MyMedR

Determination of the longitudinal validity and minimally important difference of the 8-item Parkinson's Disease Questionnaire (PDQ-8)

Luo N, Tan LC, Zhao Y, Lau PN, Au WL, Li SC

Mov Disord, 2009 Jan 30;24(2):183-7.

PMID: 18972545 DOI: 10.1002/mds.22240

The aim of our study was to assess the longitudinal validity of the 8-item Parkinson's Disease Questionnaire (PDQ-8) in terms of responsiveness and test-retest reliability and to determine the minimally important difference (MID) for PDQ-8 using the anchor-based approach in Asians with Parkinson's disease (PD). A consecutive sample of PD patients attending a tertiary neuroscience clinic in Singapore completed the English or Chinese version of PDQ-8 twice during two different clinic visits. During the second visit, patients were also asked to rate their changes in health in general, PD severity, and overall impact of PD since at the time of their first visit 1 year ago using a 5-point response scale. A total of 96 patients participated in the study. For patients who reported changed conditions in the second visit, responsiveness measured by Cohen's effect size, standardized response mean, and Guyatt's responsiveness index ranged from 0.21 to 0.68. The intraclass correlation coefficient values calculated using patients reporting no change in health or PD status ranged from 0.64 to 0.76. The mean changed PDQ-8 summary index score in patients who reported that their health or PD status worsened only "a little bit" ranged from 5.8 to 7.4 points. Our current results show that PDQ-8 is a longitudinally reliable and responsive measure for assessing the health-related quality of life in patients with PD. The MID of the PDQ-8 estimated in the study will further support the use of this instrument in both clinical research and practice.

Ethnic differences in Singapore's dementia prevalence: the stroke, Parkinson's disease, epilepsy, and dementia in Singapore study

Sahadevan S, Saw SM, Gao W, Tan LC, Chin JJ, Hong CY, et al.

J Am Geriatr Soc, 2008 Nov;56(11):2061-8.

PMID: 19016940 DOI: 10.1111/j.1532-5415.2008.01992.x

To study the prevalence of dementia in Singapore among Chinese, Malays, and Indians.

DYT1 mutations amongst adult primary dystonia patients in Singapore with review of literature comparing East and West

Jamora RD, Tan EK, Liu CP, Kathirvel P, Burgunder JM, Tan LC

J Neurol Sci, 2006 Aug 15;247(1):35-7.

PMID: 16631205

Dystonia is a heterogenous group of movement disorders whose clinical spectrum is very wide. At least 13 different genes and gene loci have been reported. While a 3-bp deletion in the DYT1 gene is the most frequent cause of early limb-onset, generalized dystonia, it has also been found in non-generalized forms of sporadic dystonia. An 18-bp deletion in the DYT1 gene has also been reported.

Prevalence of stroke among Chinese, Malay, and Indian Singaporeans: a community-based tri-racial cross-sectional survey

Venketasubramanian N, Tan LC, Sahadevan S, Chin JJ, Krishnamoorthy ES, Hong CY, et al.

Stroke, 2005 Mar;36(3):551-6.

PMID: 15692124

Stroke prevalence data among mixed Asian populations are lacking. Prevalence rates of stroke were studied among Singaporeans aged > or =50 years of Chinese, Malay, and Indian origin.

Prevalence of Parkinson disease in Singapore: Chinese vs Malays vs Indians

Tan LC, Venketasubramanian N, Hong CY, Sahadevan S, Chin JJ, Krishnamoorthy ES, et al.

Neurology, 2004 Jun 08;62(11):1999-2004.

PMID: 15184604

OBJECTIVE: To investigate the prevalence of Parkinson disease (PD) in Singapore and compare the rates between Singaporean Chinese, Malays, and Indians.

METHODS: A three-phase community-based survey among a disproportionate random sample of 15,000 individuals (9,000 Chinese, 3,000 Malays, 3,000 Indians) aged 50 years and above who live in central Singapore was conducted. In phase 1, trained interviewers conducted a door-to-door survey using a validated 10-question questionnaire. In phase 2, medical specialists examined participants who screened positive to any of the questions. Participants suspected to have PD had their diagnosis confirmed in phase 3 by a movement disorders specialist.

RESULTS: The participation rate was 67% among 22,279 eligible individuals. Forty-six participants with PD were identified of which 16 were newly diagnosed cases. The prevalence rate of PD for those aged 50 and above in Singapore was 0.30% (95% CI: 0.22 to 0.41), age-adjusted to US 1970 census. The prevalence rates increased significantly with age. The age-adjusted prevalence rates among Chinese (0.33%, 95% CI: 0.22 to 0.48), Malays (0.29%, 95% CI: 0.13 to 0.67), and Indians (0.28%, 95% CI: 0.12 to 0.67) were the same (p = 1.0).

CONCLUSIONS: The prevalence of PD in Singapore was comparable to that of Western countries. Race-specific rates were also similar to previously reported rates and similar among the three races. Environmental factors may be more important than racially determined genetic factors in the development of PD.

Asian perspectives on the recognition and management of levodopa 'wearing-off' in Parkinson's disease

Bhidayasiri R, Hattori N, Jeon B, Chen RS, Lee MK, Bajwa JA, et al.

Expert Rev Neurother, 2015;15(11):1285-97.

PMID: 26390066 DOI: 10.1586/14737175.2015.1088783

Most Parkinson's disease patients will receive levodopa therapy, and of these, the majority will develop some levodopa-induced complications. For many patients, the first complication to develop is the decline in the duration of therapeutic benefit of each levodopa dose, a phenomenon commonly termed 'wearing-off'. There is already extensive literature documenting the epidemiology and management of wearing-off in Parkinson's disease patients of western descent. However, data derived from these studies might not always apply to patients of Asian descent due to genetic variations, differences in co-morbidities or non-availability of certain drugs. This review summarizes the current literature regarding the epidemiology of wearing-off in Asian (including Arab) patients and discusses the management issues in the context of drug availability in Asia.

Fulltext Analysis of non-synonymous-coding variants of Parkinson's disease-related pathogenic and susceptibility genes in East Asian populations

Foo JN, Tan LC, Liany H, Koh TH, Irwan ID, Ng YY, et al.

Hum Mol Genet, 2014 Jul 15;23(14):3891-7.

PMID: 24565865 DOI: 10.1093/hmg/ddu086

To evaluate the contribution of non-synonymous-coding variants of known familial and genome-wide association studies (GWAS)-linked genes for Parkinson's disease (PD) to PD risk in the East Asian population, we sequenced all the coding exons of 39 PD-related disease genes and evaluated the accumulation of rare non-synonymous-coding variants in 375 early-onset PD cases and 399 controls. We also genotyped 782 non-synonymous-coding variants of these genes in 710 late-onset PD cases and 9046 population controls. Significant enrichment of LRRK2 variants was observed in both early- and late-onset PD (odds ratio = 1.58; 95% confidence interval = 1.29-1.93; P = 8.05 × 10(-6)). Moderate enrichment was also observed in FGF20, MCCC1, GBA and ITGA8. Half of the rare variants anticipated to cause loss of function of these genes were present in healthy controls. Overall, non-synonymous-coding variants of known familial and GWAS-linked genes appear to make a limited contribution to PD risk, suggesting that clinical sequencing of these genes will provide limited information for risk prediction and molecular diagnosis.

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