Pallidal deep brain stimulation for the treatment of DYT6 dystonia: a case report and review of literature

Little is known about the results of pallidal deep brain stimulation (DBS) in DYT6 dystonia. This will be the first report of DYT6 dystonia treated with pallidal DBS from Iran. A 21 years old male patient with DYT6 dystonia underwent bilateral deep brain stimulation. The target of DBS was the sensorimotor region of the posteroventral globus pallidus internus (GPi). DBS parameters included an amplitude of 2.7 V, frequency of 160 Hz, and pulse width of 90 μs which were adjusted according to the patient's response 12 months after surgery. Treatment outcome was measured by the patient's Burke-Fahn-Marsden Dystonia Rating Scale (BFMDRS) score. Before surgery, the patient's BFMDRS score was 32. However, BFMDRS score reduced to 7 at one year follow up after surgery (78% improvement of total score). Dystonic symptoms of extremities and mouth completely resolved. Also speech and swallowing function significantly improved. Although previous observations reported a poor to moderate response in speech, we found DBS as an effective treatment not only for dystonic features, but also for speech improvement of DYT6 dystonia.

Effect of deep brain stimulation in rats selectively bred for reduced prepulse inhibition

BACKGROUND

Sensorimotor gating, measured as prepulse inhibition (PPI) of the acoustic startle reaction (ASR), is disturbed in certain neuropsychiatric disorders, such as schizophrenia, obsessive compulsive disorder, and Tourette's syndrome (TS). Deep brain stimulation (DBS) of the centromedian-parafascicular complex (CM-Pf), globus pallidus internus (in rats the entopeduncular nucleus - EPN), and the ventral striatum (in rats the nucleus accumbens - NAC) has been used for treatment in TS.

OBJECTIVE

We tested whether DBS of these regions would alleviate breeding-induced low PPI in rats.

METHODS

Rats with breeding-induced low and high PPI were bilaterally implanted with electrodes in the CM-Pf, the EPN, or the NAC. After two weeks, they were stimulated or sham stimulated for epochs of 6 days (in the EPN with a current of 20% below the individual threshold for stimulation-induced side effects, in the NAC or CM-Pf with 100 μA and 150 μA). On the 6th day the rats were tested for PPI of ASR.

RESULTS

Stimulation in the CM-Pf with 150 μA significantly alleviated PPI, while NAC stimulation was less effective. In PPI low rats electrode implantation in the EPN already improved PPI, while subsequent stimulation had no additional effect. Startle reaction of PPI low rats was not affected by stimulation of either region.

CONCLUSION

The CM-Pf and the EPN are important for the modulation of sensorimotor gating in rats with breeding-induced low PPI. These rats may therefore be useful to further investigate the pathophysiological mechanisms of deficient sensorimotor gating and also mechanisms of action of DBS in these circumstances.

Deep brain stimulation of globus pallidus internus for DYT1 positive primary generalized dystonia

BACKGROUND

Deep brain stimulation (DBS) of the globus pallidus internus (GPi) is recommended as a promising technique for the management of the primary generalized dystonia (PGD) with DYT1 gene mutation. We present the first report of DBS results in Iranian patients with DYT1 positive PGD.

METHODS

Nine patients who suffered from severely disabling DYT1 positive PGD consecutively were recruited for the study between 2008 and 2010. The patients underwent bilateral deep brain stimulation of the GPi in a single procedure. The mean follow up duration was 8.8 ± 2.2 months. The efficacy of the intervention was evaluated by comparing pre- and post operative scores of patients with Burke-Fahn-Marsden's dystonia Scale (BFMDS). Statistical analysis was performed using SPSS 11.0 software.

RESULTS

Of 9 patients six were female with the mean age of 15.2 ± 5.5 years old (range: 8- 25 years old). The mean for Burke-Fahn-Marsden's Dystonia Rating Scale (BFMDRS) score was 47.22 ± 14.1 before surgery and 12.3 ± 8.2 after follow up, which significantly improved (P=0.0001).The mean stimulation parameters at the last visit were at a frequency of 152.2 ± 32.4 Hz (range 130- 230 Hz), a voltage of 2.6 ± 0.7 V (range 1.1- 4), and a pulse width of 60 μsec. No complication was observed during follow up.

CONCLUSION

Bilateral DBS of the GPi has an encouraging result for the management of DYT1 positive PGD and is recommended as a safe technique for the treatment of these patients. Shorter pulse width in stimulation parameters is suggested for DYT1 dystonia patients.

Rescue GPi-DBS for a Stroke-associated Hemiballism in a Patient with STN-DBS

Background

Hemiballism/hemichorea commonly occurs as a result of a lesion in the subthalamic region.

Case Report

A 38-year-old male with Parkinson’s disease developed intractable hemiballism in his left extremities due to a small lesion that was located adjacent to the right deep brain stimulation (DBS) lead, 10 months after bilateral subthalamic nucleus (STN)-DBS placement. He underwent a right globus pallidus internus (GPi)-DBS lead implantation. GPi-DBS satisfactorily addressed his hemiballism.

Discussion

This case offered a unique look at basal ganglia physiology in human hemiballism. GPi-DBS is a reasonable therapeutic option for the treatment of medication refractory hemiballism in the setting of Parkinson’s disease.

Motor outcome of dystonic camptocormia treated with pallidal neurostimulation

BACKGROUND

Deep brain stimulation of the internal pallidum (GPi-DBS) is effective for various types of drug-refractory primary dystonias. Rare clinical forms as dystonic camptocormia may profit but available data are scarce.

METHODS

We here report on a retrospective clinical assessment of three patients with primary dystonic camptocormia treated with GPi-DBS.

RESULTS

All three patients showed marked response to bilateral GPi-DBS within days to weeks after surgery which was preserved in the long-term (38-45 months after implantation: mean improvement 82% as rated on the Burke Fahn Marsden Dystonia Rating Scale, 89% in the subitem "trunk"). Two patients developed mild stimulation induced speech problems (stuttering or dysarthria) which resolved with reprogramming or were acceptable in return for the control of dystonic symptoms.

CONCLUSIONS

The diagnosis and treatment of camptocormia will continue to require expert knowledge in movement and neuromuscular disorders, but DBS may expand treatment options in this difficult patient population.

Surgery for Tourette syndrome

Tourette syndrome is a chronic neuropsychiatric disorder characterized by motor and vocal tics. In the majority of cases, tics are associated by behavioral disorders such as obsessive-compulsive behavior. First symptoms typically appear in early childhood. Mostly symptoms disappear when adulthood is reached. Treatment options consist of behavioral therapy and medication. In refractory cases, surgery may be an option. In the past, several attempts have been made to treat therapy-refractory patients through neurosurgical ablative procedures. In 1999, deep brain stimulation was introduced as a novel treatment option for patients with intractable Tourette syndrome. Up until now, five brain areas have been used or suggested as potential target areas for deep brain stimulation in Tourette syndrome. In the majority of the published cases, there is a clear effect on tics but most studies consist of only a limited number of patients. A strict patient selection is absolutely mandatory. There is a need for double-blinded multicenter trials with inclusion of more patients.