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Research paper thumbnail of Levodopa ONOFF-state freezing of gait: Defining the gait and non-motor phenotype

PLOS ONE

Background Freezing in the levodopa-medicated-state (ON-state) is a debilitating feature of Parki... more Background Freezing in the levodopa-medicated-state (ON-state) is a debilitating feature of Parkinson’s disease without treatment options. Studies detailing the distinguishing features between people with freezing of gait that improves with levodopa and those whose freezing continues even on levodopa are lacking. Objective To characterize the gross motor, gait, and non-motor features of this phenotype. Methods Instrumented continuous gait was collected in the levodopa-medicated-state in 105 patients: 43 non-freezers (no-FOG), 36 with freezing only OFF-levodopa (OFF-FOG) and 26 with freezing both ON- and OFF-levodopa (ONOFF-FOG). Evaluation of motor and non-motor disease features was undertaken using validated scales. A linear mixed model with age, sex, disease duration, and motor UPDRS scores as covariates was used to determine differences in spatiotemporal gait and non-motor disease features among the groups. Results Compared to OFF-FOG, the ONOFF-FOG group had greater disease seve...

Research paper thumbnail of Impaired step-length setting prior to turning in Parkinson's disease patients with freezing of gait

Movement disorders : official journal of the Movement Disorder Society, Jan 10, 2018

Impaired stride-length setting is implicated in the development of freezing of gait (FOG) in PD, ... more Impaired stride-length setting is implicated in the development of freezing of gait (FOG) in PD, with reduced mean step-length superimposed on a successively reduced step-length (sequence effect) leading to freezing episodes. 1 The majority of PD patients note FOG during gait initiation and/or turning. 2 While the first three steps on gait initiation were shorter in FOG subjects, 3 successively reduced step-length prior to turning has not been directly demonstrated. Our goal was to determine if prior to a turn, step-length setting was differentially affected in PD FOG patients.

Research paper thumbnail of Increased foot strike variability in Parkinson's disease patients with freezing of gait

Parkinsonism & related disorders, 2018

Freezing of gait (FOG) is a debilitating, late motor complication of Parkinson's disease (PD)... more Freezing of gait (FOG) is a debilitating, late motor complication of Parkinson's disease (PD) that occurs in 50-80% of patients. Gait freezing significantly worsens quality of life by decreasing mobility and increasing falls. Studies have shown that patients with episodic freezing episodes also have deficits in continuous gait. We evaluated whether there was an objective gait correlate to the increased stumbling reported by many patients with gait freezing. PD subjects and healthy controls (HC) were enrolled after IRB approval. Subjects with more than 1 fall/day or a Montreal Cognitive Assessment score <10 were excluded. Subjects walked at their normal pace, 8 lengths of a 20 × 4 foot pressure-sensor mat. Data was collected and analyzed using PKMAS software (Protokinetics) and statistical analysis performed using SPSS 22 (IBM). 72 age matched subjects (22 PD FOG, 27 PD no-FOG, and 23 HC) were enrolled. Disease duration and Hoehn & Yahr scores were not significantly different ...

Research paper thumbnail of Differential Gait Decline in Parkinson’s Disease Enhances Discrimination of Gait Freezers from Non-Freezers

Journal of Parkinson's Disease, 2020

Background: Freezing of gait (FOG) is a debilitating feature of Parkinson’s disease (PD) for whic... more Background: Freezing of gait (FOG) is a debilitating feature of Parkinson’s disease (PD) for which treatments are limited. To develop neuroprotective strategies, determining whether disease progression is different in phenotypic variants of PD is essential. Objective: To determine if freezers have a faster decline in spatiotemporal gait parameters. Methods: Subjects were enrolled in a longitudinal study and assessed every 3– 6 months. Continuous gait in the levodopa ON-state was collected using a gait mat (Protokinetics). The slope of change/year in spatiotemporal gait parameters was calculated. Results: 26 freezers, 31 non-freezers, and 25 controls completed an average of 6 visits over 28 months. Freezers had a faster decline in mean stride-length, stride-velocity, swing-%, single-support-%, and variability in single-support-% compared to non-freezers (p < 0.05). Gait decline was not correlated with initial levodopa dose, duration of levodopa therapy, change in levodopa dose or ...

Research paper thumbnail of Levodopa ONOFF-state freezing of gait: Defining the gait and non-motor phenotype

PLOS ONE

Background Freezing in the levodopa-medicated-state (ON-state) is a debilitating feature of Parki... more Background Freezing in the levodopa-medicated-state (ON-state) is a debilitating feature of Parkinson’s disease without treatment options. Studies detailing the distinguishing features between people with freezing of gait that improves with levodopa and those whose freezing continues even on levodopa are lacking. Objective To characterize the gross motor, gait, and non-motor features of this phenotype. Methods Instrumented continuous gait was collected in the levodopa-medicated-state in 105 patients: 43 non-freezers (no-FOG), 36 with freezing only OFF-levodopa (OFF-FOG) and 26 with freezing both ON- and OFF-levodopa (ONOFF-FOG). Evaluation of motor and non-motor disease features was undertaken using validated scales. A linear mixed model with age, sex, disease duration, and motor UPDRS scores as covariates was used to determine differences in spatiotemporal gait and non-motor disease features among the groups. Results Compared to OFF-FOG, the ONOFF-FOG group had greater disease seve...

Research paper thumbnail of Impaired step-length setting prior to turning in Parkinson's disease patients with freezing of gait

Movement disorders : official journal of the Movement Disorder Society, Jan 10, 2018

Impaired stride-length setting is implicated in the development of freezing of gait (FOG) in PD, ... more Impaired stride-length setting is implicated in the development of freezing of gait (FOG) in PD, with reduced mean step-length superimposed on a successively reduced step-length (sequence effect) leading to freezing episodes. 1 The majority of PD patients note FOG during gait initiation and/or turning. 2 While the first three steps on gait initiation were shorter in FOG subjects, 3 successively reduced step-length prior to turning has not been directly demonstrated. Our goal was to determine if prior to a turn, step-length setting was differentially affected in PD FOG patients.

Research paper thumbnail of Increased foot strike variability in Parkinson's disease patients with freezing of gait

Parkinsonism & related disorders, 2018

Freezing of gait (FOG) is a debilitating, late motor complication of Parkinson's disease (PD)... more Freezing of gait (FOG) is a debilitating, late motor complication of Parkinson's disease (PD) that occurs in 50-80% of patients. Gait freezing significantly worsens quality of life by decreasing mobility and increasing falls. Studies have shown that patients with episodic freezing episodes also have deficits in continuous gait. We evaluated whether there was an objective gait correlate to the increased stumbling reported by many patients with gait freezing. PD subjects and healthy controls (HC) were enrolled after IRB approval. Subjects with more than 1 fall/day or a Montreal Cognitive Assessment score <10 were excluded. Subjects walked at their normal pace, 8 lengths of a 20 × 4 foot pressure-sensor mat. Data was collected and analyzed using PKMAS software (Protokinetics) and statistical analysis performed using SPSS 22 (IBM). 72 age matched subjects (22 PD FOG, 27 PD no-FOG, and 23 HC) were enrolled. Disease duration and Hoehn & Yahr scores were not significantly different ...

Research paper thumbnail of Differential Gait Decline in Parkinson’s Disease Enhances Discrimination of Gait Freezers from Non-Freezers

Journal of Parkinson's Disease, 2020

Background: Freezing of gait (FOG) is a debilitating feature of Parkinson’s disease (PD) for whic... more Background: Freezing of gait (FOG) is a debilitating feature of Parkinson’s disease (PD) for which treatments are limited. To develop neuroprotective strategies, determining whether disease progression is different in phenotypic variants of PD is essential. Objective: To determine if freezers have a faster decline in spatiotemporal gait parameters. Methods: Subjects were enrolled in a longitudinal study and assessed every 3– 6 months. Continuous gait in the levodopa ON-state was collected using a gait mat (Protokinetics). The slope of change/year in spatiotemporal gait parameters was calculated. Results: 26 freezers, 31 non-freezers, and 25 controls completed an average of 6 visits over 28 months. Freezers had a faster decline in mean stride-length, stride-velocity, swing-%, single-support-%, and variability in single-support-% compared to non-freezers (p < 0.05). Gait decline was not correlated with initial levodopa dose, duration of levodopa therapy, change in levodopa dose or ...