ORCID Profile
0000-0001-6770-9928
Current Organisation
University of South Australia
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Publisher: Elsevier BV
Date: 04-2015
DOI: 10.1016/J.CLINPH.2014.07.010
Abstract: Restless legs syndrome, now called Willis-Ekbom Disease (RLS/WED), is a sensorimotor-related sleep disorder. Little is known of the effect of RLS/WED on motor function. The current study investigated upper limb function in RLS/WED patients. We hypothesised that RLS/WED patients exhibit subtle changes in tremor litude but normal dexterity and movement speed and rhythmicity compared to healthy controls. RLS/WED patients (n=17, 59 ± 7 years) with moderate disease and healthy controls (n=17, 58 ± 6 years) completed screening tests and five tasks including object manipulation, maximal pinch grip, flexion and extension of the index finger (tremor assessment), maximal finger tapping (movement speed and rhythmicity assessment), and the grooved pegboard test. Force, acceleration, and/or first dorsal interosseus EMG were recorded during four of the tasks. Task performance did not differ between groups. Learning was evident on tasks with repeated trials and the magnitude of learning did not differ between groups. Hand function, tremor, and task learning were unaffected in RLS/WED patients. Patients manipulated objects in a normal manner and exhibited normal movement speed, rhythmicity, and tremor. Further research is needed to assess other types of movement in RLS/WED patients to gain insight into the motor circuitry affected and the underlying pathophysiology.
Publisher: Springer Science and Business Media LLC
Date: 03-05-2014
DOI: 10.1007/S00702-014-1218-Y
Abstract: Abnormal substantia nigra morphology in healthy in iduals, viewed with transcranial ultrasound, is a significant risk factor for Parkinson's disease. However, little is known about the functional consequences of this abnormality (termed 'hyperechogenicity') on movement. The aim of the current study was to investigate hand function in healthy older adults with (SN+) and without (SN-) substantia nigra hyperechogenicity during object manipulation. We hypothesised that SN+ subjects would exhibit increased grip force and a slower rate of force application compared to SN- subjects. Twenty-six healthy older adults (8 SN+ aged 58 ± 8 years, 18 SN- aged 57 ± 6 years) were asked to grip and lift a light-weight object with the dominant hand. Horizontal grip force, vertical lift force, acceleration, and first dorsal interosseus EMG were recorded during three trials. During the first trial, SN+ subjects exhibited a longer period between grip onset and lift onset (i.e. preload duration 0.27 ± 0.25 s) than SN- subjects (0.13 ± 0.08 s P = 0.046). They also exerted a greater downward force prior to lift off (-0.54 ± 0.42 N vs. -0.21 ± 0.12 N P = 0.005) and used a greater grip force to lift the object (19.5 ± 7.0 N vs. 14.0 ± 4.3 N P = 0.022) than SN- subjects. No between group differences were observed in subsequent trials. SN+ subjects exhibit impaired planning for manipulation of new objects. SN+ in iduals over-estimate the grip force required, despite a longer contact period prior to lifting the object. The pattern of impairment observed in SN+ subjects shares similarities with de novo Parkinson's disease patients.
Publisher: Elsevier BV
Date: 12-2019
DOI: 10.1016/J.DRUGALCDEP.2019.107595
Abstract: Illicit stimulant use is associated with long-lasting changes in movement and movement-related brain regions. The aim of our study was to investigate the prevalence of movement dysfunction in this population. We hypothesized that prevalence of self-reported movement dysfunction is higher among stimulant users than non-stimulant users. Three groups of adults completed a survey containing questions about demographics, health, drug use, and movement. The groups consisted of ecstasy users with no history of meth hetamine use (ecstasy group, n = 190, 20 ± 3 yrs.), meth hetamine users (meth hetamine group, n = 331, 23 ± 5 yrs.), and non-stimulant users (control group, n = 228, 25 ± 8 yrs.). Movement data was analyzed with logistic regression. In the unadjusted logistic regression model, group had a significant effect on fine hand control, tremor, and voice/speech questions, but not on other movement domain questions. The prevalence of tremor and abnormal fine hand control was significantly higher in the ecstasy and meth hetamine groups than in the control group (p < 0.018), and changes in voice/speech was more prevalent in the ecstasy group than in the control group (p = 0.015). Age and use of cannabis and hallucinogens were confounding variables. However, inspection of chi-square tables suggests that the effect of these parameters on the movement data is likely to be minor. The prevalence of self-reported tremor and changes in fine hand control and voice/speech is significantly higher in stimulant users than in non-stimulant users. Inclusion of these common and noticeable changes in body function may aid public health c aigns that target prevention or harm minimization.
Publisher: Elsevier BV
Date: 12-2020
Publisher: Elsevier BV
Date: 05-2019
DOI: 10.1016/J.CLINPH.2019.02.005
Abstract: The study aim was to determine if use of illicit hetamines or ecstasy is associated with abnormal excitability of the corticomotoneuronal pathway and manipulation of novel objects with the hand. Three groups of adults aged 18-50 years were investigated: in iduals with a history of illicit hetamine use, in iduals with a history of ecstasy use but minimal use of other stimulants, and non-drug users. Transcranial magnetic stimulation was delivered to the motor cortex and the electromyographic response (motor evoked potential MEP) was recorded from a contralateral hand muscle. Participants also gripped and lifted a novel experimental object consisting of two strain gauges and an accelerometer. Resting MEP litude was larger in the hetamine group (6M, 6F) than the non-drug and ecstasy groups (p < 0.005) in males but not females. Overestimation of grip force during manipulation of a novel object was observed in the hetamine group (p = 0.020) but not the ecstasy group. History of illicit hetamine use, in particular meth hetamine, is associated with abnormal motor cortical and/or corticomotoneuronal excitability in males and abnormal manipulation of novel objects in both males and females. Abnormal excitability and hand function is evident months to years after cessation of illicit hetamine use.
No related grants have been discovered for Patrick Faulkner.