Deep Brain Stimulation for Parkinson’s Disease
Deep Brain Stimulation for Parkinson’s Disease

PARKINSON’S DISEASE (PD) is a chronic and degenerative brain disorder that results in motor impairment. After 4 to 6 years of treatment, medication-induced complications can develop. As the disease advances, symptoms become more severe and other problems related to the patient’s gait, cognition and musculoskeletal system develop.
In Singapore, PD is the second most common neurological disorder. Local studies have shown that the disease occurs in three out of every 1,000 people aged 50 and above. It is estimated that there are between 4,000 to 5,000 PD patients in Singapore [1].

Oral medication is the standard of care in early PD; however, as the disease progresses and medication-induced complications develop, patients may become refractory to this treatment option.

Deep Brain Stimulation (DBS) is the most common surgical treatment performed on people with PD, when medications alone are no longer able to adequately control their motor symptoms. It is also required when medication-related problems, particularly levodopa-induced dyskinesia (involuntary movements) and motor fluctuations, significantly affect the quality of life of the patient.

DBS therapy is an adjustable and reversible surgical treatment and more than 140,000 patients worldwide have been treated with DBS. In Singapore, more than 100 patients have benefited from DBS therapy. DBS has been approved for the following indications:

  • Essential tremor
  • Parkinson’s disease
  • Primary dystonia
  • Obsessive-compulsive disorder
  • Epilepsy
SYMPTOMS OF PARKINSON’S DISEASE

PD is clinically defined by the presence of bradykinesia (slowness in movement), with at least one cardinal motor feature (rigidity or rest tremor).

In addition to the cardinal motor features, patients with PD also have non-motor symptoms involving a multitude of functions, such as disorders of the sleep–wake cycle regulation, cognitive impairment, disorders of mood and affect, autonomic dysfunction (mainly orthostatic hypotension, urogenital dysfunction, constipation and hyperhidrosis), as well as sensory symptoms (most prominently hyposmia) and pain.

Deep Brain Stimulation for Parkinson’s Disease Deep Brain Stimulation for Parkinson’s Disease

Parkinson’s Patients with Poorer Quality of Life May Benefit the Most from Deep Brain Stimulation, Study Finds
Parkinson’s Patients with Poorer Quality of Life May Benefit the Most from Deep Brain Stimulation, Study Finds

Individuals with Parkinon’s disease who have worse quality of life due to their disease-related impairments may benefit most from treatment with deep-brain stimulation.

The study with that finding, “Quality of life predicts outcome of deep brain stimulation in early Parkinson disease,” was published by the journal Neurology.

Deep-brain stimulation (DBS) is an invasive surgical technique in which thin wires are implanted in the brain to deliver electric pulses to specific areas, such as the subthalamic nucleus (STN), to ease motor symptoms in patients for whom standard medications are not effective.

Studies have shown that DBS can effectively help manage motor symptoms and reduce the necessary daily dose of medication, improving quality of life in those with advanced or early-stage Parkinson’s.

In the most recent study researchers reviewed the trial data to understand which factors contributed to the detectable changes in disease-specific quality of life, as measured using the 39-item Parkinson’s Disease Questionnaire summary index (PDQ-39-SI). The self-reported questionnaire assesses Parkinson’s-specific health across eight quality-of-life dimensions.

The analysis revealed that quality of life over the two years of follow-up correlated with the initial value of the PDQ-39-SI in both treatment groups. Still, this association was more pronounced among patients who were treated with STN-DBS.

Patients with very mild impairment due to Parkinson’s, corresponding to PDQ-39-SI values lower than 15, were found not to benefit from STN-DBS as compared to patients treated with standard care alone. In contrast, patients treated with STN-DBS who had PDQ-39-SI sores higher than 15 (worse quality of life) at the beginning of the study experienced better quality of life changes.

“In patients with very low baseline ratings on the PDQ-39-SI, the natural progression of impairment of [quality of life] may outweigh the improvement achieved by STN-DBS,” researchers wrote. “On the other hand, some patients with very modest impairment of their [quality of life] seem to have less to gain from STN-DBS,” they added.

Patients’ cognitive status before the treatment, as determined by the Mattis DementiaRating Scale (MDRS), was not predictive of change in quality of life in either treatment group. However, higher scores for depression and poorer mood correlated with larger improvements in quality of life among patients in the STN-DBS group.

These findings “may indicate that these patients have a potential for nonmotor improvement to gain from surgery,” researchers suggested.

Changes in quality of life during the two years of follow-up were independent of patient age, disease duration, duration of motor complications, severity of parkinsonian motor manifestation under levopoda therapy, or treatment complications.

Supported by these findings, the team believes that “baseline impairment of quality of life is (…) a reasonable aspect to consider for the decision to treat with STN-DBS.”

“The subjective individual suffering as measured with the PDQ-39-SI should be taken into account as a predictive factor for outcome when selecting patients with early motor complications for STN-DBS,” researchers concluded.

WORLD PARKINSON DAY
WORLD PARKINSON DAY

Around 10 million people in the world, around 150 thousand are thought to have Parkinson’s disease. As the incidence of Parkinson’s disease increases with age, the incidence of the disease is increasing in countries where the elderly population is high. In the United States, one out of every 100 people over 65 years of age is suffering from Parkinson’s disease, with about 1 million Americans living with Parkinson’s disease, and about 60,000 new diagnoses are made each year. It is estimated about 10 thousand new diagnoses occur every year in Turkey. Depending on the growing elderly population, it can be said that there will be an explosion in Parkinson’s disease in the coming years.

 

Parkinson’s disease is the only neurodegenerative disease in which symptoms can be cured and the patient’s life can be reduced less. There is information that early treatment in Parkinson’s helps delay the progression of the disease and prolongs the quality of life. For this reason, the 11th of April of each year is declared as  World Parkinson’s Disease Day “throughout the world to create social awareness and awareness.