Deficits in sequence-specific learning (SSL) may be a product of Parkinson’s disease (PD) but this deficit could also be related to dopamine replacement. The purpose of this study was to determine whether dopamine replacement affected acquisition and retention of a standing Continuous Tracking Task in individuals with PD. SSL (difference between random/repeated Root Mean Square Error across trials) was calculated over 2 days of practice and 1 day of retention for 4 groups; 10 healthy young (HY), 10 healthy elders, 10 individuals with PD on, 9 individuals with PD off their usual dosage of dopamine replacement. Improvements in acquisition were observed for all groups; however, only the HY demonstrated retention. Therefore, age appeared to have the largest effect on SSL with no significant effect of medication. Additional research is needed to understand the influence of factors such as practice amount, task difficulty, and dopamine replacement status on SSL deficits during postural tasks.
Heather Anne Hayes, Nikelle Hunsaker, Sydney Y. Schaefer, Barry Shultz, Thomas Schenkenberg, Lara A. Boyd, Andrea T. White, Kenneth B. Foreman, Philip Dyer, Rebecca Maletsky and Leland E. Dibble
Anthony D. Mahon, Megan E. Woodruff, Mary P. Horn, Andrea D. Marjerrison and Andrew S. Cole
The effect of stimulant medication use by children with attention deficit/hyper-activity disorder (ADHD) on the rating of perceived exertion (RPE)—heart rate (HR) relationship was examined. Children with ADHD (n = 20; 11.3 ± 1.8 yrs) and children without ADHD (n = 25; 11.2 ± 2.1 yrs) were studied. Children with ADHD were examined while on their usual dose of medication on the day of study. HR and RPE, using the OMNI RPE scale, were assessed during a graded exercise to peak voluntary effort. The RPE-HR relationship was determined individually and the intercept and slope responses were compared between groups. The intercept was 132.4 ± 19.5 bpm for children with ADHD and 120.6 ± 15.7 bpm for children without ADHD. The slope was 7.3 ± 1.9 bpm/RPE for the children with ADHD and 8.1 ± 1.6 bpm/RPE for the children without ADHD. For the group with ADHD the intercept and slope values fell outside of the 95% CI observed in the control group. The altered relationship between RPE and HR with stimulant medication use in children with ADHD has practical implications with respect to the use of HR and RPE to monitor exercise intensity.
Column-editor : Marisa A. Miller
Colleen N. Gulick
Edited by Joe J. Piccininni
Ron Courson, Harris Patel, Lenny Navitskis, Fred Reifsteck and Kelly Ward
Oliver Tucha and Klaus W. Lange
Adverse effects of drug therapy on handwriting fluency attributed to increased attentional control have been observed in children with attention deficit hyperactivity disorder (ADHD). The writing performance of 8 children with ADHD was assessed using a digitizing tablet in a double-blind, placebo-controlled test. Participants wrote a phrase in cursive script both on and off stimulant medication writing normally, writing with eyes closed, and writing faster than normal. Medication reduced fluency of normal handwriting movements. When children with ADHD were instructed to write faster than normal or with eyes closed, however, more fluent and even automated movements resulted, even on medication. We also assessed 10 children with ADHD, 10 children without ADHD, 10 adults with ADHD, and 10 adults without ADHD. Participants with ADHD were assessed both on and off medication. Children with ADHD on medication were less fluent than children without ADHD. Without medication, Children with ADHD did not differ from children without ADHD; those on medication showed increased handwriting dysfluency. There was no significant difference between the adults. Both children and adults with ADHD could perform age-appropriate and automated handwriting movements. Children with ADHD on medication, however, gave more attention to the writing process, possibly hampering fluent handwriting movements.
Douglas W. Powell, Anburaj Muthumani and Ruiping Xia
Bradykinesia is a cardinal symptom of Parkinson’s disease (PD). Both aging and disease are shown to be associated with decreased adaptability to environmental stresses characterized by reduced complexity (or increased regularity) of biorhythms. The purpose of this study was to investigate the regularity of movement in individuals with PD, and the effect of dopaminergic medication. Nine subjects with PD and eight controls performed wrist flexion/extension movements at maximal velocity and range of motion. Subjects with PD were tested under two medication conditions. Approximate entropy (ApEn) was calculated to assess the regularity of the movement, with the smaller value associated with the greater regularity. Data revealed that subjects with PD had lower ApEn values than controls. Medication did not alter the ApEn values. These findings demonstrate that impaired voluntary movement in individuals with PD is associated with increased regularity of movement and this exaggerated regularity appears less sensitive to anti-PD medication.