Different outcomes of phonemic verbal fluency in Parkinson’s disease patients with subthalamic nucleus deep brain stimulation

Abstract

Subthalamic nucleus deep brain stimulation (STN-DBS) is a surgical technique to treat motor symptoms in patients withParkinson's disease (PD). Studies have shown that STN-DBS may cause a decline in verbal fluency performance. We aimed to verify the effects of STN-DBS on the performance of phonemic verbal fluency in Brazilian PD patients. Sixteen participants were evaluated on the Unified Parkinson's Disease Rating Scale -Part III and for phonemic fluency ("FAS" version) in the conditions of on-and off-stimulation. We identified two different patterns of phonemic verbal fluency outcomes. The results indicate that there may be no expected pattern of effect of bilateral STN-DBS in the phonemic fluency, and patients may present with different outcomes for some reason not well understood.Keywords: Parkinson disease; deep brain stimulation; language; cognition. RESUMOA estimulação cerebral profunda do núcleo subtalâmico (ECP-NST) é uma técnica cirúrgica para tratar sintomas motores na doença de Parkinson (DP). Estudos têm mostrado que ECP-NST pode causar um declínio no desempenho de fluência verbal. O objetivo do estudo foi verificar os efeitos da ECP-NST sobre o desempenho da fluência verbal fonêmica em indivíduos brasileiros com DP. Dezesseis participantes foram avaliados quanto ao desempenho motor (UPDRS-III) e à fluência verbal fonêmica (versão "FAS") nas condições de estimulação ligada e desligada. Identificamos dois padrões diferentes de resultados de fluência verbal fonêmica. Os resultados indicam que pode não haver um padrão esperado de efeito de ECP-NST bilateral na fluência fonêmica, e os pacientes podem apresentar desfechos diferentes de acordo com alguma razão não bem compreendida.Palavras-chave: doença de Parkinson; estimulação encefálica profunda; linguagem; cognição. Subthalamic nucleus deep brain stimulation (STN-DBS)is a procedure used to treat patients with Parkinson's disease (PD) when pharmacological treatment is no longer efficient 1 . It has been proven that DBS suppresses motor symptoms and reduces the total dose of the antiparkinsonian drugs 2,3 . Among the adverse effects of STN-DBS in patients with PD, the postoperative decline in verbal fluency is well documented 4,5,6,7,8,9,10,11 . However, there are fewer studies about the effect of the stimulation per se, comparing on-and off-stimulation conditions 12,13,14 . Longitudinal studies verified a worsening of verbal fluency in the first months after surgery, but an improvement in the later studied months 9 . These authors suggest that this effect of the DBS on the verbal fluency may be due to the micro-lesions caused by the implantation procedure of the electrodes in the STN.The verbal fluency test evaluates the capacity to search and retrieve data stored in long-term memory within a certain category and demonstrates the capacities of

Speech, voice, and language outcomes following deep brain stimulation: A systematic review

“…However, STN-DBS pulse width manipulation did not reveal any significant long-term effects on verbal fluency [113]. However, the findings from studies comparing ON/OFF stimulation are inconsistent, as some studies reporting no significant effects of STN-DBS in this regard [106,109], while others reporting alterations in verbal fluency performance across various stimulation conditions [112,147,153]. There was no consistent timeframe for assessments following deactivation of DBS.…”

Subthalamic Nucleus Stimulation Does Not Have Any Acute Effects on Verbal Fluency or on Speed of Word Generation in Parkinson’s Disease

“…The completion of VF involves accessing and self-generated search of the lexicon requiring a strategy for organizing and clustering the output, the ability to switch between exemplars (cognitive flexibility), self-monitoring and working memory (to avoid repetitions), self-initiation of responses, and inhibition of inappropriate responses. While previous literature suggests that the postsurgical decline in VF in PD is largely a surgical effect and not a stimulation effect (e.g., [8]), nevertheless the results of the studies which have examined the effect of acute STN stimulation on VF in PD are inconsistent, with some studies reporting detrimental effects of high frequency DBS [10–12], others improvement of switching during verbal fluency [13], and the majority of studies finding no such effects [7–9, 14–16]. However, two of the three studies that reported an acute effect of STN-DBS On versus Off manipulation simply examined phonemic VF and not other VF tasks.…”

Pesquisas Envolvendo Pacientes Com Doença De Parkinson No Brasil – Uma Revisão Integrativa

“…Outra complicação possível, é a afecção da fluência verbal (FV), apesar de se acreditar que a redução da FV seja temporária e que ela ocorra mais devido às microlesões durante a cirurgia de implante(ROMANN et al, 2017). Arten e Hamdan(2022) realizaram um estudo onde 63 indivíduos foram divididos em três grupos: o grupo ECP (16 pacientes), grupo medicamentoso (21 pacientes) e o saudáveis (26 pacientes).…”