1. Aetna considers unilateral deep brain stimulators (e.g., stimulation of the ventral intermediate thalamic nucleus, globus pallidus, and subthalamic nucleus) medically necessary durable medical equipment (DME) for the treatment of intractable tremors as a consequence of Parkinson's disease or essential tremor when all of the following criteria are met:

   • Member suffers from disabling upper extremity essential tremor that is not responding satisfactorily to drug therapy or suffers from a disabling tremor of idiopathic Parkinson's disease that is refractory to pharmacotherapy, and 
   • Member does not have other independent diagnoses that could explain the failure to respond to medical treatment, and  
   • Member does not have dementia, severe depression, cerebral atrophy, or Hoehn and Yahr stage V Parkinson's disease (see Note below), and 
   • There is no focal lesion of the basal ganglia (e.g., a space occupying lesion or lacunae) at the target site that would negate the result of thalamic stimulation, and 

   • There is sufficient residual motor function in the upper extremity so that it is reasonable to expect an improvement following the surgery. 

   Note: Hoehn and Yahr Stage V individuals exhibit the following characteristics: 

   • Cachectic state 
   • Invalidism 
   • Cannot stand or walk (need wheelchair assistance, or are unable to get out of bed) 

   • Requires constant nursing care. 

2. Aetna considers bilateral deep brain stimulators (e.g., stimulation of the globus pallidus and subthalamic nucleus) medically necessary DME for the treatment of severe, refractory motor complications of Parkinson's disease when all of the following criteria are met:

   • Presence of at least 2 major symptoms of Parkinsonism (e.g., tremor, rigidity, and bradykinesia); and  
   • Member is levodopa responsive with clearly defined “on” periods; and
   • A minimal score of 30 points on the motor portion of the United Parkinson's Disease Rating Scale (UPDRS) when the member has been off medication for about 12 hours (scores on this scale range from 0 to 108; higher values indicate greater severity of symptoms); and
   • Motor complications that can not be managed with medication; and

   • Member does not have dementia, severe depression, cerebral atrophy, or advanced (Hoehn and Yahr stage V) Parkinson's disease.

3. Aetna considers unilateral or bilateral deep brain stimulators (e.g., stimulation of the globus pallidus and subthalamic nucleus) medically necessary DME for the treatment of persons 8 years of age or older with intractable primary dystonia, including generalized and/or segmental dystonia, hemidystonia and cervical dystonia.

4. Aetna considers deep brain stimulation (DBS) for tremor from other causes such as trauma, multiple sclerosis (MS), degenerative disorders, metabolic disorders, infectious diseases, and drug-induced movement disorders experimental and investigational because DBS has not been shown to be effective for treating tremors due to these other causes.

5. Aetna considers DBS experimental and investigational for all other indications, including the treatment of Alzheimer's disease, Parkinson’s disease-related dysarthria/speech deficits, head or voice tremor, depression, epilepsy, chronic cluster headache, obsessive-compulsive disorder, and Tourette syndrome because there is insufficient evidence to support its effectiveness for these indications.

See also CPB 153 - Thalamotomy, and  CPB 307 - Parkinson's Disease.

Essential tremor is a common movement disorder afflicting 5 to 10 million Americans.  It is characterized primarily by an action and postural tremor most often affecting the arms, but it can also affect other body parts.  Essential tremor is a progressive neurological disorder and can result in severe disability in some individuals.  Although there is no cure for essential tremor, pharmacotherapy and surgery can provide some relief.  Primidone and propranolol are first-line treatments.  Other medications include benzodiazepines, gabapentin, and topiramate.  Patients with medication-resistant tremor may benefit from thalamotomy or deep brain stimulation (DBS) of the thalamus.  Medical and surgical interventions can provide benefit in up to 80 % of patients with essential tremor.  Deep brain stimulation is also an effective treatment for patients with advanced Parkinson's disease (PD) and motor complications that can no longer be improved by adjustment of medical therapy.  The most common targets for implantation of deep brain stimulators are the subthalamic nucleus and globus pallidus internus.

The American Academy of Neurology's practice parameter on the treatment of PD with motor fluctuations and dyskinesia (Pahwa et al, 2006) stated that pre-operative response to levodopa predicts better outcome after DBS of the subthalamic nucleus.

Deuschl and Bain (2002) noted that the appropriate selection of patients is essential for the outcome of surgical relief of tremors.  The selection criteria should include: (i) motor symptoms causing a relevant disability in activities of daily living, despite optimal pharmacotherapy; (ii) biological age of the patient; (iii) neurosurgical contraindications; and (iv) the patient is neither demented nor severely depressed.

On the other hand, DBS is an investigational therapy in other conditions such as such as trauma, multiple sclerosis (MS), degenerative disorders, metabolic disorders, infectious diseases, and drug-induced movement disorder.  Experience with DBS in the treatment of tremor due to MS is limited to small case series or case reports.  Currently, it is impossible to predict which patients will benefit from this treatment.  Furthermore, frequent stimulator adjustments are needed to maintain optimum limb functions; and long-term effectiveness has not been demonstrated.  Prospective, randomized, controlled studies with large sample size are needed to ascertain the long-term efficacy of DBS in patients with MS.

Pallanti et al (2004) stated that more results are needed before the effectiveness of non-pharmacologic treatments (e.g., DBS) for obsessive-compulsive disorder can be determined.  Deep brain stimulation has also been examined for the treatment of epilepsy, chronic cluster headache, and Tourette syndrome.  However, there is currently insufficient evidence to support its effectiveness of these indications.

Primary generalized dystonia associated with the early-onset generalized dystonia gene can cause severe disability, affecting a person’s ability to perform activities of daily living.  Pharmacotherapy has been inadequate in alleviating the motor dysfunctions.  Deep brain stimulation of the bilateral globus pallidus internus has been reported to reduce these debilitating motor abnormalities.  The FDA approved DBS for the treatment of primary dystonia via the humanitarian device exemption process, and its summary of safety and probable benefit stated that although there are a number of serious adverse events experienced by patients treated with DBS, in the absence of therapy, chronic intractable dystonia can be very disabling and in some cases, progress to a life-threatening stage or constitute a major fixed handicap.  When the age of dystonia occurs prior to the individual reaching their full adult size, the disease not only can affect normal psychosocial development but also cause irreparable damage to the skeletal system.  As the body of the afflicted person is contorted by the disease, the skeleton may be placed under constant severe stresses that may cause permanent disfigurement.  Risks associated with DBS for dystonia appear to be similar to the risk associated with the performance of stereotactic surgery and the implantation of DBS systems for currently approved indications, except when used in either child or adolescent patients groups.

In this regard, Eltahawy et al (2004) reported that bilateral pallidal stimulation is effective in management of selected cases of intractable cervical dystonia.  Furthermore, the findings of a recent prospective, controlled, multicenter study (Vidailhet et al, 2005) support the safety and effectiveness of the use of bilateral stimulation of the internal globus pallidus in selected patients with primary generalized dystonia.  However, according to a report by the American Academy of Neurology (Zesiewicz et al, 2005), there is no evidence of a synergistic effect on limb tremor with bilateral DBS, and there are insufficient data regarding the risk:benefit ratios of unilateral versus bilateral DBS.  Furthermore, the report also stated that there is insufficient evidence to make recommendations regarding the use of DBS for head or voice tremor.

There is currently insufficient scientific evidence that DBS is effective in treating patients with PD-related dysarthria/speech deficit.

In a review, Schulz and Grant (2000) examined the different treatment approaches for patients with PD and their effects on speech.  Therapeutic approaches reviewed include speech therapy, pharmacological, and surgical.  The authors stated that research from the 1950s through the 1970s had not shown significant improvements following speech therapy.  On the other hand, recent research has shown that speech therapy (when PD patients are optimally medicated) has proven to be most effective in improving voice and speech function.  Pharmacotherapies in isolation do not appear to significantly improve voice and speech function in PD patients across research studies.  Neurosurgical interventions including pallidotomy and DBS may be significant treatment options which improve voice and speech function in some PD patients.  These investigators stated that future studies should examine the effects of combined treatment approaches.  Perhaps the combination of pharmacological, neurosurgical, and speech treatment will prove superior to treatments combining pharmacological and neurosurgical approaches, or pharmacotherapies and speech therapy in improving the communication abilities of patients with PD.

Pinto, et al. (2004) stated that dysarthria in PD can be characterized by monotony of pitch and loudness, reduced stress, variable rate, imprecise consonants, and a breathy and harsh voice.  Use of levodopa to replenish dopamine concentrations in the striatum appears to improve articulation, voice quality, and pitch variation, although some studies showed no change in phonatory parameters.  Traditional speech therapy can lead to improvement of dysarthria, and intensive programs have had substantial beneficial effects on vocal loudness.  Unilateral surgical lesions of subcortical structures are variably effective for the alleviation of dysarthria, whereas bilateral procedures typically lead to worsening of speech production (Pinto, et al., 2004)  Among DBS procedures, only stimulation of the subthalamic nucleus improves some motor components of speech although intelligibility seems to decrease after surgery.  Due to the variable treatment effects on Parkinsonian speech, management of dysarthria is still challenging for the clinician.

Farrell and colleagues (2005) examined the effects of neurosurgical management of PD, including pallidotomy, thalamotomy, and DBS on perceptual speech characteristics, speech intelligibility, and oromotor function in a group of 22 patients with PD.  The surgical subjects were compared with a group of 25 non-neurologically impaired individuals matched for age and sex. In addition, the study examined 16 patients with PD who did not undergo neurosurgical treatment to control for disease progression.  Results revealed that neurosurgical intervention did not significantly change the surgical subjects' perceptual speech dimensions or oromotor function despite significant post-operative improvements in ratings of general motor function and disease severity.

There is currently insufficient scientific evidence that DBS is effective in treating patients with depression.  Eitan and Lerer (2006) stated that non-pharmacological modalities for the treatment of depression such as magnetic seizure therapy, vagus nerve stimulation, and DBS are at various stages of research development.  The authors reviewed the development and technical aspects of these treatments, their potential role in the treatment of major depression, adverse effects, and putative mechanism of action.  These researchers concluded that although these modalities hold considerable promise, these novel brain stimulation techniques need to be further developed before they achieve clinical acceptability.  Carpenter et al (2006) noted that DBS for severe intractable depression has been studied in two pilot studies with very few patients to date.  They stated that further investigations are currently underway in order to more fully evaluate DBS with the hope of substantially improving the treatment of refractory depression.  These findings are in agreement with that of (Holtzheimer and Nemeroff, 2006) who stated that for the most part, the data on DBS for the treatment of depression are preliminary, and more study is needed to clarify its potential clinical benefit.