Proficient motor impulse control in Parkinson disease patients with impulsive and compulsive behaviors

Abstract

Background Parkinson Disease (PD) patients treated with Dopamine Agonist therapy can develop maladaptive reward-driven behaviors, known as Impulse Control Disorder (ICD). In this study, we assessed if ICD patients have evidence of motor-impulsivity. Methods We used the stop-signal task in a cohort of patients with and without active symptoms of ICD to evaluate motor-impulsivity. Of those with PD, 12 were diagnosed with ICD symptoms (PD-ICD) and were assessed before clinical reduction of Dopamine Agonist medication; 12 were without symptoms of ICD [PD-control] and taking equivalent dosages of Dopamine Agonist. Levodopa, if present, was maintained in both settings. Groups were similar in age, duration, and severity of motor symptoms, levodopa co-therapy, and total levodopa daily dose. All were tested in the Dopamine Agonist medicated and acutely withdrawn (24 hours) state, in a counterbalanced manner. Primary outcome measures were mean reaction time to correct go trials (Go Reaction Time), and mean stop-signal reaction time (SSRT). Results ICD patients produce faster SSRT than both Healthy Controls, and PD Controls. Faster SSRT in ICD patients is apparent in both Dopamine Agonist medication states. Also, we show unique dopamine medication effects on GoRT. In Dopamine Agonist monotherapy patients, Dopamine Agonist administration speeds Go Reaction Time. Conversely, in those with levodopa co-therapy, Dopamine Agonist administration slows Go Reaction Time. Discussion PD patients with active ICD symptoms are significantly faster at stopping initiated motor actions, and this is not altered by acute Dopamine Agonist withdrawal. In addition, the effect of Dopamine Agonist on Go Reaction Time is strongly influenced by the presence or absence of levodopa, even though levodopa co-therapy does not appear to influence SSRT. We discuss these findings as they pertain to the multifaceted definition of ‘impulsivity,’ the lack of evidence for motor-impulsivity in PD-ICD, and dopamine effects on motor-control in PD.

Influence of promised rewards on conflict resolution in healthy participants and patients with Parkinson's disease

“…However, when selective suppression became effective (second slope), there ceased to be a difference in suppression efficiency between the two groups. This lack of a significant difference in the second part of the distribution contrasts with previous studies showing that patients with PD have impaired impulse suppression even when they respond slowly enough to allow the suppression process to get going [30,31,[37][38][39][40][41]. This difference can be explained by the fact that we estimated the temporal dynamics of the responses with only three bins, compared with between five and seven bins in the above-cited studies, leading to a less accurate representation of response distribution.…”

Impulse control disorders and levodopa-induced dyskinesias in Parkinson's disease: an update

“…Pramipexole increased waiting impulsivity and impulsive action both in sham and lesioned rats but its effect on waiting impulsivity in lesioned rats was enhanced in animals with pre-existing impulsivity traits 105 . However, in contrast to impairments in decisional impulsivity in humans, studies either did not detect impairments 93 or showed improvement 106 in motor response inhibition in PD+ICD subjects tested using the stop signal task. Contrasting with ICDs, PD patients with LID display altered motor inhibition, as shown with decreased reaction time during erroneous stop trials 107 .…”

Impulse Control Disorder in Parkinson's Disease: A Meta-Analysis of Cognitive, Affective, and Motivational Correlates

“…Finally, a single study reported better executive functions in ICD+ ( 24 ). Reports on affective factors are also inconclusive, as self-reported depression and anxiety were sometimes found to be associated with ICD ( 18 , 20 , 21 , 25 – 28 ), and sometimes not ( 3 – 6 , 17 , 19 , 22 , 29 – 31 ). However, motivational factors such as self-reported apathy ( 11 , 21 , 27 , 28 ), anhedonia ( 27 , 32 ), and impulsivity ( 17 , 20 – 22 , 32 ) appeared to be elevated in ICD+ vs. ICD–.…”