Biomedical subjects

Cristina Sampaio

Publications and source records attributed to Cristina Sampaio.

At least 19 recordsLinked to original sources

PubMed2026

From genes to trajectories: mapping genetic influences on Huntington's disease progression.

MOTIVATION: There are many diseases with established genetic factors, such as Huntington's disease (HD), that are characterized by variable rates of progression. However, beyond the contribution of the known genetic factors - in this case the Huntingtin (HTT) gene - the impact of the full human genome on the natural progression of such diseases throughout a patient's life remains largely unknown. The increased availability of genome wide association (GWA) data in HD gene expansion carriers (HDGECs), combined with the clinical assessment scores on the same set of patients, has provided a perfect opportunity to assess the potentially broader genetic impact on the natural progression of HD. RESULTS: We present a genetics-driven, probabilistic disease progression model designed to identify and investigate the ways in which a range of genetic factors affect the natural progression of HD. When applied to a clinico-genomic HD dataset, our model identified several single nucleotide polymorphisms (SNPs) with previously unreported effects on disease progression that act at distinct stages and with varying magnitudes. This discovery may shed light on the potential mechanistic impact of previously unidentified genes on HD that may have implications for clinical management. As increasing amounts of GWA data become available more generally, we anticipate that this modeling framework will be broadly applicable to other diseases with strong genetic components. AVAILABILITY AND IMPLEMENTATION: The source code for IHDPM is available at https://github.com/BiomedSciAI/IHDPM.

Huntington Disease↗

PubMed2007

Movement Disorder Society-sponsored revision of the Unified Parkinson's Disease Rating Scale (MDS-UPDRS): Process, format, and clinimetric testing plan.

This article presents the revision process, major innovations, and clinimetric testing program for the Movement Disorder Society (MDS)-sponsored revision of the Unified Parkinson's Disease Rating Scale (UPDRS), known as the MDS-UPDRS. The UPDRS is the most widely used scale for the clinical study of Parkinson's disease (PD). The MDS previously organized a critique of the UPDRS, which cited many strengths, but recommended revision of the scale to accommodate new advances and to resolve problematic areas. An MDS-UPDRS committee prepared the revision using the recommendations of the published critique of the scale. Subcommittees developed new material that was reviewed by the entire committee. A 1-day face-to-face committee meeting was organized to resolve areas of debate and to arrive at a working draft ready for clinimetric testing. The MDS-UPDRS retains the UPDRS structure of four parts with a total summed score, but the parts have been modified to provide a section that integrates nonmotor elements of PD: I, Nonmotor Experiences of Daily Living; II, Motor Experiences of Daily Living; III, Motor Examination; and IV, Motor Complications. All items have five response options with uniform anchors of 0 = normal, 1 = slight, 2 = mild, 3 = moderate, and 4 = severe. Several questions in Part I and all of Part II are written as a patient/caregiver questionnaire, so that the total rater time should remain approximately 30 minutes. Detailed instructions for testing and data acquisition accompany the MDS-UPDRS in order to increase uniform usage. Multiple language editions are planned. A three-part clinimetric program will provide testing of reliability, validity, and responsiveness to interventions. Although the MDS-UPDRS will not be published until it has successfully passed clinimetric testing, explanation of the process, key changes, and clinimetric programs allow clinicians and researchers to understand and participate in the revision process.

Disability Evaluation↗

PubMed2007

Disease-modifying trials in Alzheimer's disease: a European task force consensus.

After symptomatic treatments, the new target for therapeutic approaches in Alzheimer's disease is the development of disease-modifying drugs. The concept of disease modification in Alzheimer's disease is controversial and the design of these trials raises many questions. Which populations should be studied? For how long? With which principal and secondary endpoints? Are surrogate markers available? Here, we present a European consensus on disease-modifying trials in Alzheimer's disease, agreed under the auspices of the European Alzheimer's Disease Consortium and based on the European perspective of the concept of disease modification, study designs, the role for biomarkers, risk benefit, and pharmacoeconomic issues.

Aged↗

PubMed2006

Pergolide versus levodopa monotherapy in early Parkinson's disease patients: The PELMOPET study.

Dopamine agonists are used as initial treatment in patients with Parkinson's disease (PD) to reduce incidence and severity of motor complications. This paradigm is based on long-term studies, allowing "rescue" therapy with levodopa. The present strict monotherapy study (PELMOPET, the acronym for the pergolide-versus-L-dopa-monotherapy-and-positron-emission-tomography trial) evaluated the efficacy and safety of pergolide versus levodopa without levodopa "rescue" medication. This multicenter, double-blind, randomized, 3-year trial compared pergolide monotherapy (n=148) with levodopa monotherapy (n=146) in dopamine-naive patients with early PD (Hoehn and Yahr stage 1-2.5). Primary efficacy measures were clinical efficacy, severity and time to onset of motor complications, and disease progression. During the 3 years, severity of motor complications was significantly lower and time to onset of dyskinesia was significantly delayed in the group receiving pergolide (3.23 mg/day) compared with those receiving levodopa (504 mg/day). However, time to onset of motor complications was not longer in patients receiving pergolide after 3 years. Symptomatic relief (assessed by Unified Parkinson's Disease Rating Scale [UPDRS], UPDRS II, and III, Clinical Global Impressions [CGI] severity, and CGI and Patient Global Impressions [PGI] improvement) was significantly greater in patients receiving levodopa. Adverse events led to discontinuation of therapy in 17.6% of pergolide patients and 9.6% of levodopa patients. This is the first study comparing strict monotherapy with a dopamine agonist versus levodopa in previously untreated early PD. In principle, both levodopa and a dopamine agonist such as pergolide seem to be suitable options as initial PD therapy. The choice remains with the treating physician based on the different efficacy and adverse event profiles.

Adult↗

PubMed2006

Health-related quality of life in multiple system atrophy.

Although multiple system atrophy (MSA) is a neurodegenerative disorder leading to progressive disability and decreased life expectancy, little is known about patients' own evaluation of their illness and factors associated with poor health-related quality of life (Hr-QoL). We, therefore, assessed Hr-QoL and its determinants in MSA. The following scales were applied to 115 patients in the European MSA-Study Group (EMSA-SG) Natural History Study: Medical Outcome Study Short Form (SF-36), EQ-5D, Beck Depression Inventory (BDI), Mini-Mental state examination (MMSE), Unified MSA Rating Scale (UMSARS), Hoehn & Yahr (H&Y) Parkinson's disease staging scale, Composite Autonomic Symptom Scale (COMPASS), and Parkinson's Disease Sleep Scale (PDSS). Forty-six percent of patients had moderate to severe depression (BDI > or = 17); Hr-QoL scores on the SF-36 and EQ-5D were significantly impaired. Pain, the only domain with similar scores in MSA and published PD patients, was reported more frequently in patients with MSA-P (predominantly parkinsonian motor subtype) than MSA-C (predominantly cerebellar motor subtype; 76% vs. 50%; P = 0.005). Hr-QoL scores correlated most strongly with UMSARS motor, COMPASS, and BDI scores but not with MMSE scores, age at onset, or disease duration. The COMPASS and UMSARS activities of daily living scores were moderate-to-strong predictors for the SF-36 physical summary score and the BDI and UMSARS motor scores for the SF-36 mental summary score. This report is the first study to show that Hr-QoL is significantly impaired in MSA. Although not all possible factors related to impaired Hr-QoL in MSA could be assessed, autonomic dysfunction, motor impairment, and depression were most closely associated with poor Hr-QoL, and therapeutic management, therefore, should concentrate upon these aspects of the disease.

Anxiety↗

PubMed2006

Minimal clinically important change on the unified Parkinson's disease rating scale.

The Unified Parkinson's Disease Rating Scale (UPDRS) is the main outcome measure in clinical trials of Parkinson's disease (PD). The minimal change that represents a clinically meaningful improvement is unknown. The objective of this study was to determine the minimal change on the UPDRS that represents a clinically meaningful improvement in early PD after 6 months of treatment. Data from two independent randomized treatment trials over 6 months involving 603 patients with de novo PD were analyzed to determine the minimal clinically important change (MCIC), referred to the status before treatment, for the UPDRS motor, activities of daily living (ADL), and total scores. An anchor-based method using ratings on a seven-point global clinical improvement was used. A change of five points on the UPDRS motor part was found to be the most appropriate cutoff score for all Hoehn and Yahr stages I to III, and a change of eight points for the UDPRS total score. For the UDPRS ADL score, an MCIC of two points for Hoehn and Yahr stages I/I.5 and II and of three points for Hoehn and Yahr stage II.5/III was the most appropriate cutoff score. These data give the first estimate for cutoffs defining clinically important changes in UPDRS ADL and motor scores. Further studies using larger databases from more diverse study populations are encouraged to better define and solidify the MCIC for the UPDRS.

Aged↗

PubMed2006

Comprehensive analysis of the LRRK2 gene in sixty families with Parkinson's disease.

Mutations in the gene leucine-rich repeat kinase 2 (LRRK2) have been recently identified in families with Parkinson's disease (PD). However, the prevalence and nature of LRRK2 mutations, the polymorphism content of the gene, and the associated phenotypes remain poorly understood. We performed a comprehensive study of this gene in a large sample of families with Parkinson's disease compatible with autosomal dominant inheritance (ADPD). The full-length open reading frame and splice sites of the LRRK2 gene (51 exons) were studied by genomic sequencing in 60 probands with ADPD (83% Italian). Pathogenic mutations were identified in six probands (10%): the heterozygous p.G2019S mutation in four (6.6%), and the heterozygous p.R1441C mutation in two (3.4%) probands. A further proband carried the heterozygous p.I1371 V mutation, for which a pathogenic role could not be established with certainty. In total, 13 novel disease-unrelated variants and three intronic changes of uncertain significance were also characterized. The phenotype associated with LRRK2 pathogenic mutations is the one of typical PD, but with a broad range of onset ages (mean 55.2, range 38-68 years) and, in some cases, slow disease progression. On the basis of the comprehensive study in a large sample, we conclude that pathogenic LRRK2 mutations are frequent in ADPD, and they cluster in the C-terminal half of the encoded protein. These data have implications both for understanding the molecular mechanisms of PD, and for directing the genetic screening in clinical practice.

Adult↗

PubMed2006

Processes leading to confidence and accuracy in sentence recognition: a metamemory approach.

We propose that memory confidence is based on the processes and products of the just-completed memory task, along with the participants' metamemory beliefs about the relation of these processes and products to memory accuracy. We tested this metamemory approach to confidence by having participants carry out a simple recognition memory task with deceptive and nondeceptive items. The deceptive items were sentences that contained a possible synonym substitution, thus allowing errors based on gist memory. For nondeceptive items, high confidence was associated with high accuracy. For deceptive items the relationship reversed; high confidence was associated with low accuracy. A memory process questionnaire was developed that provided more differentiated phenomenal reports than the traditional know/remember distinction. For nondeceptive items, metamemory beliefs tended to be valid indicators of accuracy, but for deceptive items involving unconscious reconstructive memory processes, they tended to be invalid indicators of memory accuracy. The overall results lend strong support for our metamemory approach to memory confidence.

Cues↗

PubMed2005

Evidence-based medical review update: pharmacological and surgical treatments of Parkinson's disease: 2001 to 2004.

The objective of this study is to update a previous evidence-based medicine (EBM) review on Parkinson's disease (PD) treatments, adding January 2001 to January 2004 information. The Movement Disorder Society (MDS) Task Force prepared an EBM review of PD treatments covering data up to January 2001. The authors reviewed Level I (randomized clinical trials) reports of pharmacological and surgical interventions for PD, published as full articles in English (January 2001-January 2004). Inclusion criteria and ranking followed the original program and adhered to EBM methodology. For Efficacy Conclusions, treatments were designated Efficacious, Likely Efficacious, Non-Efficacious, or Insufficient Data. Four clinical indications were considered for each intervention: prevention of disease progression; treatment of Parkinsonism, as monotherapy and as adjuncts to levodopa where indicated; prevention of motor complications; treatment of motor complications. Twenty-seven new studies qualified for efficacy review, and others covered new safety issues. Apomorphine, piribedil, unilateral pallidotomy, and subthalamic nucleus stimulation moved upward in efficacy ratings. Rasagiline, was newly rated as Efficacious monotherapy for control of Parkinsonism. New Level I data moved human fetal nigral transplants, as performed to date, from Insufficient Data to Non- efficacious for the treatment of Parkinsonism, motor fluctuations, and dyskinesias. Selegiline was reassigned as Non-efficacious for the prevention of dyskinesias. Other designations did not change. In a field as active in clinical trials as PD, frequent updating of therapy-based reviews is essential. We consider a 3-year period a reasonable time frame for published updates and are working to establish a Web-based mechanism to update the report in an ongoing manner.

Amantadine↗

PubMed2005

Prevalence and incidence of Parkinson's disease in Europe.

OBJECTIVE: To provide an overview on the prevalence and incidence of Parkinson's disease (PD) in selected European countries. BACKGROUND: PD is a common disease of unknown etiology. Accurate information on the epidemiology of PD is critical to inform health policy. An aging population will lead to more patients with PD; thus, the high financial burden PD places on society will increase. MATERIAL AND METHODS: A systematic literature search was performed to identify studies on the prevalence and incidence of PD in the following European countries: Austria, the Czech Republic, France, Germany, Italy, The Netherlands, Portugal, Spain, Sweden and United Kingdom. Only published studies were included. Abstracts, reviews, meta-analyses and letters to the editor were excluded. There were no language restrictions. Data were extracted using a standardized assessment form, and evidence tables were used to systematically report and compare the data. RESULTS: Of 39 identified studies, most (87%) reported estimates of PD prevalence rates, while only a few (13%) reported estimates of PD annual incidence rates. Crude prevalence rate estimates ranged from 65.6 per 100,000 to 12,500 per 100,000 and annual incidence estimates ranged from 5 per 100,000 to 346 per 100,000. No publications could be identified for Austria or the Czech Republic. DISCUSSION AND CONCLUSION: The observed variations in prevalence and incidence rates may result from environmental or genetic factors, but might also be a consequence of differences in methodologies for case ascertainment, diagnostic criteria, or age distributions of the study populations. The comparability of existing studies is limited.

Age Distribution↗

PubMed2005

Essential tremor.

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Adrenergic beta-Antagonists↗

PubMed2004

Clinical comparability of marketed formulations of botulinum toxin.

The majority of pharmaceutical products are patented in early phases of their discovery to preclude competition by similar products. Due to unusual circumstances (botulinum toxin is an unpatentable natural product and it is considered to be a biological weapon), technology know-how for botulinum toxin production was classified rather then available in the scientific community. Botulinum toxin type A was marketed in two pharmaceutical distinct formulations from competitor companies. Serendipity proved that the two formulations were not equipotent in terms of mouse units. From a regulatory point of view, differences in potency of distinct formulations are not a matter of concern because each formulation is licensed based on its own set of data. As far as the data in each case is sufficient to prove that a particular formulation is safe and efficacious at its defined dosage, a license for use can be granted. On the other hand, generation of data on comparability is the only way that clinicians and managers can ascertain which product (formulation, serotype) is most cost-effectiveness and to determine whether there are relevant differences in their safety profiles. The results of the systematic review of head-to-head randomised trials comparing BOTOX to Dysport suggest that the two formulations are not bioequivalent whatever the dose relationship. Data on comparative immunogenicity are not available. The indirect comparison of the results obtained in randomised clinical trials comparing BOTOX to placebo and Dysport to placebo support that intrinsic differences are present in the two products. It is concluded that comparative economic evaluations of different botulinum toxin formulations should move away from cost-minimization approaches based on the presumption of bioequivalence and move toward cost-effectiveness or cost-utility models.

Aged↗

PubMed2004

Movement Disorder Society Task Force report on the Hoehn and Yahr staging scale: status and recommendations.

The Movement Disorder Society Task Force for Rating Scales for Parkinson's disease (PD) prepared a critique of the Hoehn and Yahr scale (HY). Strengths of the HY scale include its wide utilization and acceptance. Progressively higher stages correlate with neuroimaging studies of dopaminergic loss, and high correlations exist between the HY scale and some standardized scales of motor impairment, disability, and quality of life. Weaknesses include the scale's mixing of impairment and disability and its non-linearity. Because the HY scale is weighted heavily toward postural instability as the primary index of disease severity, it does not capture completely impairments or disability from other motor features of PD and gives no information on nonmotor problems. Direct clinimetric testing of the HY scale has been very limited, but the scale fulfills at least some criteria for reliability and validity, especially for the midranges of the scale (Stages 2-4). Although a "modified HY scale" that includes 0.5 increments has been adopted widely, no clinimetric data are available on this adaptation. The Task Force recommends that: (1) the HY scale be used in its original form for demographic presentation of patient groups; (2) when the HY scale is used for group description, medians and ranges should be reported and analysis of changes should use nonparametric methods; (3) in research settings, the HY scale is useful primarily for defining inclusion/exclusion criteria; (4) to retain simplicity, clinicians should "rate what you see" and therefore incorporate comorbidities when assigning a HY stage; and (5) because of the wide usage of the modified HY scale with 0.5 increments, this adaptation warrants clinimetric testing. Without such testing, however, the original five-point scales should be maintained.

Feasibility Studies↗

PubMed2004

Development and validation of the Unified Multiple System Atrophy Rating Scale (UMSARS).

We aimed to develop and validate a novel rating scale for multiple system atrophy (Unified Multiple System Atrophy Rating Scale-UMSARS). The scale comprises the following components: Part I, historical, 12 items; Part II, motor examination, 14 items; Part III, autonomic examination; and Part IV, global disability scale. For validation purposes, 40 MSA patients were assessed in four centers by 4 raters per center (2 senior and 2 junior raters). The raters applied the UMSARS, as well as a range of other scales, including the Unified Parkinson's Disease Rating Scale (UPDRS) and the International Cooperative Ataxia Rating Scale (ICARS). Internal consistency was high for both UMSARS-I (Crohnbach's alpha = 0.84) and UMSARS-II (Crohnbach's alpha = 0.90) sections. The interrater reliability of most of the UMSARS-I and -II items as well as of total UMSARS-I and -II subscores was substantial (k(w) = 0.6-0.8) to excellent (k(w) > 0.8). UMSARS-II correlated well with UPDRS-III and ICARS (rs > 0.8). Depending on the degree of the patient's disability, completion of the entire UMSARS took 30 to 45 minutes. Based on our findings, the UMSARS appears to be a multidimensional, reliable, and valid scale for semiquantitative clinical assessments of MSA patients.

Activities of Daily Living↗

PubMed2004

Assessment of time perception: the effect of aging.

Studies concerning time perception lack a validated assessment tool and a consensual "gold-standard" measure. Moreover, the present evidence suggests modification of timing with aging. This study aimed to develop and validate a neuropsychological tool to measure time perception and to study temporal perception with aging. Eighty-six healthy participants, aged 15-90 years old, were asked to verbally estimate and produce empty intervals signaled by auditory beeps, of 7-, 32-, and 58-s duration. Two tests were used as "gold-standards": estimation of the duration of time necessary to draw a clock ("clock time") and estimation of the duration of neuropsychological evaluation ("global time"). Results showed a correlation between estimation and production (p < .01) and a correlation between estimation or production and "global time" (p < .01). The correlation between either estimation or production and age (p < .01), suggested a faster "internal-clock" in the older participants. However, this finding lost significance when controlled for literacy. The results suggest that these tests are potentially a useful tool to measure subjective perception of time. They also corroborate the hypothesis of a change in subjective time perception with aging. It was not possible to conclude if this effect was a specific result of aging or biased by the interference of literacy.

Adolescent↗

PubMed2004

Essential tremor.

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Barbiturates↗

PubMed2003

Essential tremor.

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Adrenergic beta-Antagonists↗

PubMed2002

Treatment interventions for Parkinson's disease: an evidence based assessment.

We did a systematic review, with a uniform method of assessment of efficacy and safety, to assess the different interventions available for the management of Parkinson's disease (drugs, surgical interventions, and physical treatments) with respect to the following indications: prevention of disease progression, symptomatic treatment of motor features (parkinsonism), symptomatic control of motor complications, prevention of motor complications, and symptomatic treatment of non-motor features. Our aim was not to define practice guidelines, but rather to improve clinicians' knowledge of the presently available published clinical evidence, based mainly on randomised controlled trials. We hope that our review will help doctors to incorporate this background into their own decision-making strategy to make appropriate choices with respect to the treatment of individual patients with Parkinson's disease.

Disease Progression↗