RESUMO
People with Parkinson's disease experience reduced sleep quality compared with their peers. Levodopa may have a direct effect on sleep macrostructure or may improve sleep by enhancing nocturnal motor performance. Therefore, it is important to understand the acute effects of withdrawing levodopa on sleep measures in Parkinson's disease. The purpose of this study was to compare the estimated objective and subjective sleep measures of people with Parkinson's disease sleeping under (ON-night) versus without (OFF-night) the effects of the last daily dopaminergic medication before going to bed. A total of 23 people with Parkinson's disease were instructed to wear an actigraphy device for 4 consecutive nights to objectively measure the sleep behaviour. Subjective sleep measure was assessed each morning using a Likert scale. Participants slept for 3â nights on ON-night and 1â night on OFF-night. They were instructed not to take their last dose of levodopa before going to bed in OFF-night. Sleeping in ON- versus OFF-night increased total sleep time (7.8%, p = 0.032) and sleep efficiency (3.7%, p = 0.019), and decreased duration and number of wakes after sleep onset (22.3%, p = 0.050; and 29.2%, p = 0.013, respectively). However, subjective sleep analysis indicated no significant differences between the two conditions. From a clinical point of view, our results suggest that sleeping on ON-night resulted in an improvement in estimated objective sleep measures compared with sleeping on OFF-night. From a methodological point of view, our findings emphasize the importance of relying on objective sleep measurements to accurately assess OFF-night sleep behaviour in people with Parkinson's disease.
RESUMO
PURPOSE: To quantify how postural stability is modified during experimental pain while performing different cognitively demanding tasks. METHODS: Sixteen healthy young adults participated in the experiment. Pain was induced by intramuscular injection of hypertonic saline solution (1 mL, 6%) in both vastus medialis and vastus lateralis muscles (0.9% isotonic saline was used as control). The participants stood barefoot in tandem position for 1 min on a force plate. Center of pressure (CoP) was recorded before and immediately after injections, while performing two cognitive tasks: (i) counting forwards by adding one; (ii) counting backwards by subtracting three. CoP variables-total area of displacement, velocity in anterior-posterior (AP-velocity) and medial-lateral (ML-velocity) directions, and CoP sample entropy in anterior-posterior and medial-lateral directions were displayed as the difference between the values obtained after and before each injection and compared between tasks and injections. RESULTS: CoP total area ( - 84.5 ± 145.5 vs. 28.9 ± 78.5 cm2) and ML-velocity ( - 1.71 ± 2.61 vs. 0.98 ± 1.93 cm/s) decreased after the painful injection vs. Control injection while counting forward (P < 0.05). CoP total area (12.8 ± 53.9 vs. - 84.5 ± 145.5 cm2), ML-velocity ( - 0.34 ± 1.92 vs. - 1.71 ± 2.61 cm/s) and AP-velocity (1.07 ± 2.35 vs. - 0.39 ± 1.82 cm/s) increased while counting backwards vs. forwards after the painful injection (P < 0.05). CONCLUSION: Pain interfered with postural stability according to the type of cognitive task performed, suggesting that pain may occupy cognitive resources, potentially resulting in poorer balance performance.