorbital, lower facial muscles, or platysma during an attempted speech [12]. Patients complaining of weakness may paradoxically exhibit speech with a strained quality or exaggerated facial posturing that is inconsistent with their complaint of weakness [31]. Also, the course of FSVDs can be highly variable and in one conversation many qualitative changes in the character of the dysphonia or severity of the symptoms can occur and symptom reversibility is one of the most important clinical features of FSVDs [32]. It is crucial to diagnose these disorders as deficits in patients with FSVDs also have a greater potential for reversibility than those in OMSDs patients and while speech therapy rarely provides improvement for patients with OMSDs, various studies have documented that a course of speech therapy can be quite effective for many patients with FSVDs [12, 33].

Extra-craniofacial psychogenic movements

The co-occurrence of different functional disorders is well known [34]. 38.46% (10/26) of our patients had concomitant functional movements involving the body regions other than the craniofacial areas and 90% (9/10) of them were related to the shoulder and upper limbs. This seems to be consistent with the literature as extra-facial contractions involved upper limb in 30% of the 61 patients in the series by Fasano et al and 78% patients out of the 41 cases evaluated by Stone et al had evidence of functional limb weakness and 22% had limb dystonia [7, 8].

Precipitating factors

Since the advent of modern psychiatry, a correlation between the experience of emotional trauma and psychogenic symptoms has been postulated [35]. Kletenik et al pointed out that trauma and adverse life events are important risk factors for developing FMDs and they have also reported that the higher prevalence of FMDs in women is likely related to both higher rates of sexual abuse against women and the impact of sexual abuse in women [36]. But in our Indian society, there seems to be a significant impact of culture, ethnicities, and other psychosocial variations on the precipitating factors. We differ from the western literature when it comes to precipitating factors for FMDs as, in our country, even today, there are germane concerns regarding a lack of proper communication between the physician and the patient, especially women, who do not usually come out with complaints of sexual abuse or marital conflicts to avoid running the risk of social embarrassment. Seven out of sixteen women (43.75%) in our study, however, did cite familial disharmony on careful probing and three of them reported financial difficulties. 5 out of 10 men (50%) had been facing financial constraints and work-related stress, whereas, in children, family separation, school-related performance pressure, tiffs with friends, and absence of a sibling were common propellants in our study. Physical stressors seem to be relatively less common with one case with a prior history of a road traffic accident and one with a preceding bout of severe gastric upset. Two of our patients had interesting risk factors with one case developing the FMD after an episode of claustrophobia and one case who developed tongue tremor while keenly observing himself in the mirror during shaving.

Associated illnesses

Eleven out of twenty-six (42.30%) of our patients had some form of associated illness. Four of them reported headaches (4/26; 15.38%) which is similar to the study conducted by Stone et al in which migraine triggered functional facial movement disorders in 17% of the patients [8] Neuropsychiatric disturbances ruled the roost with seven (26.92%; 7/26) of our patients reporting it either in the form of anxiety, depression, feelings of loneliness and isolation with one of them not being specified. Depression and headache were also common in the series by Fasano et al [7]. Other organic clinical entities that were found to co-exist in 15.38% (4/26) patients. Examples include subdural hematoma, organic cervical dystonia, seizure disorder, and an intracranial mass was found in one patient each and this observation is important as it emphasizes the fact that quite often organic and functional pathologies can overlap and that the presence of an organic pathology does not rule out a functional element or vice versa.

Outcome

Little is known about the course and the outcome in CFMDs patients. At the end of three months, 34.61% of our patients had improved with no relapses, 15.38% did not show any improvement and an overwhelming majority of 50% patients showed partial improvement only with a variable course. In the study reported by Fasano et al, the course was stable in 53%, variable in 33%, and had diurnal fluctuations in one-fifth.

Certain limitations should be kept in mind before the interpretation of the results of our study. The major limitation was represented by its retrospective chart review design, which has certain inherent errors such as missing data, recall bias, and follow-up details. Further, our patients did not follow a standard protocol-based treatment which may have affected the outcome. There were some inadvertent limitations in the systematic literature review also which was markedly affected by the incomplete data provided in various studies. We were not able to figure out the genders of a huge majority of cases and phenomenologies of all the patients could not be well delineated as many authors presented their data in the form of percentages only and we could only roughly calculate the probable patient number [7, 8].

Despite all these limitations, our study has reported some important observations regarding CFMDs patients. First, females were more likely to have CFMDs similar to other FMDs and facial involvement was more likely to occur than other cranial musculatures. Second, we have reported some unusual phenomenologies like chin tremor, ptosis, eyebrow dyskinesia, and bruxism. Third, functional movements involving the body regions other than the craniofacial areas were present in one third (38.46%) of our patients and 90% of them were related to the shoulder and upper limbs. Fourth, precipitating factors were present in 84.61% of the patients and associated illnesses were present in 42.30% of the patients. The most common precipitating factors in females were emotional and familial stress, whereas financial stress was the most common in males. Fifth, one-third of our patients had a good outcome, whereas half of the patients had a variable course.