Browsing by Author "Horne, Malcolm"

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    An Ambulatory Tremor Score for Parkinson’s Disease
    (IOS Press, 2016-08) Braybrook, Michelle; O'Connor, Sam; Churchward, Philip; Perera, Thushara; Farzanehfar, Parisa; Horne, Malcolm
    BACKGROUND: While tremor in Parkinson's Disease (PD) can be characterised in the consulting room, its relationship to treatment and fluctuations can be clinically helpful. OBJECTIVE: To develop an ambulatory assessment of tremor of PD. METHODS: Accelerometry data was collected using the Parkinson's KinetiGraph System (PKG, Global Kinetics). An algorithm was developed, which could successfully distinguish been subjects with a resting or postural tremor that involved the wrist whose frequency was greater than 3 Hz. Percent of time that tremor was present (PTT) between 09 : 00 and 18 : 00 was calculated. RESULTS: This algorithm was applied to 85 people with PD who had been assessed clinically for the presence and nature of tremor. The Sensitivity and Selectivity of a PTT >/=0.8% was 92.5% and 92.9% in identifying tremor, providing that the tremor was not a fine kinetic and postural tremor or was not in the upper limb. A PTT >1% provide high likely hood of the presence of clinical meaningful tremor. These cut-offs were retested on a second cohort (n = 87) with a similar outcome. The Sensitivity and Selectivity of the combined group was 88.7% and 89.5% respectively. Using the PTT, 50% of 22 newly diagnosed patients had a PTT >1.0%.The PKG's simultaneous bradykinesia scores was used to find a threshold for the emergence of tremor. Tremor produced artefactual increase in the PKG's dyskinesia score in 1% of this sample. CONCLUSIONS: We propose this as a means of assessing the presence of tremor and its relationship to bradykinesia.
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    At-Home Blood Pressure Measurements Provide Better Assessments of Orthostatic Hypotension in Parkinson's Disease.
    (Journal of Personalized Medicine, 2023-08-28) Fernando, Chathurini V; Osborn, Sarah; Horne, Malcolm
    Orthostatic hypotension (OH) is common in Parkinson's Disease (PD). It is intermittent, exacerbated by stressors including meals, medications, and dehydration, and frequently is unrecognized. Although intermittent, assessment is usually by a single "in clinic" BP measurement. This study examines whether 10 home measurements are more sensitive in detecting OH than a single "in clinic" measurement. Participants (44 people with PD and 16 controls) were instructed to measure lying and standing BP at home. BP was measured on five consecutive days upon waking and before bedtime. Symptoms were also assessed using the Movement Disorder Society United Parkinson's Disease Rating Scale and the Non-Motor Questionnaire. While a postural drop in systolic BP (≥20 mmHg) was recorded "in clinic" in thirteen of the forty-four PD participants, a postural drop was found in at least one of the ten home measurements in twenty-eight of the forty-four participants. Morning hypertension and variability in lying systolic BP was more common in these subjects than in those without a postural drop or the controls. A greater number of measurements of lying and standing BP are more likely to reveal orthostatic hypotension, variation in systolic BP, and hypertension than a single office measurement in people with PD.
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    Minimally invasive endovascular stent-electrode array for high-fidelity, chronic recordings of cortical neural activity
    (Nature Publishing Group, 2016-02-08) Oxley, Thomas; Opie, Nicholas; John, Sam; Rindl, Gil; Ronayne, Stephen; Wheeler, Tracey; Judy, Jack; McDonald, Alan; Dornom, Anthony; Lovell, Timothy; Steward, Christopher; Garrett, David; Moffat, Bradford; Lui, Elaine; Yassi, Nawaf; Campbell, Bruce; Wong, Yan; Fox, Kate; Nurse, Ewan; Bennett, Iwan; Bauquier, Sebastien; Lyanage, Kishan; van de Nagel, Nicole; Perucca, Piero; Ahnood, Arman; Gill, Katherine; Yan, Bernard; Churilov, Leonid; French, Christopher; Desmond, Patricia; Horne, Malcolm; Kiers, Lynette; Prawer, Steven; Davis, Stephen; Burkitt, Anthony; Mitchell, Peter; Grayden, David; May, Clive; O'Brien, Terence
    High-fidelity intracranial electrode arrays for recording and stimulating brain activity have facilitated major advances in the treatment of neurological conditions over the past decade. Traditional arrays require direct implantation into the brain via open craniotomy, which can lead to inflammatory tissue responses, necessitating development of minimally invasive approaches that avoid brain trauma. Here we demonstrate the feasibility of chronically recording brain activity from within a vein using a passive stent-electrode recording array (stentrode). We achieved implantation into a superficial cortical vein overlying the motor cortex via catheter angiography and demonstrate neural recordings in freely moving sheep for up to 190 d. Spectral content and bandwidth of vascular electrocorticography were comparable to those of recordings from epidural surface arrays. Venous internal lumen patency was maintained for the duration of implantation. Stentrodes may have wide ranging applications as a neural interface for treatment of a range of neurological conditions.