Globus Pallidum DBS for Task-Specific Dystonia in a Professional Golfer.

Dear Editor

Task-specific dystonias are focal dystonias presenting in body parts engaged in highly skilled or overlearned tasks involving repetitive actions and overuse of muscles. These tasks commonly include playing musical instruments, writing, typing, and sports.1 Although the neck is the most frequent body region involved in focal dystonia, task-specific cervical dystonia has only been rarely reported in literature.2 These case reports were observed to be in relation to frequent cradling of a phone to the right ear (muscles engaged in tilting of neck involved),2 chronic sledgehammer use (shoulder muscles),3 chronic heavy lifting (shoulder muscles),3 and in one report the patient had bilateral arm amputation and used the mouth for holding and the neck for stabilizing during many motor activities.4 These patients were treated with botulinum toxin injections, with only two of them reporting mild to moderate improvement. We describe task-specific dystonia symptoms (predominantly cervical) in a professional golfer who quit his career due to disabling symptoms but improved remarkably with deep brain stimulation (DBS) therapy.

A 56-year-old right-handed professional male golfer presented with a 10-year history of gradually progressive rightward and upward involuntary turning of the head noted during the swinging task along with intermittent left arm cramping during the putting task. He reported playing golf for over 35 years. He stated his neck symptoms were the most bothersome and the arm symptoms were very mild. He denied the presence of sensory trick for alleviation of his symptoms. He also complained of occasional tilting of the head to the left while playing golf. He reported he had no involuntary neck movement when the neck muscles were engaged in other tasks such as driving, watching television, or during routine conversation (non-golf activities). During the physical examination, a slight prominence of the left sternocleidomastoid muscle was noted and abnormal right turning of head (torticollis) was elicited specific to the swinging task employed during golf (Video 1). There was no abnormal posturing noted in the head or any other body part during rest, posture, and action tasks such as voluntary neck flexion, neck extension, side-to-side movement, and the finger-to-nose task for the arms. He underwent multiple medication trials including baclofen, tizanidine, clonazepam, and trihexyphenidyl. He was then treated with several rounds of onabotulinum toxin injections administered into the left sternocleidomastoid, right splenius capitis, right semispinalis capitis, and bilateral trapezius muscles (maximum dose 300 units). However, none of these treatments could alleviate his symptoms. Given the persistence of disabling symptoms manifesting only during golf, he eventually quit playing competitive tournaments (PGA tournaments). Subsequently, based on the recommendations of an interdisciplinary team evaluation, he underwent bilateral globus pallidus internus (GPi) DBS surgery. DBS leads were stereotactically implanted in the ventroposterolateral GPi and were localized with magnetic resonance imaging (MRI) and microelectrode mapping. A quadripolar electrode (Model 3387; Medtronic, MN) with four contacts numbered 0 (ventral) to 3 (dorsal) for the left side and four contacts numbered 8 (ventral) to 11 (dorsal) for the right side was implanted. The lead location was confirmed on a postoperative computed tomography scan fused with the preoperative MRI scan (Figure 1). Three months postoperatively, he reported significant improvement of approximately 50%, which further improved to 85% following 6 months of optimization in programming (Video 1, Segment 2). He has now been followed at our center for over 18 months and he endorses persistent clinical improvement. The current programming settings are for left GPi: C+2–; voltage 2.6; pulse width 60; frequency 180; and for right GPi: C+10–; voltage 2.6; pulse width 60; frequency 180. Using these settings he has resumed playing competitive golf.

Video 1.

Pre and Post DBS Video Illustration. Segment 1. This video illustrates the task-specific cervical dystonia manifested during swinging golf task. Dystonia manifests as sudden turning of head to the right with slight upward movement. Segment 2. This segment illustrates the remarkable improvement reported by the patient in about 6 months after surgery and programming. The patient is now able to resume competitive golf activities.

Figure 1

MRI Targeting and Atlas Mapping for DBS Lead. Deep brain stimulation (DBS) leads were stereotactically implanted in the ventroposterolateral globus pallidus (GPi) and were localized with magnetic resonance imaging (MRI) and microelectrode mapping. A quadripolar electrode (Model 3387; Medtronic, MN) with four contacts numbered 0 (ventral) to 3 (dorsal) for the left side and numbered 8 (ventral) to 11 (dorsal) for the right side was implanted. The GPi lead location on postoperative computed tomography was fused with the preoperative MRI scan and measured using Schaltenbrand–Bailey’s stereotactic atlas. We confirmed a well-placed location for the DBS leads on both sides. The coordinates for the tip of the right lead were X 21.06 mm; Y 0.06 mm; Z –5.09 mm; AC–PC angle 65; centerline angle 7. The coordinates for the tip of the left lead were X 21.25 mm; Y –0.64 mm; Z –3.17 mm; anterior commissure-posterior commissure (AC–PC) angle 65; centerline angle 1. Brain MRI T2 sequence coronal (A), axial (B), and sagittal (C) views of right GPi lead location. Brain MRI T2 sequence coronal (D), axial (E), and sagittal (F) views of left GPi lead location. The red line indicates the lead trajectory. Outlines of the atlas: blue, caudate nucleus; red, globus pallidus internus; lateral green, globus pallidus externus; internal green, thalamus; yellow, optic tract.

The phenomenology and pathophysiology of task-specific dystonia as well as the phenomenon referred to as “yips” in golfers is not completely understood. Yips have been described to be dystonic in origin.5 In a study by Adler et al.,6 co-contraction of wrist flexors and extensors was demonstrated during golf tasks in a large cohort of golfers. Yips in golf traditionally affects only the arm muscles. Our patient had symptoms in the arm muscles and the neck region (predominantly neck). A similar report by Dhungana and Jankovic7 described a golfer who initially had the arm symptoms described in yips who later developed neck turning during swinging. We believe, as golf requires hand–eye coordination with contemporaneous neck coordination especially during the swinging task, it is not surprising that golfers may sometimes develop symptoms in the neck in addition to the arm muscles.

The social and professional impact of task-specific dystonia on the quality-of-life (QOL) in golfers has not been described before. There are several studies that have reported QOL for dystonia in general; however, the impact in task-specific dystonia has not been well studied. In a large analysis of about 1,000 patients with musician’s dystonia, debilitating symptoms for most affected musicians manifested in the fourth decade of life coinciding with the peak of their career.8 These musicians could not return to their prior level of performance despite medications and in some cases multiple trials with botulinum toxin injections.

Our report highlights the role of surgical intervention in task-specific dystonia, which has not been well studied. Few small studies on ventro-oralis thalamotomy in musician’s dystonia and thalamic stimulation in writer’s cramp have demonstrated promising results.1 However there is no study to date on DBS for task-specific cervical dystonia or DBS for yips. The remarkable clinical improvement experienced by our patient is encouraging. Further studies will be needed to confirm the therapeutic potential of DBS in medication-refractory task-specific dystonia. Future tractography studies are also needed to identify the fiber tracts that respond to DBS and are unique to task-specific dystonia to better understand the pathophysiology. This improved understanding in turn will contribute to better therapies for task specific dystonia.