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Background: Saccade and pupil responses are potential neurodegenerative disease biomarkers due to overlap between oculomotor circuitry and disease-affected areas. Instruction-based tasks have previously been examined as biomarker sources, but are arduous for patients with limited cognitive abilities; additionally, few studies have evaluated multiple neurodegenerative pathologies concurrently. Methods: The Ontario Neurodegenerative Disease Research Initiative recruited individuals with Alzheimer’s disease (AD), mild cognitive impairment (MCI), amyotrophic lateral sclerosis (ALS), frontotemporal dementia, progressive supranuclear palsy, or Parkinson’s disease (PD). Patients (n=274, age 40-86) and healthy controls (n=101, age 55-86) viewed 10 minutes of frequently changing video clips without instruction while their eyes were tracked. We evaluated differences in saccade and pupil parameters (e.g. saccade frequency and amplitude, pupil size, responses to clip changes) between groups. Results: Preliminary data indicates low-level behavioural alterations in multiple disease cohorts: increased centre bias, lower overall saccade rate and reduced saccade amplitude. After clip changes, patient groups generally demonstrated lower saccade rate but higher microsaccade rate following clip change to varying degrees. Additionally, pupil responses were blunted (AD, MCI, ALS) or exaggerated (PD). Conclusions: This task may generate behavioural biomarkers even in cognitively impaired populations. Future work should explore the possible effects of factors such as medication and disease stage.

The purpose of this study was to examine the relationship between lesion location and clinical outcome following globus pallidus internus (GPi) pallidotomy for advanced Parkinson's disease. Thirty-three patients were prospectively studied with extensive neurological examinations before and at 6 and 12 months following microelectrode-guided pallidotomy. Lesion location was characterized using volumetric MRI. The position of lesions within the posteroventral region of the GPi was measured, from anteromedial to posterolateral along an axis parallel to the internal capsule. To relate lesion position to clinical outcome, hierarchical multiple regression analysis was used. The variance in outcome measures that was related to preoperative scores and lesion volume was first calculated, and then the remaining variance attributable to lesion location was determined. Lesion location along the anteromedial-to-posterolateral axis within the GPi influenced the variance in total score on the Unified Parkinson's Disease Rating Scale in the postoperative 'off' period, and in 'on' period dyskinesia scores. Within the posteroventral GPi, anteromedial lesions were associated with greater improvement in 'off' period contralateral rigidity and 'on' period dyskinesia, whereas more centrally located lesions correlated with better postoperative scores of contralateral akinesia and postural instability/gait disturbance. Improvement in contralateral tremor was weakly related to lesions. We conclude that improvement in specific motor signs in Parkinson's disease following pallidotomy is related to lesion position within the posteroventral GPi. These findings are consistent with the known segregated but parallel organization of specific motor circuits in the basal ganglia, and may explain the variability in clinical outcome after pallidotomy and therefore have important therapeutic implications.Keywords:Parkinson's disease; globus pallidus; pallidotomy; clinical outcome

BACKGROUND: Wilson disease (WD) is a rare disorder of copper metabolism.OBJECTIVE: To describe the authors’ clinical experience with a cohort of 48 adult patients followed in an ambulatory setting.METHODS: A retrospective chart review of patients with a diagnosis of WD was performed.RESULTS: Fifty-nine charts were identified and 11 were excluded on further review. At diagnosis, 14 patients were asymptomatic, with 13 hepatic, 15 neurological and six mixed hepatic/neurological presentations. Ceruloplasmin levels were low (<0.20 g/L) in 94%, and 24 h urinary copper levels high (>0.60 µmol/L) in 95% of cases. D-penicillamine was the most common initial therapy (48%), with zinc the most common at review (65%). Overall, biopsy and ultrasound reports documented cirrhosis in 53%. Portal hypertension, defined as splenomegaly (>12.0 cm), reversed portal venous flow on ultrasound or varices/gastropathy on endoscopy was seen in 63%. At last review, 39% had elevated aspartate aminotransferase (>34 U/L) and/or alanine aminotransferase levels (>40 U/L). One death and one transplant occurred, while three patients had encephalopathy, two became jaundiced, two developed ascites and one experienced variceal bleed. Of 21 neurological presenting patients, 14 improved compared with baseline, with four making almost complete recovery. Eleven patients experienced documented episodes of neurological decline, including four with non-neurological presentation. Diagnostic magnetic resonance imaging showed basal ganglia (64%), brainstem (64%) abnormalities and atrophy (36%); follow-up showed basal ganglia lesions (50%) and atrophy (55%).CONCLUSION: WD is a diverse chronic disease with generally favourable outcomes for patients who respond to initial therapy, which can be managed predominantly in an ambulatory setting.