Prescribing pattern in Parkinson's disease: are cost and efficacy overriding factors?

Information on prescribing pattern of antiparkinsonian medications and factors influencing neurologists' choice of such drugs are important considerations in evaluating healthcare cost of Parkinson's disease (PD). We surveyed neurologists' perceived factors influencing their choice of drugs and actual prescribing pattern in PD. Three hundred and six patients at a tertiary hospital, diagnosed with idiopathic PD and who were dispensed antiparkinsonian drugs during a 6-month period were randomly selected. Patient demographics, type and dose of medications were analysed. A questionnaire survey evaluating the factors influencing choice of medications was administered to neurologists who practiced at the institution. The study population had a mean age of 64.4 years (SD +/- 9.9 years), and more than 80% were at Hoehn & Yahr stage 2-3. 92.3% of the study population were receiving levodopa and monotherapy, with levodopa being the most common treatment regimen. Patients who were prescribed levodopa were significantly older and at a later stage of disease compared to those without levodopa (p < 0.05). Only 26.8% of patients were prescribed dopamine agonists. In the survey, the neurologists cited severity of symptoms, and patients' intolerance of side effects, and efficacy as the most important factors influencing their choice of drugs. However, the actual prescribing pattern revealed a strong positive correlation of drug usage with cost subsidy by the institution. While factors affecting drug usage in PD are well recognised, cost and efficacy of a drug appear to be overriding practical factors in influencing usage pattern in clinical practice.     

Transcranial magnetic stimulation screening for cord compression in cervical spondylosis

OBJECTIVE: Cervical spondylosis (CS) often results in various degrees of cord compression, which can be evaluated functionally with transcranial magnetic stimulation (TMS). We investigate the use of TMS as a screening tool for myelopathy in CS. METHODS: We prospectively studied 231 patients classified into Groups 1 to 4 based on MRI grading of severity of cord compromise. TMS elicited central motor conduction times and motor evoked potential (MEP) amplitudes in all 4 limbs. The results were compared with those from 45 healthy controls. RESULTS: TMS showed 98% sensitivity and 98% specificity for cord abnormality using MRI as reference standard. CONCLUSIONS: MEP abnormalities are useful for electrophysiological evaluation of cord compression in CS. While TMS is not a substitute for MRI, it is of value as a rapid, inexpensive and non-invasive technique for screening patients before MRI studies.     

Nurr1 mutational screen in Parkinson's disease.

We performed sequence analysis of all the exons and exon-intron boundaries in familial and young-onset Parkinson's disease (PD) in an Asian cohort. None of the patients carried any pathogenic mutations in the Nurr1 gene. We demonstrated a 5 to 10% prevalence of the intron 7 +33 C-->T variant among Malay and Indian PD and healthy controls, suggesting that this variant, which was previously described only in 1 Chinese patient, was not a silent mutation but a common polymorphic variant in some ethnic races.     

An urge to move with L-thyroxine: clinical, biochemical, and polysomnographic correlation.

We report on the cause and effect relationship of restless legs syndrome (RLS) with L-thyroxine treatment in a hypothyroid patient with low serum ferritin. Upon challenge and withdrawal of L-thyroxine, there was a significant change in the International Restless Legs Syndrome Study Group severity score (26/40 to 6/40), the periodic limb movements (PMLS) index (20/hour to 10/hour), the number of arousals due to PLMS (59 to 22), sleep efficiency (74 to 85%), and biochemical parameters. RLS symptoms can complicate thyroxine replacement in at-risk hypothyroid patients with low serum ferritin. Early diagnosis and iron replacement could significantly reduce patient morbidity.     

Analysis of LRRK2 functional domains in nondominant Parkinson disease

A comprehensive sequence analysis of 29 exons that code for the functional domains of LRRK2 in 160 nondominant Parkinson disease (PD) patients was performed. Novel variant screening in a further 470 sporadic PD patients and 630 controls revealed two novel variants (R1067Q and IVS33 + 6 T>A), which are likely to be pathogenic in five patients. One patient presented initially with a typical essential tremor phenotype, expanding the phenotypic spectrum of LRRK2 mutations.     

Genetic analysis of DJ-1 in a cohort Parkinson's disease patients of different ethnicity

Mutations in the DJ-1 gene have been described in autosomal recessive Parkinson's disease patients (ARPD) of European ancestry and young onset (YOPD) Ashkenazi Jewish and Afro-Caribbean patients. There is little information on the prevalence of DJ-1 mutations amongst Asian PD populations. In this study, we examined for DJ-1 mutations in consecutive YOPD and ARPD in a multi-ethnic cohort (Chinese, Malays, and Indians) of PD patients in a tertiary referral center. Sequence analysis of all the exons and the exon and intron boundaries of the DJ-1 gene were carried out. We did not find any DJ-1 mutations in these patients. A number of intronic variants with genotype frequency ranging from 15 to 90% were detected. Unlike Parkin, pathogenic DJ-1 mutations appear to be restricted to certain populations and are unlikely to be of clinical importance in our Asian cohort.     

The G2019S LRRK2 mutation is uncommon in an Asian cohort of Parkinson's disease patients

A common heterozygous leucine-rich repeat kinase 2 (LRRK2) mutation 6055G > A transition (G2019S) accounts for about 3-7% of familial Parkinson's disease (PD) and 1-1.6% sporadic PD in a number of European populations. To determine the prevalence of the G1019S mutation in our Asian population, we conducted genetic analysis of this mutation in 1000 PD and healthy controls. The G2019S mutation was not detected in any of our study subjects. The prevalence of G2019S mutation is rare (< 0.1%) in our population, suggesting that occurrence of this mutation may vary amongst different ethnic races. This has important clinical implication when implementing guidelines for genetic testing.     

Case-control study of UCHL1 S18Y variant in Parkinson's disease.

A recent meta-analysis observed a greater significant inverse association of the ubiquitin carboxy-terminal hydrolase L1 (UCHL1) S18Y variant with Parkinson's disease (PD) for Asian (predominantly Japanese) populations compared with Caucasian populations. We performed an independent case-control study in 335 PD and 341 control subjects with data from a Chinese population to investigate the age-of-onset effect of the UCHL1 variant in PD. The Y/Y and Y/S genotypes were less frequent in the PD young-onset group than in controls and the frequency of the Y alleles was higher in young controls compared to young-onset PD (age at examination 相似文献