Could motor blocks be a therapeutic option for treatment‐resistant functional dystonia? A case series of three patients

Abstract

The diagnosis of functional dystonia is challenging because it is difficult to distinguish functional dystonia from other types of dystonia. After diagnostic explanation, multidisciplinary care is recommended, but some patients are resistant to treatments. We used motor blocks in three patients with severe resistant functional dystonia of the upper limbs to test (i) whether joint contracture was present and (ii) whether motor blocks have a therapeutic effect on functional dystonia. Patient 1 showed a good and sustained therapeutic response, Patient 2 experienced a resolution of the dystonic posture that lasted for 10 days, and Patient 3 experienced no effect. Motor blocks may be a useful therapeutic option in chronic treatment‐resistant functional dystonia. The treatment effect might be achieved through the experience of normal positioning and functioning of the limb.

INTRODUCTION

The diagnosis of functional dystonia is challenging because it is difficult to distinguish functional dystonia from other types of dystonia [1]. After diagnostic explanation, multidisciplinary care is recommended [2]. However, some patients' symptoms are resistant to treatments. Assessment under sedation may be used in these patients to help them experience transient resolution of their symptoms. The use of anesthetic agents does, however, entail risks [3].

We used motor blocks [4] in three patients with severe resistant functional dystonia of the upper limbs to test (i) whether joint contracture was present and (ii) whether motor blocks have a therapeutic effect on functional dystonia.

The motor block procedure was performed in three consecutive patients after they had given written informed consent. All patients said they fully agreed with the diagnosis of functional neurological disorder (FND). Injection of 1% lidocaine was performed to the median and ulnar nerves located using the anatomical landmarks combined with electrical stimulation guidance at 0.8–1 mA. Follow‐up consultations were conducted 14 days, 3 months and 12 months after the procedure. The Clinical Global Impression—Improvement (CGI‐I) scale was used by the patients to rate the results of the procedure [5]. This scale ranges from 1 to 7 as follows: 1: very much improved; 2: much improved; 3: minimally improved; 4: no change from baseline; 5: minimally worse; 6: much worse; and 7: very much worse. For illustration of the cases, see Figure 1, Table 1 and Videos 1, 2, 3, 4, 5.

FIGURE 1.

Image of the hand (A) before and (B) approximately 3 h after the motor block for Patients 1, 2 and 3.

TABLE 1.

Clinical Global Impression—Improvement scores reported by the three patients at each follow‐up.

Case	Age, years	CGI‐I score on day 1	CGI‐I score on day 14	CGI‐I score at 3 months	CGI‐I score at 12 months
Patient 1	33	1	1	1	1
Patient 2	42	2	3	3	3
Patient 3	25	3	4	4	4

Note: CGI‐I was self‐reported by the patients with scores defined as follows: 1: very much improved; 2: much improved; 3: minimally improved; 4: no change from baseline; 5: minimally worse; 6: much worse; 7: very much worse.

Abbreviation: CGI‐I, Clinical Global Impression—Improvement scale.

VIDEO 1.

Case 1, before: This video of Patient 1 was taken before the procedure. It shows the fixed dystonic posture of the left hand.

VIDEO 2.

Case 1, 2 h after: This video of Patient 1 was taken 2 h after the procedure.

VIDEO 3.

Case 2, before: This video of Patient 2 was taken before the procedure. It shows the fixed dystonic posture of the right hand, a functional tremor appears while Patient 2 is trying to open her right hand.

VIDEO 4.

Case 2, immediately after: This video of Patient 2 was taken just after the procedure. The patient can open and close her hand again, but the underlying soft tissue contracture limits the range of movements.

VIDEO 5.

Case 3, before: This video of Patient 3 was taken before the procedure. It shows the fixed dystonic posture of the left hand. The patient opens her left hand by herself with difficulties. The symptoms remained unchanged after the procedure.

Patient 1

Patient 1 was a woman, aged 33 years, with a functional movement disorder for 7 years (Videos 1, 1). Her symptoms included painful fixed left‐hand dystonia. The patient had a comorbid bipolar disorder and a dissociative identity disorder. She had undergone several treatments, including regular physiotherapy, several hospitalizations in rehabilitation centers, botulinum toxin injections, repeated suprathreshold transcranial magnetic stimulation (TMS) and eye movement desensitization and reprocessing (EMDR).

Procedure

The patient received injection of 8 mL 1% lidocaine next to the median and the ulnar nerves above the elbow.

Effect

Approximately 10 min after the injection, the patient observed a full recovery of finger and hand movement that persisted at day 14. She was still significantly improved at 3‐month and 1‐year follow‐ups, with consistent CGI‐I scores of 1. The patient explained that when she experiences relapses, she recalls the feeling she had after the procedure to help her hand open again.

Patient 2

Patient 2 was a woman, aged 42 years, with functional fixed dystonic posture of the right hand for 4 years (Videos 2, 3). After explanation of the diagnosis, she underwent physiotherapy and suprathreshold TMS, with no effect on dystonia.

Procedure

The patient received injection of 10 mL 1% lidocaine next to the median and ulnar nerves at the proximal third of the arm.

Effect

Immediately after the injection, the patient had a resolution of the dystonic posture which revealed an underlying soft tissue contracture, limiting range of the finger flexors. The patient reported a CGI‐I score after the procedure of 2 and the beneficial effect of the block lasted for 10 days. The patient's CGI‐I score at 1 year follow‐up was 3.

Patient 3

Patient 3 was a woman, aged 25 years, who had had a fixed functional dystonia of the left hand for 6 years that appeared just after a car accident (Video 5). She underwent physiotherapy, TMS, EMDR and has been hospitalized in a rehabilitation center for almost 1 year, with no improvement of symptoms.

Procedure

The patient received injection of 10 mL 1% lidocaine next to the median and the ulnar nerves above the elbow.

Effect

There was only a slight effect just after the procedure that did not last more than 1 h, with no change (CGI‐I score 4) reported at follow‐up.

DISCUSSION

Motor blocks may be a useful therapeutic option in chronic resistant functional dystonia. The beneficial effects of this treatment might be achieved through the experience of normal positioning and functioning of the limb. However, motor blocks should be used with caution as there is only sparse evidence for a potential therapeutic effect, and anesthesia can sometimes also be a precipitating factor for FND [6].

The three patients described in this paper had chronic severe resistant functional dystonia of the hand but reacted differently to the procedure. Patient 1 showed a good and sustained therapeutic response, Patient 2 had an immediate resolution of the dystonic posture that lasted for 10 days, and Patient 3 experienced no effect. The procedure was helpful as it revealed a joint contracture in Patient 2 and demonstrated an efficacy that exceeded the usual duration of effect of motor blocks (30 min approximately) in Patients 1 and 2. Moreover, while the efficacy of the procedure was likely led by the anesthetic agent in Patient 1, the immediate improvement in Patient 2 indicates that efficacy was achieved through suggestion. Finally, the absence of effect in Patient 3 may be due to a lack of precision in electrical guidance, but also raises the possibility that branches of the median and cubital nerves were not impacted by the peripheral block. For this reason, either an increased dose of lidocaine, or proximal blocks, such as axillar or spinal anesthesia, that would lead to a total disruption of motor contractions might be even more relevant as a specific treatment approach in these complex clinical situations. Indeed, inducing complete paralysis through a proximal block may be more effective in helping the patient experience a normalization of movement.

Moreover, various additional factors and comorbidities may have played a role in shaping the response to treatment. Only Patient 1 had significant psychiatric comorbidities, yet surprisingly she experienced the most favorable therapeutic outcome. Additional perpetuating factors such as the ongoing litigation with the insurance company in the case of Patient 3 could also be involved. Furthermore, a lack of diagnostic acceptance could be a significant perpetuating factor. Although all patients reported full agreement with the diagnosis of FND, a potential incongruity might exist between their reported agreement and their deeply ingrained beliefs.

Our findings have important implications for clinical practice since patients with resistant functional dystonia have poor outcomes.

AUTHOR CONTRIBUTIONS

Béatrice Garcin: Conceptualization; investigation; writing – original draft; writing – review and editing; methodology. Amaury Cinquin: Writing – original draft. Bertrand Degos: Investigation; writing – review and editing. Emmanuel Roze: Investigation; writing – review and editing. Alexis Schnitzler: Conceptualization; investigation; methodology; writing – review and editing.

CONFLICT OF INTEREST STATEMENT

The authors report no conflict of interest for this study.

Garcin B, Cinquin A, Degos B, Roze E, Schnitzler A. Could motor blocks be a therapeutic option for treatment‐resistant functional dystonia? A case series of three patients. Eur J Neurol. 2024;31:e16150. doi: 10.1111/ene.16150

DATA AVAILABILITY STATEMENT

The data that support the findings of this study are available from the corresponding author upon reasonable request.