Movement Disorders and Normal Aging

Normal aging is associated with a variety of changes in the nervous system, many of which manifest as motor impairment. While every effort should be made to determine possible treatable causes for motor decline or involuntary movements in the normal elderly individual, treatment most often will be of a conservative nature, and should include physical therapy or occupational therapy. It should be emphasized that significant neurologic deterioration is not an inevitable aspect of aging. Recent articles and studies have focused on differentiating \ successful\ aging from \ usual\ aging. The challenge for future studies will be to determine those factors that lead to successful aging, thereby allowing clinicians to educate patients on how to achieve optimal health in their later years

Deep Brain Stimulation Amplitude Alters Posture Shift Velocity in Parkinson\u27s Disease

Deep brain stimulation (DBS) of the subtha-lamic nucleus (STN) is now widely used to alleviate symptoms of Parkinson\u27s disease (PD). The specific aim of this study was to identify posture control measures that may be used to improve selection of DBS parameters in the clinic and this was carried out by changing the DBS stimulation amplitude. A dynamic posture shift paradigm was used to assess posture control in 4 PD STN-DBS subjects. Each subject was tested at 4 stimulation amplitude settings. Movements of the center of pressure and the position of the pelvis were monitored and several quantitative indices were calculated. The presence of any statistically significant changes in several normalized indices due to reduced/no stimulation was tested using the one-sample t test. The peak velocity and the average movement velocity during the initial and mid phases of movement towards the target posture were substantially reduced. These results may be explained in terms of increased akinesia and bradykinesia due to altered stimulation conditions. Thus, the dynamic posture shift paradigm may be an effective tool to quantitatively characterize the effects of DBS on posture control and should be further investigated as a tool for selection of DBS parameters in the clinic

Polestriding Intervention Improves Gait and Axial Symptoms in Mild to Moderate Parkinson Disease

Objective To evaluate the effects of 12-week polestriding intervention on gait and disease severity in people with mild to moderate Parkinson disease (PD). Design A-B-A withdrawal study design. Setting Outpatient movement disorder center and community facility. Participants Individuals (N=17; 9 women [53%] and 8 men [47%]; mean age, 63.7±4.9y; range, 53€“72y) with mild to moderate PD according to United Kingdom brain bank criteria with Hoehn & Yahr score ranging from 2.5 to 3.0 with a stable medication regimen and ability to tolerate €œoff€ medication state. Interventions Twelve-week polestriding intervention with 12-week follow-up. Main Outcome Measures Gait was evaluated using several quantitative temporal, spatial, and variability measures. In addition, disease severity was assessed using clinical scales such as Unified Parkinson\u27s Disease Rating Scale (UPDRS), Hoehn & Yahr scale, and Parkinson\u27s Disease Questionnaire-39. Results Step and stride lengths, gait speed, and step-time variability were improved significantly (P\u3c.05) because of 12-week polestriding intervention. Also, the UPDRS motor score, the UPDRS axial score, and the scores of UPDRS subscales on walking and balance improved significantly after the intervention. Conclusions Because increased step-time variability and decreased step and stride lengths are associated with PD severity and an increased risk of falls in PD, the observed improvements suggest that regular practice of polestriding may reduce the risk of falls and improve mobility in people with PD

Discretely scaling a continuous movement: Parkinsons disease patients have more variable movement trajectories

Research suggests that Parkinson\u27s Disease (PD) patients have difficulty scaling the magnitude of their movements. Longstaff et al (2001) showed that patients could continuously scale a drawing movement (spiral) up to a diameter of 5cm like elderly controls, but their trajectories were more variable and there was a smaller distance between each revolution. The present study tests the ability of patients and controls to perform a continuous drawing task with discrete scaling. Subjects were 11 idiopathic PD patients (ages 55 to 81; 8 male, 3 female; Hoehn & Yahr stages 2 and 3; off medication) and 13 elderly controls (ages 62 to 81; 5 male, 6 female). Subjects drew circles on a digitizer matching the size of target circles of diameter 1, 1.5, 2, 3 and 5cm. Five revolutions of each were drawn in the conditions accurate and fast and accurate. Both groups drew circles a similar size, increasing with target size but undershooting the larger circles. Circle size did not change with condition. Both groups drew circles at a similar speed, which was greater in the fast condition. Speed also increased with target size. Both groups increased their variability (radius SD) with increasing target size and in the fast condition, with PD patients having a greater variability than controls in all conditions. This suggests that patients can discretely scale their movements like controls, when needed, but their trajectories are more variable. It is argued that they produce smaller movements partly as a strategy to minimize variability

Movement precues in planning and execution of arm movement in Parkinson\u27s disease

The restructuring of planning processes during movement initiation and execution in 7 persons with Parkinson\u27s disease (PD) off medication was compared to that of 7 older controls. Participants performed a two-stroke aiming movement on a digitizer. From a start position, they passed through a center box to one of two targets located to the left and right of the center box. A precue of the target position was presented prior to the imperative stimulus. In 80% of the trials the precue was correct (valid) and in 20% of the trials the precue was incorrect (invalid). Reaction time (RT), movement time (MT) and the fluency (normalized jerk, NJ) were analyzed. In both groups, RT was significantly longer when the invalid precue was presented. However, RT showed no significant group effect or Group x Precue interaction. In contrast, MT and NJ demonstrated a PD effect. For the first stroke of the two-stroke movement, both MT and NJ showed a significant interaction between Group and Precue. The interactions indicated that in the invalid condition where participants were required to reorganize a planned action, PD patients were substantially slower and produced movements that were considerably less smooth as compared to the valid condition while older controls produced similar MT and NJ in the valid and invalid conditions. Although the execution phase is generally expected to be resistant to restructuring effects, these findings suggest that in PD, restructuring a planned action continues beyond the initiation phase into execution

Intraoperative Test Stimulation Versus Stereotactic Accuracy as a Surgical End Point: A Comparison of Essential Tremor Outcomes After Ventral Intermediate Nucleus Deep Brain Stimulation

OBJECTIVE Ventral intermediate nucleus deep brain stimulation (DBS) for essential tremor is traditionally performed with intraoperative test stimulation and conscious sedation, without general anesthesia (GA). Recently, the authors reported retrospective data on 17 patients undergoing DBS after induction of GA with standardized anatomical coordinates on T1-weighted MRI sequences used for indirect targeting. Here, they compare prospectively collected data from essential tremor patients undergoing DBS both with GA and without GA (non-GA). METHODS Clinical outcomes were prospectively collected at baseline and 3-month follow-up for patients undergoing DBS surgery performed by a single surgeon. Stereotactic, euclidean, and radial errors of lead placement were calculated. Functional (activities of daily living), quality of life (Quality of Life in Essential Tremor [QUEST] questionnaire), and tremor severity outcomes were compared between groups. RESULTS Fifty-six patients underwent surgery: 16 without GA (24 electrodes) and 40 with GA (66 electrodes). The mean baseline functional scores and QUEST summary indices were not different between groups (p = 0.91 and p = 0.59, respectively). Non-GA and GA groups did not differ significantly regarding mean postoperative percentages of functional improvement (non-GA, 47.9% vs GA, 48.1%; p = 0.96) or QUEST summary indices (non-GA, 79.9% vs GA, 74.8%; p = 0.50). Accuracy was comparable between groups (mean radial error 0.9 ± 0.3 mm for non-GA and 0.9 ± 0.4 mm for GA patients) (p = 0.75). The mean euclidean error was also similar between groups (non-GA, 1.1 ± 0.6 mm vs GA, 1.2 ± 0.5 mm; p = 0.92). No patient had an intraoperative complication, and the number of postoperative complications was not different between groups (non-GA, n = 1 vs GA, n = 10; p = 0.16). CONCLUSIONS DBS performed with the patient under GA to treat essential tremor is as safe and effective as traditional DBS surgery with intraoperative test stimulation while the patient is under conscious sedation without GA

Parkinson\u27s Disease Outcomes After Intraoperative CT-Guided Asleep Deep Brain Stimulation in the Globus Pallidus Internus

Objective Recent studies show that deep brain stimulation can be performed safely and accurately without microelectrode recording or test stimulation but with the patient under general anesthesia. The procedure couples techniques for direct anatomical targeting on MRI with intraoperative imaging to verify stereotactic accuracy. However, few authors have examined the clinical outcomes of Parkinson\u27s disease (PD) patients after this procedure. The purpose of this study was to evaluate PD outcomes following \ asleep\ deep brain stimulation in the globus pallidus internus (GPi). methods The authors prospectively examined all consecutive patients with advanced PD who underwent bilateral GPi electrode placement while under general anesthesia. Intraoperative CT was used to assess lead placement accuracy. The primary outcome measure was the change in the off-medication Unified Parkinson\u27s Disease Rating Scale motor score 6 months after surgery. Secondary outcomes included effects on the 39-Item Parkinson\u27s Disease Questionnaire (PDQ-39) scores, on-medication motor scores, and levodopa equivalent daily dose. Lead locations, active contact sites, stimulation parameters, and adverse events were documented. results Thirty-five patients (24 males, 11 females) had a mean age of 61 years at lead implantation. The mean radial error off plan was 0.8 mm. Mean coordinates for the active contact were 21.4 mm lateral, 4.7 mm anterior, and 0.4 mm superior to the midcommissural point. The mean off-medication motor score improved from 48.4 at baseline to 28.9 (40.3% improvement) at 6 months (p \u3c 0.001). The PDQ-39 scores improved (50.3 vs 42.0; p = 0.03), and the levodopa equivalent daily dose was reduced (1207 vs 1035 mg; p = 0.004). There were no significant adverse events. coNclusioNs Globus pallidus internus leads placed with the patient under general anesthesia by using direct anatomical targeting resulted in significantly improved outcomes as measured by the improvement in the off-medication motor score at 6 months after surgery

Functional Ability Correlates With Cognitive Impairment in Parkinson\u27s Disease and Alzheimer\u27s Disease

Background/Aims: Previously we have shown that functional declines in Parkinson\u27s disease (PD) and Alzheimer\u27s disease (AD) correlate to global measures of cognitive decline. We now determine if the correlation between cognitive impairment and functional ability in PD is similar to that in AD using individual cognitive measures. Methods: 93 PD subjects and 124 AD/MCI subjects underwent the Functional Assessment Staging (FAST), the Global Deterioration Scale (GDS), and a neuropsychological battery. Results: In PD subjects, the FAST and GDS correlated significantly with Rey Auditory Verbal Learning Test (AVLT), Controlled Oral Word Association (COWA), Animal Fluency, and Stroop but not with Clock Draw or Judgment Line Orientation (JLO). In AD/MCI subjects, FAST and GDS correlated with all neuropsychological components except Stroop. In the AD/MCI group, the UPDRS significantly correlated with the FAST, GDS, MMSE, and all neuropsychological parameters except the Stroop. In the PD group, the motor UPDRS significantly correlated significantly with FAST, GDS, MMSE and all neuropsychological parameters except Digit Span, Stroop, Clock Draw and JLO. Conclusions: Similar to AD, functional decline in PD correlates with multiple measures of cognitive impairment. Some differences between PD and AD may be explained by the influence of motor disability and declines in visuospatial function in PD