Jonas Yeung

Alice Ho Miu Ling Nethersole Hospital, Ch’üan-wan, Tsuen Wan, Hong Kong

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Publications (11)52.83 Total impact

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    ABSTRACT: The present study investigated the neuropsychological effects of bilateral deep brain stimulation (DBS) on subthalamic nucleus (STN) in Chinese-Cantonese patients with idiopathic Parkinson's disease (PD). Twenty-seven patients were prospectively recruited from the Movement Disorder Clinic at the Hong Kong Prince of Wales Hospital. Neuropsychological evaluations were performed at baseline, 6 and 12 months following the DBS procedure. Assessment battery included standardized tests on global cognitive function, verbal memory, non-verbal memory, confrontation naming, visuospatial organization, attention and executive functions. Anxiety and depressive symptoms were measured by two self-reported questionnaires. Results demonstrated diminished performance on a category fluency task that occurred at 6 months post-operatively and persisted at 12-month re-evaluation; 29.6-33.3 % of patients showed reduction of more than 1 SD (standard deviation) at post-operative measure. Conversely, performance on an immediate recall task in a verbal memory test was found to improve significantly at the same time point and persisted through 12 months after surgery; 22.2-25.9 % showed an improvement (≥1 SD). Psychologically, anxiety symptoms were statistically decreased and the significant reduction occurred at 12 months after surgery. Patients who reported a moderate to severe level of anxiety reduced from 51.9 to 18.5 %. Our findings concurred with most evidences on the effects of STN-DBS on verbal fluency; on the other hand, we demonstrated improvement of immediate verbal memory that warranted further investigation.
    Full-text · Article · Feb 2015 · Neurological Sciences
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    ABSTRACT: OBJECTIVE. To present the result and experience of subthalamic nucleus deep brain stimulation for Parkinson's disease. DESIGN. Case series. SETTING. Prince of Wales Hospital, Hong Kong. PATIENTS. A cohort of patients with Parkinson's disease received subthalamic nucleus deep brain stimulation from September 1998 to January 2010. Patient assessment data before and after the operation were collected prospectively. RESULTS. Forty-one patients (21 male and 20 female) with Parkinson's disease underwent bilateral subthalamic nucleus deep brain stimulation and were followed for a median interval of 12 months. For the whole group, the mean improvements of Unified Parkinson's Disease Rating Scale (UPDRS) parts II and III were 32.5% and 31.5%, respectively (P<0.001). Throughout the years, a multidisciplinary team was gradually built. The deep brain stimulation protocol evolved and was substantiated by updated patient selection criteria and outcome assessment, integrated imaging and neurophysiological targeting, refinement of surgical technique as well as the accumulation of experience in deep brain stimulation programming. Most of the structural improvement occurred before mid-2005. Patients receiving the operation before June 2005 (19 cases) and after (22 cases) were compared. The improvements in UPDRS part III were 13.2% and 55.2%, respectively (P<0.001). There were three operative complications (one lead migration, one cerebral haematoma, and one infection) in the group operated before 2005. There was no operative mortality. CONCLUSIONS. The functional state of Parkinson's disease patients with motor disabilities refractory to best medical treatment improved significantly after subthalamic nucleus deep brain stimulation. A dedicated multidisciplinary team building, refined protocol for patient selection and assessment, improvement of targeting methods, meticulous surgical technique, and experience in programming are the key factors contributing to the improved outcome.
    Full-text · Article · Oct 2014 · Hong Kong medical journal = Xianggang yi xue za zhi / Hong Kong Academy of Medicine
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    ABSTRACT: Tardive dystonia is an iatrogenic complication of dopamine receptor antagonist medication such as first-generation antipsychotics. It occurs in up to 2% of patients and only 10% recover after stopping medication. Deep brain stimulation for primary dystonia has proven to be effective and its application for secondary dystonias is gaining acceptance. We report our experience in treating three ethnic Chinese schizophrenia patients with severe medically refractory tardive dystonia by globus pallidus internus deep brain stimulation. Preoperatively, all required assistance with essential activities of daily living and two were bed-bound. The mean Burke-Fahn-Marsden Dystonia Rating Scale score was 61 (range, 44-80) and mean Global Dystonia Rating Scale score was 47 (range, 40-52). No procedure-related complications were encountered. By 3 months all could return to unassisted living and walk with support with a mean of 77% and 66% improvement in the Burke-Fahn-Marsden Dystonia Rating Scale and Global Dystonia Rating Scale scores, respectively. Quality-of-life assessment performed for two patients using the EuroQol-5 dimensions visual analogue scale showed a mean improvement of 86% at 3 months. On clinical follow-up, the effect was well maintained for a period of 3 to 10 years. Pallidal deep brain stimulation is a safe and highly effective form of symptomatic treatment for patients with medically refractory tardive dystonia.
    No preview · Article · Oct 2014 · Hong Kong medical journal = Xianggang yi xue za zhi / Hong Kong Academy of Medicine
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    ABSTRACT: Deep brain stimulation (DBS) is an effective but costly treatment for advanced Parkinson's disease (PD). This study examined the cost-effectiveness of DBS in relation to its improved effectiveness, in order to help funding decision makers decide whether the treatment should be adopted. The incremental cost-effective ratio (ICER) per quality-adjusted life year (QALY) has been benchmarked as being between US$50,000 and US$100,000 by the United States agencies, whereas it is under €30,000 per QALY in Europe.
    Full-text · Article · Aug 2014 · World Neurosurgery
  • C.A. Graham · T.H. Rainer · J.H. Yeung · W.S. Poon

    No preview · Article · Oct 2012 · Annals of Emergency Medicine
  • C.A. Graham · T.H. Rainer · J.H. Yeung · W.S. Poon

    No preview · Article · Oct 2012 · Annals of Emergency Medicine
  • Claudia Ky Lai · Jonas Hm Yeung · Vincent Mok · Iris Chi
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    ABSTRACT: There is limited evidence to support the assumption that the care of people with dementia in special care units (SCUs) is superior to care in traditional nursing units. No randomized controlled trials (RCTs) can be found comparing the effect of SCUs against traditional nursing units in managing agitated behaviours in people suffering from dementia. This review has examined the results of non-RCTs. The findings about the outcomes of this review arise just from one study except for the outcome of "physical restraint use" at 6 months, which includes data from two studies. Selection bias is a major problem in non-RCTs, and confounds the limited evidence that favoured SCU care with regard to a decrease in agitated behaviour and in the use of physical restraints. A convincing case for the benefits of SCU care cannot be made and further studies are necessary.
    No preview · Article · Oct 2009 · Cochrane database of systematic reviews (Online)
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    ABSTRACT: The frequency of LRRK2 Gly2385Arg mutation in Hong Kong Chinese with early-onset (age < or =45 years) Parkinson's disease was identified and compared with late-onset patients (age >50 years) and controls. The mutation prevalence were 8.8, 8.3, and 0% for early-onset, late-onset, and controls, respectively. The mean age of onset among LRRK2 G2385R carriers was 42.7 years old for early-onset compared to 74.3 for late-onset patients. LRRK2 G2385R mutation appears to be as prevalent among early-onset as late-onset patients.
    No preview · Article · Sep 2008 · Journal of Neural Transmission
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    ABSTRACT: Our aim was to characterise PARK2 mutations and clinical features in Hong Kong Chinese with early-onset Parkinson's disease. Subjects were recruited from two major hospitals. Detailed data included demographics, age of onset, duration of disease, neurological manifestations, complications and disease severity. Genetic analysis for PARK2 mutations was performed. Thirty-four patients were recruited (mean age of onset = 39 years; mean duration of disease = 10 years). Seven patients reported a family history. The salient clinical manifestations were resting tremor (33/34), bradykinesia (33/34), rigidity (30/34), postural instability (20/34), good response to L-dopa (33/34), asymmetry at onset (31/34) and sleep benefit (12/34). Motor complications were reported in a significant number of patients, and depression was the most common nonmotor complication. Five patients were identified to have PARK2 mutations. Two sisters were compound heterozygotes for an insertion and a deletion, a novel and rare 1 bp insertion/nonsense mutation c1378_1379insG (exon 12) and the entire deletion of exon 7. Another patient was homozygous for the entire deletion of exon 6. Two carriers were identified, one with a T1321C (Cys441Arg) missense mutation in exon 12 and another with a snp within intron 4. Our study reviewed a higher prevalence of PARK2 mutations in Chinese than that previously documented. A compound heterozygous mutation within two sisters with significant differences in age of onset and phenotypic manifestations suggest that modifier affects may be present in this family.
    No preview · Article · Jun 2008 · Journal of Neural Transmission

  • No preview · Article · Apr 2008 · Annals of Emergency Medicine
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    ABSTRACT: Acute stroke patients with large artery occlusive disease (LAOD) have a distinct pathophysiology and may respond differently to anticoagulation treatments. We compared the efficacy of a low-molecular-weight heparin (LMWH), nadroparin calcium, with aspirin in Asian acute stroke patients with LAOD. Acute ischaemic stroke patients with onset of symptoms less than 48 h and LAOD (diagnosed by transcranial doppler imaging, carotid duplex scan, or magnetic resonance angiography) were recruited. Patients were randomly assigned to receive either subcutaneous nadroparin calcium 3800 anti-factor Xa IU/0.4 mL twice daily or oral aspirin 160 mg daily for 10 days, and then all received aspirin 80-300 mg once daily for 6 months. This study is registered at www.strokecenter.org/trials (number 493). Among 603 patients recruited, 353 (180 LMWH, 173 aspirin) had LAOD (300 had intracranial LAOD only, 42 had both intracranial and extracranial disease, and 11 had extracranial disease only). The proportion of patients with good outcomes at 6 months (Barthel index >or=85) was 73% in the LMWH group and 69% in the aspirin group (absolute risk reduction 4%; 95% CI -5 to 13). Analysis of prespecified secondary outcome measures showed a benefit in outcome for LMWH versus aspirin on the modified Rankin scale dichotomised at 0-1 (odds ratio 1.55, 95% CI 1.02-2.35). Haemorrhagic transformation of infarct and severe adverse events were similar in both groups. Post-hoc analyses of patients without LAOD, and all treated patients, showed similar proportions with a good outcome in aspirin and LMWH groups (78%vs 79% and 73%vs 75%, respectively). Overall, the results do not support a significant benefit of LMWH over aspirin in patients with LAOD. The benefits indicated in most outcome measures warrant further investigation into the use of anticoagulation for acute stroke in patients with large artery atherosclerosis, particularly in intracranial atherosclerosis.
    No preview · Article · May 2007 · The Lancet Neurology