Directional Stimulation in Parkinson's Disease and Essential Tremor: The Cleveland Clinic Experience.

OBJECTIVE: To assess use of directional stimulation in Parkinson's disease and essential tremor patients programmed in routine clinical care. MATERIALS AND METHODS: Patients with Parkinson's disease or essential tremor implanted at Cleveland Clinic with a directional deep brain stimulation (DBS) system from November 2017 to October 2019 were included in this retrospective case series. Omnidirectional was compared against directional stimulation using therapeutic current strength, therapeutic window percentage, and total electrical energy delivered as outcome variables. RESULTS: Fifty-seven Parkinson's disease patients (36 males) were implanted in the subthalamic nucleus (105 leads) and 33 essential tremor patients (19 males) were implanted in the ventral intermediate nucleus of the thalamus (52 leads). Seventy-four percent of patients with subthalamic stimulation (65% of leads) and 79% of patients with thalamic stimulation (79% of leads) were programmed with directional stimulation for their stable settings. Forty-six percent of subthalamic leads and 69% of thalamic leads were programmed on single segment activation. There was no correlation between the length of microelectrode trajectory through the STN and use of directional stimulation. CONCLUSIONS: Directional programming was more common than omnidirectional programming. Substantial gains in therapeutic current strength, therapeutic window, and total electrical energy were found in subthalamic and thalamic leads programmed on directional stimulation.

Errors in cognitive performance trigger postural instability in Parkinson's disease.

BACKGROUND: Globally, postural stability and cognitive performance are intimately linked in Parkinson's disease (PD). However, a fundamental gap exists in understanding the precise relationship between a disruption in executive function and its impact on postural stability. OBJECTIVE: This project aimed to determine the precise effects of cognitive errors on postural stability under dual-task conditions in participants with PD and controls. METHODS: Twenty-eight individuals with PD and 27 healthy controls completed a series of postural stability tests under single- and dual-tasks. The dual-task required maintenance of balance while performing an audio number discrimination task. RESULTS: In general, postural stability in PD and control subjects was similar across single-task conditions. In controls, an error in the cognitive task during dual-task conditions did not impact measures of postural sway. In contrast, in PD, postural sway increased in epochs surrounding cognitive errors relative to epochs without errors. CONCLUSIONS: Postural task selection plays a critical role when testing for balance deficits in PD compared to healthy controls. Furthermore, time synchronized analysis of cognitive and balance data revealed the greatest episodes of postural instabilities occurred around cognitive errors. The measurement and evaluation of cognitive-motor linkages, relative to postural stability, could provide a patient-specific fingerprint of balance function and provide more sensitive measures for fall risk in PD.

Quantifying turning behavior and gait in Parkinson's disease using mobile technology.

Gait and balance impairments associated with Parkinson's disease (PD) are often refractory to traditional treatments. Objective, quantitative analysis of gait patterns is crucial in successful management of these symptoms. This project aimed to 1) determine if biomechanical metrics from a mobile device inertial measurement unit were sensitive enough to characterize the effects of anti-parkinsonian medication during the Timed Up and Go (TUG) Test, and 2) develop the Cleveland Clinic Mobility and Balance application (CC-MB) to provide clinicians with objective report following completion of the TUG. The CC-MB captured 3-dimensional acceleration and rotational data from people with PD (pwPD) to characterize center of mass movement while performing the TUG. Trials were segmented into four components: Sit-to-Walk, Gait, Turning, and Stand-to-Sit. Thirty pwPD were tested On and Off (12 h) anti-PD medication. Significant improvements (p < 0.05) between On versus Off conditions included: reduction in MDS-UPDRS III motor scores (10.7%), faster trial times (9.3%), more dynamic walking as evident by increased normalized jerk scores (vertical: 17.3%, medial-lateral: 12.3%), shorter turn durations (10.4%), and faster turn velocities (8%). Measures in Sit-to-Walk and Stand-to-Sit did not show significant changes. Trial time and turn velocity showed excellent test-retest reliability (ICC range: 0.83-0.96) across both medication states. A mobile device platform provided quantitative measures of gait and turning during the TUG that detected significant improvements from anti-parkinsonian medications. This platform is a low-cost, easy-to-use tool that can provide objective reports immediately following the clinical assessments, making it ideal for use in and outside the clinical setting.

Normative Performance on the Balance Error Scoring System by Youth, High School, and Collegiate Athletes.

CONTEXT: Annually, more than 1 million youth athletes in the United States receive or are suspected of receiving a concussion. The Balance Error Scoring System (BESS) is the most commonly used clinical balance evaluation designed to provide a better understanding of the motor-control processes of individuals with concussion. Despite the widespread use of the BESS, a fundamental gap exists in applying this tool to young athletes, as normative values are lacking for this population. OBJECTIVE: To determine age- and sex-specific normative values for the BESS in youth, high school, and collegiate athletes. DESIGN: Cross-sectional study. SETTING: Local youth sport organizations, high schools, and colleges. PATIENTS OR OTHER PARTICIPANTS: Student-athletes (N = 6762) completed preseason baseline concussion testing as part of a comprehensive concussion-management program. Groups were youth males aged 5 to 13 years (n = 360), high school males aged 14 to 18 years (n = 3743), collegiate males aged 19 to 23 years (n = 497), youth females aged 5 to 13 years (n = 246), high school females aged 14 to 18 years (n = 1673), and collegiate females aged 19 to 23 years (n = 243). MAIN OUTCOME MEASURE(S): Errors according to the BESS specifications. RESULTS: Performance on the BESS was worse ( P < .01) in youth athletes than in high school and collegiate athletes. In the youth and high school cohorts, females exhibited better scores than males ( P < .05). Sex was not a factor for collegiate athletes. Data from the youth cohort were further subdivided into 4-year bins to evaluate potential motor-development differences. The error count was highest for 5- to 9-year-old males and decreased with age. CONCLUSIONS: Performance on the BESS depended on sex and age, particularly in youth athletes. These sex- and age-specific normative values provide a reference to facilitate and unify clinical decision making across multiple providers caring for youth athletes with concussions.

Cleveland Clinic Postural Stability Index Norms for the Balance Error Scoring System.

INTRODUCTION: Despite the widespread utilization of the Balance Error Scoring System (BESS) in the evaluation of concussion, it has been criticized for its error-based scoring that is susceptible to floor and ceiling effects and substantial inter-rater variability. A biomechanical outcome, Cleveland Clinic Postural Stability Index (CC-PSI), has been developed as an alternative to subjective BESS scoring. The CC-PSI uses inertial sensor data within a mobile device to provide an objective measure of postural sway during the BESS. This project aimed to determine the effect of age and sex on the CC-PSI and report normative values for healthy, active children, adolescents, and young adults. METHODS: A cross-sectional sample of 6762 student-athletes completed BESS testing. Participants were stratified according to three age groups for each sex. The groups included the following: youth (age, 5-13 yr), males (n = 360), females (n = 246); high school (age, 14-18 yr), males (n = 3743), females (n = 1673); and college (age, 19-23 yr), males (n = 497), females (n = 243). Percentile rankings were determined for each participant to characterize movement of COM in the medial-lateral, anterior-posterior, and trunk rotation directions relative to the entire cohort during the BESS stances. RESULTS: Overall, postural stability was worse in youth compared with high school and collegiate athletes. Specifically, the CC-PSI was significantly worse in youth male athletes compared with high school and collegiate male athletes (P < 0.001). Females exhibited significantly better scores compared with males in youth and high school cohorts (P < 0.01). CONCLUSIONS: The CC-PSI provides a quantitative, objective measure of postural stability, overcoming the limitations associated with conventional BESS scoring. Optimal concussion management should use objective age- and sex-specific values in the evaluation of postural stability. The normative values of the CC-PSI may be used in the absence of a baseline BESS evaluation to aid clinical decision making.

Three-dimensional evaluation of postural stability in Parkinson's disease with mobile technology.

BACKGROUND: Postural instability is a hallmark of Parkinson's disease. Objective metrics to characterize postural stability are necessary for the development of treatment algorithms to aid in the clinical setting. OBJECTIVE: The aim of this project was to validate a mobile device platform and resultant three-dimensional balance metric that characterizes postural stability. METHODS: A mobile Application was developed, in which biomechanical data from inertial sensors within a mobile device were processed to characterize movement of center of mass in the medial-lateral, anterior-posterior and trunk rotation directions. Twenty-seven individuals with Parkinson's disease and 27 age-matched controls completed various balance tasks. A postural stability metric quantifying the amplitude (peak-to-peak) of sway acceleration in each movement direction was compared between groups. The peak-to-peak value in each direction for each individual with Parkinson's disease across all trials was expressed as a normalized value of the control data to identify individuals with severe postural instability, termed Cleveland Clinic-Postural Stability Index. RESULTS: In all conditions, the balance metric for peak-to-peak was significantly greater in Parkinson's disease compared to controls (p < 0.01 for all tests). CONCLUSIONS: The balance metric, in conjunction with mobile device sensors, provides a rapid and systematic metric for quantifying postural stability in Parkinson's disease.

Use of Mobile Device Accelerometry to Enhance Evaluation of Postural Instability in Parkinson Disease.

OBJECTIVE: To determine the accuracy of inertial measurement unit data from a mobile device using the mobile device relative to posturography to quantify postural stability in individuals with Parkinson disease (PD). DESIGN: Criterion standard. SETTING: Motor control laboratory at a clinic. PARTICIPANTS: A sample (N=28) of individuals with mild to moderate PD (n=14) and age-matched community-dwelling individuals without PD (n=14) completed the study. INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURES: Center of mass (COM) acceleration measures were compared between the mobile device and the NeuroCom force platform to determine the accuracy of mobile device measurements during performance of the Sensory Organization Test (SOT). Analyses examined test-retest reliability of both systems and sensitivity of (1) the equilibrium score from the SOT and (2) COM acceleration measures from the force platform and mobile device to quantify postural stability across populations. RESULTS: Metrics of COM acceleration from inertial measurement unit data and the NeuroCom force platform were significantly correlated across balance conditions and groups (Pearson r range, .35 to .97). The SOT equilibrium scores failed to discriminate individuals with and without PD. However, the multiplanar measures of COM acceleration from the mobile device exhibited good to excellent reliability across SOT conditions and were able to discriminate individuals with and without PD in conditions with the greatest balance demands. CONCLUSIONS: Metrics employing medial-lateral movement produce a more sensitive outcome than the equilibrium score in identifying postural instability associated with PD. Overall, the output from the mobile device provides an accurate and reliable method of rapidly quantifying balance in individuals with PD. The portable and affordable nature of a mobile device with the application makes it ideally suited to use biomechanical data to aid in clinical decision making.

Objective assessment of postural stability in Parkinson's disease using mobile technology.

BACKGROUND: A significant gap remains in the ability to effectively characterize postural instability in individuals with Parkinson's disease. Clinical evaluation of postural declines is largely subjective, whereas objective biomechanical approaches are expensive and time consuming, thus limiting clinical adoption. Recent advances in mobile devices present an opportunity to address the gap in the quantification of postural stability. The aim of this project was to determine whether kinematic data measured by hardware within a tablet device, a 3rd generation iPad, was of sufficient quantity and quality to characterize postural stability. METHODS: Seventeen patients and 17 age-matched controls completed six balance conditions under altered surface, stance, and vision. Simultaneous kinematic measurements were gathered from a three-dimensional motion capture system and tablet. RESULTS: The motion capture system and tablet provided similar measures of stability across groups. In particular, within the patient population, correlation between the two systems for peak-to-peak, normalized path length, root mean square, 95% volume, and total power values ranged from 0.66 to 1.00. Kinematic data from five balance conditions--double-leg stance with eyes open on a foam surface, double-leg stance with eyes closed on firm and foam surfaces, and tandem stance on firm and foam surfaces--were capable of discriminating patients from controls. CONCLUSIONS: The hardware within the tablet provides data of sufficient accuracy for the quantification of postural stability in patients with Parkinson's disease. The objectivity, portability, and ease of use of this device make it ideal for use in clinical environments lacking sophisticated biomechanical systems.

Quantification of postural stability in older adults using mobile technology.

Traditional biomechanical systems used to capture kinematic data have shown that declines in postural stability are frequently present in older adults and neurological populations. Recent advances in processor speed and measuring capabilities of on-board electronics within mobile devices present an opportunity to gather kinematic data and apply biomechanical analyses to potentially quantify postural stability. The aim of this project was to determine if the kinematic data gathered using a mobile device were of sufficient quantity and quality to characterize postural stability in older adults. Twelve healthy older adults completed six different balance conditions under altered surface, stance and vision. Simultaneous kinematic measurements were gathered from a three-dimensional motion analysis system and iPad during balance conditions. Correlation between the two systems was significant across balance conditions and outcome measures: peak-to-peak (r = 0.70-0.99), normalized path length (r = 0.64-0.98), root mean square (r = 0.73-0.99) of linear acceleration, 95 % volume (r = 0.96-0.99) of linear and angular acceleration and total power across different frequencies (r = 0.79-0.92). The mean absolute percentage error metric, used to evaluate time-series measurements point-by-point, indicated that when measuring linear and angular acceleration, the iPad tracked the motion analysis system with average error between 6 and 10 % of motion analysis measurements across all balance conditions. Collectively, similar accuracy with the iPad compared to motion capture suggests the sensors provide sufficient accuracy and quality for the quantification of postural stability in older adults. The objectivity, portability, and ease of use of this device make it ideal for use in clinical environments, which often lack biomechanical systems.