Decisions about deep brain stimulation therapy in Parkinson’s disease

Abstract

Parkinson' s disease (PD), a hypokinetic movement disorder characterized by the classic tetrad of bradykinesia, rest tremor, plastic rigidity, and postural disturbances 1,2 , is a neurodegenerative disorder with an increasing impact on the Brazilian social and healthcare system, mirroring known demographic-epidemiological changes such as aging of the population and widening of the apex of the age pyramid 3,4 . Considering a prevalence of 3.3% in those aged 65 or older in the Brazilian population 5 , the country has at least 200,000 patients living with the disorder, a definitive challenge to the public health system. ABSTRACTParkinson's disease can be treated surgically in patients who present with motor complications such as fluctuations and dyskinesias, or medically-refractory disabling tremor. In this review, a group of specialists formulated suggestions for a preoperative evaluation protocol after reviewing the literature published up to October 2017. In this protocol, eligibility and ineligibility criteria for surgical treatment were suggested, as well as procedures that should be carried out before the multidisciplinary therapeutic decisions. The review emphasizes the need to establish "DBS teams", with professionals dedicated specifically to this area. Finally, surgical target selection (subthalamic nucleus or globus pallidus internus) is discussed briefly, weighing the pros and cons of each target.Keywords: Parkinson disease; deep brain stimulation; reference standards; basal ganglia; neurosurgical procedures. RESUMOA doença de Parkinson pode ser tratada cirurgicamente em pacientes que desenvolveram complicações motoras, como flutuações e discinesias, ou tremores refratários ao uso de medicação. Nesta revisão, um grupo de especialistas formulou sugestões para um protocolo de avaliação pré-operatória, depois de revisar a literatura publicada até outubro de 2017. Neste protocolo, são sugeridos critérios de elegibilidade e inadmissibilidade para tratamento cirúrgico, bem como procedimentos que devem ser realizados antes das decisões terapêuticas multidisciplinares. A revisão enfatiza a necessidade de estabelecer "equipes de DBS", com profissionais dedicados especialmente a esta área. Ao final, a seleção do alvo cirúrgico (núcleo subtalâmico ou globo pálido interno) é discutida brevemente, ponderando prós e contras de cada escolha.Palavras-chave: doença de Parkinson; estimulação cerebral profunda; padrões de referência; gânglios da base; procedimentos neurocirúrgicos.

Medical management after subthalamic stimulation in Parkinson’s disease: a phenotype perspective

“…As detailed below, when we "add" the STN stimulation to patients who are already under high doses of dopaminergic drugs, there is an over-inhibition of the STN activity 13 . This inhibition, in turn, may 'release the horses' and culminates in a worsening of dyskinesias and increases the risk of hyperdopaminergic syndrome, such as impulse control disorders during the short-term period after surgery [1][2][3][4][5][6][7][8][9][10][11][12][13][14] . Thus, a careful and individualized medical management strategy is needed to 'hold the horses'.…”

“…Deep brain stimulation (DBS) has been shown to have several advantages compared to traditional lesions, including adaptability, reversibility, and the possibility to be performed bilaterally in the same surgical session 3 . The subthalamic nucleus (STN) is the preferred target among centers and is an established and effective form of treatment that improves motor fluctuations, dyskinesia, and quality of life in wellselected patients with PD 4,5 .…”

Jules Bernard Luys: from a description of the subthalamic nucleus to hypnotism

“…Non-motor manifestations are more subtle and less frequent, but may include neuropsychiatric disorders such as hyperphagia, aggressiveness, anxiety, irritability, euphoria, and different types of impulse-control disorders 13,17 . The crucial role of the STN in the pathophysiology of Parkinsonian signs and symptoms results from the fact that dopaminergic neuronal dysfunction induced by degeneration of the substantia nigra leads to STN hyperactivity secondary to dysfunctional dopamine D2 receptor signaling and inhibition of the external globus pallidus (GPe), the main STN inhibitor 13,18,19 . Although levodopa is the main and most effective medication for the treatment of motor symptoms in Parkinson's disease (PD), chronic treatment can be undermined by complications that include motor fluctuations and involuntary hyperkinetic movements (levodopa-induced dyskinesias).…”

Tailoring the deep brain stimulation indications in Parkinson’s disease

“…In this issue of the Journal, Brandão et al 2 highlight the importance of a large, multidisciplinary team of experts to assess potential PD patients as candidates for DBS, and the authors provide a comprehensive overview of current eligibility criteria for the surgery. The classical indications for DBS are based on motor symptoms (refractory motor complications or disabling tremor).…”

“…Recent papers have shown a high response rate in some nonmotor symptoms after DBS (especially pain and sleep), which may be a major determinant for improvement in quality of life 3 . Brandão et al 2 emphasize the importance of a neuropsychological assessment before surgery due to the high prevalence of impulse control disorders in PD patients referred for DBS. It is still controversial whether DBS could worsen or improve impulse control disorders.…”