Near-infrared stimulation on globus pallidus and subthalamus

Near-infrared stimulation (NIS) is an emerging technique used to evoke action potentials in nervous systems. Its efficacy of evoking action potentials has been demonstrated in different nerve tissues. However, few studies have been performed using NIS to stimulate the deep brain structures, such as globus pallidus (GP) and subthalamic nucleus (STN). Male Sprague-Dawley rats were randomly divided into GP stimulation group (n=11) and STN stimulation group (n=6). After introducing optrodes stereotaxically into the GP or STN, we stimulated neural tissue for 2 min with continuous near-infrared light of 808 nm while varying the radiant exposure from 40 to 10 mW. The effects were investigated with extracellular recordings and the temperature rises at the stimulation site were also measured. NIS was found to elicit excitatory responses in eight out of 11 cases (73%) and inhibitory responses in three cases in the GP stimulation group, whereas it predominantly evoked inhibitory responses in seven out of eight cases (87.5%) and an excitatory response in one case in STN stimulation group. Only radiation above 20 mW, accompanying temperature increases of more than 2°C, elicited a statistically significant neural response (p<0.05). The responsiveness to NIS was linearly dependent on the power of radiation exposure.

Treatment of dystonia with deep brain stimulation

Pallidal deep brain stimulation (DBS) is an established treatment option for medically refractive dystonia. The mechanism by which globus pallidus pars interna (GPi) DBS improves dystonia is still unclear. Primary generalized dystonia usually responds well to this therapy, as recently confirmed in two well-designed, double-blind, controlled trials; however, predictors of outcome within this population are not well known. The role of GPi DBS in idiopathic cervical dystonia resistant to treatment with botulinum toxin, in tardive dystonia, and in some types of secondary dystonia are emerging as populations of patients who may also benefit, but outcomes are not well documented. Serious complications from this therapy are rare. Future research will likely continue to address the most appropriate programming settings for various populations of dystonia, the mechanism by which DBS affects dystonia, and the possibility of alternative brain targets that might have less associated side effects or greater efficacy than the GPi.

Antero-ventral internal pallidum stimulation improves behavioral disorders in Lesch-Nyhan disease

The Lesch-Nyhan syndrome is an X-linked recessive disorder caused by a deficiency in hypoxanthine-guanine phosphoribosyl transferase, a purine salvage enzyme. Affected individuals exhibit a characteristic neurobehavioral disorder with delayed acquisition of motor skills, dystonia, severe self-mutilations, and aggressive behavior. Deep brain stimulation has been previously proposed for controlling isolated involuntary movements and psychiatric disorders. We applied a double bilateral simultaneous stimulation to limbic and motor internal pallidum in one patient for controlling both behavioral and movement disorders, respectively. The injurious compulsions disappeared; dystonia and dyskinesia were decreased at 28 months follow-up.

Mood improvement after deep brain stimulation of the internal globus pallidus for tardive dyskinesia in a patient suffering from major depression

Deep brain stimulation (DBS) has the unique characteristic to very precisely target brain structures being part of functional brain circuits in order to reversibly modulate their function. It is an established adjunctive treatment of advanced Parkinson's disease and has virtually replaced ablative techniques in this indication. Several cases have been published relating effectiveness in neuroleptics-induced tardive dyskinesia. It is also investigated as a potential treatment of mood disorders. We report on the case of a 62 years old female suffering from a treatment refractory major depressive episode with comorbid neuroleptic-induced tardive dyskinesia. She was implanted a deep brain stimulation treatment system bilaterally in the globus pallidus internus and stimulated for 18 months. As well the dyskinesia as also the symptoms of depression improved substantially as measured by the Hamilton Rating Scale of Depression (HRSD) score and the Burke-Fahn-Marsden-Dystonia-Rating-Scale (BFMDRS) score. Scores dropped for HRSD from 26 at baseline preoperatively to 13 after 18 months; and for BFMDRS from 27 to 17.5. This case illustrates the potential of deep brain stimulation as a technique to be investigated in the treatment of severe and disabling psychiatric and movement disorders. DBS at different intracerebral targets being actually investigated for major depression might have similar antidepressant properties because they interact with the same cortico-basal ganglia-thalamocortical network found to be dysfunctional in major depression.

First case of X-linked dystonia-parkinsonism (“Lubag”) to demonstrate a response to bilateral pallidal stimulation

"Lubag" or X-linked dystonia-parkinsonism (XDP) is a genetic syndrome afflicting Filipino men. Intracranial surgical procedures for Lubag have been unsuccessful. We report a 45-year-old Filipino male with genetically confirmed XDP who underwent bilateral pallidal deep brain stimulation (DBS) surgery. The patient started to exhibit improvement on initial programming, most notably of his severe jaw-opening dystonia. At 1-year follow-up, his Burke-Fahn-Marsden dystonia score and motor Unified Parkinson's Disease Rating Scale score were improved by 71% and 62%, respectively, with the stimulators on compared to stimulators off state. Bilateral pallidal DBS may be a viable option for Lubag patients with medically refractory symptoms.

Lower stimulation frequency can enhance tolerability and efficacy of pallidal deep brain stimulation for dystonia

We report the case of a patient with medically refractory primary dystonia who was treated with bilateral pallidal deep brain stimulation. Stimulation at 130 Hz or higher, by means of the more ventral contacts generated capsular side effects, which made their use impractical. Consequently, the patient was treated for 9 months at 130 to 185 Hz, by means of the more dorsal contacts, achieving modest results. By reducing the stimulation frequency to 80 Hz, we were able to activate the ventral contacts without inducing side effects. Within days, the patient experienced a dramatic improvement in function that has persisted for 1 year. A further reduction in stimulation frequency to 60 Hz resulted in a worsening of his symptoms. We conclude that chronic stimulation at frequencies of <100 Hz may be efficacious in dystonia and may enhance the tolerability of stimulation by means of contacts that are positioned posteroventrally within the internal globus pallidus, nearer the internal capsule.

Deep brain stimulation for torsion dystonia

Deep brain stimulation (DBS) at the globus pallidus pars internus (GPi) is an effective treatment for some patients with medically refractory torsion dystonia. In this chapter we review the classification and treatment of torsion dystonia including the current indications for DBS surgery. Details of the DBS procedure and programming of the DBS devices are discussed. Pallidal DBS is most effective in patients with primary generalized dystonia. Children and adolescents possessing the DYT1 gene mutation may respond best of all. Patients with cervical dystonia may also improve with pallidal DBS but definitive clinical evidence is lacking. As a group, patients with secondary dystonias respond less well to DBS than do patients with primary dystonia; however, patients with dystonia secondary to anoxic brain injury who have grossly intact basal ganglia anatomy, and patients with tardive dystonia may represent secondary dystonia subtypes for whom pallidal DBS is a viable option.

Deep brain stimulation in Tourette's syndrome: two targets?

In this report, we describe the effects of bilateral thalamic stimulation in one patient and of bilateral pallidal stimulation in another patient. Both patients suffered from intractable Tourette's syndrome (TS). Any conservative treatment had failed or had been stopped because of unbearable side effects in the 2 patients. In both cases, there was no comorbidity except for associated behavioral symptoms (compulsions). Electrodes were implanted at the level of the medial part of the thalamus (centromedian nucleus, the substantia periventricularis, and the nucleus ventro-oralis internus) in one patient and in the posteroventral part of the globus pallidus internus (GPi) in the other patient. In both cases, deep brain stimulation (DBS) resulted in a substantial reduction of tics and compulsions. These data show that bilateral DBS of the thalamus as well as of the GPi can have a good effect on tics and behavioral symptoms in patients suffering from intractable TS.

A dominant bursting electromyograph pattern in dystonic conditions predicts an early response to pallidal stimulation

Although chronic pallidal deep brain stimulation (DBS) is effective in the treatment of medically intractable dystonia, there is no way of predicting the variations in clinical outcome, partly due to our limited understanding of the pathophysiological mechanisms underlying this condition. We recorded electromyographic (EMG) activity from the most severely affected muscle groups in seven dystonia patients before and after pallidal DBS. Patient EMG recordings could be classified into two groups: one consisting of patients who at rest demonstrated a dominant low frequency component of activity on power spectral analysis (ranging from 2 to 5 Hz), and one group in which this dominant pattern was absent. Early postoperative improvements (within 2-3 days) were observed in the former group, whereas the latter group benefited more gradually (over several months). Analysis of EMG activity may provide a sensitive means of identifying dystonic patients who are likely to be most responsive to functional neurosurgical intervention.

Different mechanisms may generate sustained hypertonic and rhythmic bursting muscle activity in idiopathic dystonia

Despite that deep brain stimulation (DBS) of the globus pallidus internus (GPi) is emerging as the favored intervention for patients with medically intractable dystonia, the pathophysiological mechanisms of dystonia are largely unclear. In eight patients with primary dystonia who were treated with bilateral chronic pallidal stimulation, we correlated symptom-related electromyogram (EMG) activity of the most affected muscles with the local field potentials (LFPs) recorded from the globus pallidus electrodes. In 5 dystonic patients with mobile involuntary movements, rhythmic EMG bursts in the contralateral muscles were coherent with the oscillations in the pallidal LFPs at the burst frequency. In contrast, no significant coherence was seen between EMG and LFPs either for the sustained activity separated out from the compound EMGs in those 5 cases, or in the EMGs in 3 other cases without mobile involuntary movements and rhythmic EMG bursts. In comparison with the resting condition, in both active and passive movements, significant modulation in the GPi LFPs was seen in the range of 8-16 Hz. The finding of significant coherence between GPi oscillations and rhythmic EMG bursts but not sustained tonic EMG activity suggests that the synchronized pallidal activity may be directly related to the rhythmic involuntary movements. In contrast, the sustained hypertonic muscle activity may be represented by less synchronized activity in the pallidum. Thus, the pallidum may play different roles in generating different components of the dystonic symptom complex.

Pallidal stimulation reduces treatment-induced dyskinesias in “minimal-change” multiple system atrophy

Deep brain stimulation therapy is increasingly gaining acceptance in the management of levodopa-induced dyskinesia and fluctuations in idiopathic Parkinson's disease. It is generally not recommended for the other forms of parkinsonism such as progressive supranuclear palsy or multiple system atrophy where the response to levodopa is usually poor and disease progression more rapid, making any benefit short-lived. Here, we present an autopsy-confirmed case of "minimal-change" multiple system atrophy in whom pallidal stimulation surgery was effective in abolishing severe levodopa-induced dyskinesia.

Pallidal deep brain stimulation and L-dopa do not improve qualitative aspects of skilled reaching in Parkinson's disease

OBJECTIVE

To determine effects of dopaminergic medication and pallidal deep brain stimulation (DBS) on skilled reach in Parkinson's disease (PD).

BACKGROUND

PD is a neurodegenerative disorder affecting motor control. While speed and execution of movements are improved by L-dopa, not all motor symptoms are alleviated. Little is known about the effects of DBS or medication on reaching.

DESIGN METHOD

Eight PD patients with unilateral pallidal DBS reached with the contra-lateral hand for a piece of food, placing it in the mouth, and returning to starting position. Testing was performed on no treatment, medication only, DBS only, and combined treatment. Reaches were digitally recorded and analyzed on a 21 point scale adapted from Eshkol-Wachman Notation. Analysis was blinded, with patients compared to age-matched controls.

RESULTS

Patients were tested 6-13 months after surgery. All showed significant improvement clinically and in UPDRS (III) scores. The following data were obtained on the reaching scale: normal controls 16.5-21.0 (mean 18.3), no treatment 3.0-12.5 (mean 7.4), medication only 7.0-14.0 (mean 10.3), DBS only 4.5-16.0 (mean 9.2), combined treatment 4.0-15.0 (mean 9.5). The difference between controls and all treatment groups was statistically significant (P<0.005). All aspects of reach were compromised. No significant differences were found among the four conditions.

CONCLUSIONS

This study is consistent with accumulating evidence that some aspects of motor performance in PD patients, such as reaching, are resistant to L-dopa. Also, pallidal DBS does not improve those parameters that are resistant to L-dopa, either alone or in combination with medication.

Sporadic rapid-onset dystonia-parkinsonism syndrome: failure of bilateral pallidal stimulation

We report on a woman who had a severe sporadic nonprogressive dystonia-parkinsonism syndrome with rapid onset of symptoms at age 21. Secondary causes for dystonia were ruled out. No response to levodopa/carbidopa was seen. The patient fulfilled all diagnostic criteria of rapid-onset dystonia-parkinsonism, except for autosomal-dominant inheritance. Bilateral deep brain stimulation of the globus pallidus failed to alleviate her symptoms.

Stimulation of the subthalamic nucleus in a patient with Parkinson disease and essential tremor

BACKGROUND

The preferred surgical target for the treatment of Parkinson disease (PD) is either the internal globus pallidus or the subthalamic nucleus (STN); the target for treatment of essential tremor (ET) is the thalamic subnucleus ventralis intermedius (Vim). Some patients with PD have coexistent ET, and the identification of a single surgical target to treat both parkinsonian motor symptoms and ET would be of practical importance.

OBJECTIVE

To describe the use of the STN target in deep brain stimulator (DBS) surgery to treat PD motor symptoms and the action-postural tremor of ET.

DESIGN

Case report.

PATIENT

A 62-year-old man had a greater than 30-year history of action-postural tremor in both hands, well controlled with beta-blockers for more than 20 years. He developed resting tremor, bradykinesia, and rigidity on his right side that progressed to his left side during the past 10 years. Dopaminergic medication improved his rigidity and bradykinesia, with only mild improvement of his resting tremor and no effect on his action-postural tremor.

INTERVENTIONS

Left pallidotomy followed by placement of a left DBS in the Vim and subsequent placement of a right STN DBS.

MAIN OUTCOME MEASURES

Control of symptoms of PD and ET.

RESULTS

The left pallidotomy controlled the patient's parkinsonian motor symptoms on the right side of his body, but did not affect the action-postural component of his tremor. The symptoms on the left side of the body, including both an action-postural and a resting tremor (as well as the rigidity and bradykinesia), improved after placement of a single right STN DBS.

CONCLUSION

Placement of an STN DBS should be considered as the procedure of choice for surgical treatment of patients with a combination of PD and ET.

Acute stimulation in the external segment of the globus pallidus improves parkinsonian motor signs

High frequency (>100Hz) electrical stimulation in both the external (GPe) and internal (GPi) segments of the globus pallidus was effective in improving parkinsonian motor signs. Improvement generally occurred at short latency (<5-10 seconds) in both GPe and GPi but was often (50% of the time) delayed in GPi. Dyskinetic movements were observed during stimulation within GPe and GPi but were more frequent in GPe (20% vs. 9%). These findings suggest that electrical stimulation in both GPe and GPi may ameliorate parkinsonian motor signs. The mechanisms responsible for these observations, however, may differ. The tendency for delayed responses with GPi stimulation suggests a more complex spatial-temporal profile of stimulation on the electrical activity of GPi neurons and/or its effect on network activity in pallido-thalamo-cortical circuitry. The rarity of delayed effects with GPe stimulation suggests a more direct role of synaptic inhibition or normalization of neuronal activity of GPi either directly by means of activation of striatopallidal fibers passing through GPe (direct pathway), by means of activation of GPe-->GPi or GPe-->subthalamic nucleus projections (indirect pathway) or indirectly by means of the tonic activation of adjacent fiber pathways. These data provide a rationale for the exploration of electrical stimulation in GPe in patients with medically intractable Parkinson's disease and provide a basis on which to develop further investigations into the use of chronic electrical stimulation for the treatment of Parkinson's disease and other movement disorders.

Accelerometric measurement of involuntary movements during pallidal deep brain stimulation of patients with generalized dystonia

Accelerometric activity during rest and posture was quantified in the upper dominant limb of 14 patients with primary or secondary dystonia and five healthy control subjects. Data were recorded before and after bilateral implantation of the stimulating electrodes in the Globus Pallidus internus. Clinical evaluation was based on the Burke-Marsden-Fahn's Dystonia Rating Scale (BMFDRS). For the patient group, I(t), the integral (i.e. area) of the acceleration power spectrum over the total frequency range (0.6-16 Hz) decreased as the clinical state of the patients improved following deep brain stimulation (p < 0.01) during rest and posture. Ten days after surgery, there were no I(t) differences between control subjects and patients (p > 0.05). A significant correlation was found between the global BMFDRS scores and I(t) for rest (p < 0.01) but not for posture. No significant correlation was found between I(t) and a partial BMFDRS score for the right arm for rest or posture. The integral I(t) provides a valid indicator of the motor activity generated by the arm of the patient but further analyses are needed to monitor patients' progress not only during their hospitalization but also after they are released from the hospital, and to understand why this measure does not correlate with partial BMFDRS scores.

Bilateral globus pallidus internus deep brain stimulation in tardive dyskinesia: A case report

The clinical response of a 53-year-old woman with tardive dyskinesia treated with bilateral globus pallidus interna deep brain stimulation is described. At 18 months follow-up, her Burke-Fahn-Marsden Dystonia Rating Scale score fell from 52 (preoperative) to 21 (60% improvement).

Long-term results of bilateral pallidal stimulation in Parkinson's disease

We followed up 11 patients for up to 5 years after bilateral pallidal deep brain stimulation for advanced Parkinson's disease. Dyskinesias remained significantly reduced until the last assessment. The initial improvement of off-period motor symptoms and fluctuations, however, was not sustained and gradually declined. Beneficial effects of pallidal deep brain stimulation on activities of daily living in the on- and off-period were lost after the first year. Replacement of pallidal electrodes into the subthalamic nucleus in four patients could restore the initial benefit of deep brain stimulation and allowed a significant reduction of dopaminergic drug therapy.

Bilateral globus pallidus stimulation for Huntington's disease

Bilateral globus pallidus internus (GPi) deep brain stimulation (DBS) was performed in a patient with Huntington's disease (HD) with severe chorea. Stimulation at 40 and 130 Hz improved chorea. Stimulation at 130 Hz slightly worsened bradykinesia overall, whereas 40 Hz had little effect. A [15O] H2O positron emission tomography showed increased regional cerebral blood flow in motor decision making and execution areas more evident at 40 Hz. Adjustment of stimulation parameters in GPi DBS may have the potential to optimize the motor response in HD, improving chorea without aggravating bradykinesia.