Centromedian-Parafascicular Complex Deep Brain Stimulation for Tourette Syndrome

Abstract

Deep brain stimulation (DBS) of the thalamic centromedian/parafascicular (CM-Pf) complex has been reported as a promising treatment for patients with severe, treatment resistant Tourette syndrome (TS). In this study, safety and clinical outcomes of bilateral thalamic CM-Pf DBS were reviewed in a series of twelve consecutive patients with medically refractory TS, eleven of whom met the criteria of post-surgical follow-up at our institution for at least two months. Five subjects were followed for a year or longer. Consistent with many TS patients, all subjects had psychiatric co-morbidities. Tic severity and frequency was measured by the Yale Global Tic Severity Scale (YGTSS) over time (average 26 months) in ten subjects. One subject was tested at two weeks follow-up only and thus was excluded from group YGTSS analysis. Final YGTSS scores differed significantly from preoperative baseline. The average (n=10) improvement relative to baseline in the Total Score was 54% (95% confidence interval (CI): 37–70); average improvement relative to baseline in the YGTTS Motor tic, Phonic tic, and Impairment subtests was 46% (95% CI: 34–64), 52% (95% CI: 34–72), and 59% (95% CI: 39–78), respectively. There were no intraoperative complications. Following surgery, one subject underwent wound revision due to a scalp erosion and wound infection; the implanted DBS system was successfully salvaged with surgical revision and combined antibiotic therapy. Stimulation-induced adverse-effects did not prevent the use of the DBS system, although one subject is undergoing a trial period with the stimulator off. This surgical series adds to the literature on CM-Pf DBS and supports its use as an effective and safe therapeutic option for severe refractory TS.

The Use of Deep Brain Stimulation in Tourette Syndrome

“…Nonetheless, adolescence is a crucial period for social, emotional and educational development and preventing younger patients with severe debilitating TS receiving treatment could impact negatively on independence and wellbeing into adult life. This is supported by beneficial reports in younger patients including a 17 year old with SIBs that prevented full time school attendance who showed markedly improved social integration post DBS [ 37 ]. Consequently, recent recommendations argue against strict age criteria and suggest that younger patients should be reviewed on a case by case basis, involving a local ethics committee.…”

“…Adverse effects included a scalp erosion due to compulsive picking, and an abdominal haematoma. These and other open label studies [ 24 , 25 , 26 , 27 , 28 , 29 , 30 , 31 , 32 , 33 , 34 , 35 , 36 , 37 , 38 ] are outlined in Table 1 and strongly indicated that thalamic stimulation may have a beneficial therapeutic role in TS for both tic severity as well as comorbid symptoms.…”

Deep Brain Stimulation for Tourette’s Syndrome: The Case for Targeting the Thalamic Centromedian–Parafascicular Complex

“…An expansion of this series was recently published, including additional targets (85). As Table 1 shows, results from double-blinded randomized controlled trials and single-case studies or small surgical series tend to support the effectiveness of intralaminar thalamus DBS for TS (70–72, 75, 77–79, 81–83, 86). …”

Deep brain stimulation for Tourette’s syndrome

“…To date, the majority of TS DBS treatment studies has focused on the thalamus due to its strategic location between motor areas of the cerebral cortex and motorrelated subcortical structures, particularly the basal ganglia and cerebellum [33,34]. A retrospective study of several patients with refractory TS and psychiatric comorbidities reported that DBS of the thalamic centromedian-parafascicular (CM-Pf) complex was associated with a 46% improvement in motor tics and 52% improvement in phonic tics, as measured by the Yale Global Tic Severity Scale (YGTSS) at follow-up (mean duration: 26 months) [34]. Moreover, DBS of this thalamic region markedly improved the patients' social, occupational, and educational functioning.…”

“…In general, DBS of the thalamus has been well tolerated, but patient risk and adverse side effects remain an issue of concern. Reported side effects include the transient blurring of vision, dysarthria, recurrent tension headache, and a single seizure-like episode (after DBS of the CM-Pf [34,36]). Disturbances of eye motility have also been documented, as well as impaired fine motor skills, particularly following DBS of the ventral anterior and ventrolateral motor thalamic regions [38].…”