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PubMed2006

Attention-deficit/hyperactivity disorder: use of cognitive evoked potential (P300) to predict treatment response.

OBJECTIVE: To evaluate the use of P300 in predicting treatment response to medicines in patients with Attention-Deficit/Hyperactivity Disorder (ADHD), and to confirm previous reports that 31-electrode mean auditory P300 amplitude (AA) predicts response to atomoxetine; and right fronto-central to parietal AA ratio predicts response to methylphenidate. METHODS: Efficacy and P300 data from 58 children with ADHD enrolled in a double-blind crossover study using atomoxetine and methylphenidate were analyzed. Robust response was defined as 60% decrease from baseline in the ADHD rating scale. Response was alternately defined as greater than 50% decrease. RESULTS: Pre-treatment mean 31-electrode AA>6.8 microV predicted response to atomoxetine using both definitions of response. Right fronto-central to parietal AA ratio did not predict response to methylphenidate. A previous report that methylphenidate responders differed from non-responders in pre-treatment AA at T8 was confirmed, and AA at T8>7.65 microV predicted response to methylphenidate. 31-electrode mean P300 visual latency (VL) also predicted response to atomoxetine, as previously reported with imipramine. CONCLUSIONS: Mean AA predicts response to atomoxetine in ADHD patients. AA at T8 predicts response to methylphenidate. Such predictive tools may allow individually tailored choice of medicine in treatment of ADHD. SIGNIFICANCE: This allows a more informed decision of which medicine to use for a given patient.

Acoustic Stimulation↗
PubMed2005

Can initial and additional compensatory steps be predicted in young, older, and balance-impaired older females in response to anterior and posterior waist pulls while standing?

The initiation of a single compensatory step in response to balance perturbations has been predicted with accuracies of up to 71%. We sought to determine whether similar methods also could be used to predict the onset of additional compensatory steps in both healthy and balance-impaired older females. Anterior and posterior waist pulls of five different magnitudes were applied to 13 unimpaired young (mean age 23 years), 12 unimpaired older (mean age 71 years), and 15 balance-impaired older (mean age 76 years) women. Body segment kinematic data were recorded at 100 Hz. A step was predicted when the time for the center-of-mass to reach the vertical projection of the boundary of the base-of-support fell below a certain threshold. The results show that 83% of all steps and non-steps were correctly predicted at an optimal time-to-boundary threshold (tau(opt)) of 0.78 s. Step prediction accuracy did not differ significantly by group: 86% of steps and non-steps by young, 84% by unimpaired old, and 82% by balance-impaired old women were correctly predicted at tau(opt) of 0.58, 0.67, and 0.78 s, respectively. Anterior steps and non-steps were predicted more accurately than posterior ones (94% vs. 79% correct at tau(opt) of 0.52 and 0.84 s, respectively) and initial steps were better predicted than additional ones (87% vs. 81% correct at tau(opt) of 0.77 and 0.34 s, respectively). We conclude that this step prediction method reasonably predicts initial and additional steps in the anterior and posterior direction by all three subject cohorts.

Accidental Falls↗
PubMed2004

Common comorbidity scales were similar in their ability to predict health care costs and mortality.

OBJECTIVE: To compare the ability of commonly used measures of medical comorbidity (ambulatory care groups [ACGs], Charlson comorbidity index, chronic disease score, number of prescribed medications, and number of chronic diseases) to predict mortality and health care costs over 1 year. STUDY DESIGN AND SETTING: A prospective cohort study of community-dwelling older adults (n=3,496) attending a large primary care practice. RESULTS: For predicting health care charges, the number of medications had the highest predictive validity (R(2)=13.6%) after adjusting for demographics. ACGs (R(2)=16.4%) and the number of medications (15.0%) had the highest predictive validity for predicting ambulatory visits. ACGs and the Charlson comorbidity index (area under the receiver operator characteristic [ROC] curve=0.695-0.767) performed better than medication-based measures (area under the ROC curve=0.662-0.679) for predicting mortality. There is relatively little difference, however, in the predictive validity across these scales. CONCLUSION: In an outpatient setting, a simple count of medications may be the most efficient comorbidity measure for predicting utilization and health-care charges over the ensuing year. In contrast, diagnosis-based measures have greater predictive validity for 1-year mortality. Current comorbidity measures, however, have only poor to moderate predictive validity for costs or mortality over 1 year.

Black or African American↗
PubMed2000

From fold recognition to homology modeling: an analysis of protein modeling challenges at different levels of prediction complexity.

An analysis of different approaches to protein structure prediction is presented based solely on the range of models submitted to the third Critical Assessment of Protein Structure Prediction (CASP3) conference. CASP conferences evaluate the current state of the art of protein structure prediction by comparing blind prediction efforts of many groups for the same set of target sequences. Target sequences may be highly similar to those with known structure or can be totally (at least superficially) sequentially dissimilar. Techniques applied to those blind predictions (over 40 targets) ranges from a detailed homology prediction to the detection of remote homologues well below a twilight zone of protein sequence similarity. For the CASP3 conference, we have submitted predictions, totaling 35, with various levels of difficulty and complexity. For ten submitted homology targets, eight of them were determined by experiment so far. The RMSD of C-alpha atoms are 1.2-1.7, 2.3, and 4.6-17.9 A for the three easy targets, two hard targets, and three very hard homology targets, respectively. Out of 18-fold recognition predictions available for analysis, we got six correct predictions, five near misses, three tough near misses and four far misses. Here we analyze successes and failures of those predictions in an attempt to identify common problems and common achievements.

Computer Simulation↗
PubMed1998

Prediction of sensitization to inhalant allergens in childhood: evaluating family history, atopic dermatitis and sensitization to food allergens. The MAS Study Group. Multicentre Allergy Study.

BACKGROUND: A family history of atopy is a poor predictor of sensitization to inhalant allergens and allergic disease during childhood. We recently identified early sensitization to food allergens, especially hen's egg, as a valuable predictor of subsequent sensitization to inhalant allergens. OBJECTIVE: (1) Whether prediction will be improved by in vitro allergy tests at 1 year of age in combination with family history and medical history data. (2) Comparison with the capacities of in vitro tests to predict sensitization to aeroallergens. METHODS: Of an observational birth cohort study (MAS) 49 children who were sensitized to inhalant allergens at 5 years of age and 116 non-sensitized controls were included in the present study. For the prediction of sensitization to inhalant allergens the following prognostic factors were evaluated: atopic family history (FH), atopic dermatitis (AD) during the first year of life, two in vitro allergy tests for specific IgE to common food allergens at 1 year of age (fx5 [Pharmacia] and single allergen specific tests (sIgE) for four allergens) and 'high' total serum IgE, defined by three different cut off points. RESULTS: The combination of medical history data and laboratory tests resulted in the best predictive discrimination. The positive predictive values (PPV) were higher if sensitization to food was detected by single allergen specific tests (PPV: 66%/75%/100% corresponding to the three evaluated risk groups) than by the qualitative fx5 (PPV: 46%/65%/100%). The negative predictive values were equal for both tests (69 and 92% for the two low risk groups). High total serum IgE had low predictive capacity. CONCLUSION: During infancy the prediction of sensitization to inhalant allergens should be based on medical history data and allergy tests determining sensitization to food allergens. The in vitro tests improve the predictive discrimination, but the individual risk profile of the child must be considered for a reliable and valid prediction.

Allergens↗
PubMed2001

Prediction of five-year survival for patients admitted to a department of internal medicine.

OBJECTIVE: The effect of many common forms of therapy, as medication for mild hypertension or hypercholesterolaemia, only reaches clinical significance after years of treatment. The meaningful application of such therapy presupposes that physicians can, at least to some extent, predict the remaining lifetime of patients. We investigated whether clinicians from different disciplines were able to predict the 5-year survival of patients admitted to a department of internal medicine. DESIGN: The members of two groups, each consisting of an internist, a surgeon and a general practitioner, made individual predictions of the expected remaining lifetime of discharged patients from written summaries of clinical information. Each patient was randomized to be assessed by the members of either of the two groups. The predictions were compared with actual 5-year survival. SETTING: Department of internal medicine at a university hospital. SUBJECTS: Patients admitted consecutively during a 6-week period. MAIN OUTCOME MEASURES: Sensitivity, specificity, positive and negative predictive values and areas under the receiver operating characteristic (ROC) curves for predictions of 5-year survival for each of the six experts. RESULTS: A total of 402 patients were included. Five-year survival was 0.63. The sensitivity of the predictions ranged from 0.81 to 0.95, the specificity from 0.61 to 0.77, the positive predictive value from 0.78 to 0.87 and the negative predictive value from 0.68 to 0.87. The areas under the ROC curves ranged from 0.84 to 0.91. CONCLUSION: The quality of predictions of 5-year survival made by experienced clinicians should permit the rational use of treatments with long-term effects.

Adult↗
PubMed2006

[CT-based software-supported prediction of the postoperative lung function after partial resection of the lung].

PURPOSE: The predicted postoperative forced exspiratory volume in one second (FEV (1)) is an important functional factor for predicting the operability of patients with bronchial carcinoma. A software tool that uses a preoperative chest MSCT and pulmonary function test (PFT) for largely automated prediction of the FEV (1) was evaluated. MATERIALS AND METHODS: Fifteen patients with surgically treated lung cancer were examined with a preoperative chest MSCT (1.25 mm slice thickness, 0.8 mm reconstruction increment) and PFT before and after surgery. CT scans were analyzed by the prototype software MeVisPulmo (MeVis gGmbH, Bremen) that predicted the postoperative FEV (1) as a percentage of the preoperative values measured by PFT. The automated segmentation and volumetry of lung lobes were performed either without or with minimal user interaction. Patients underwent lobectomy in twelve cases (6 upper lobes, 1 middle lobe, 5 lower lobes) and pneumectomy in three cases. The predicted FEV (1) values were compared to the observed postoperative values as a standard of reference. The additional functional parameters "total lung capacity" (TLC) and "forced vital capacity" (FVC) were compared to the FEV (1) results. RESULTS: Automated calculation of predicted postoperative lung function was successful in all cases. Due to an implausible PFT, two of the 15 patients were excluded from the collective. A mean postoperative FEV (1) value of 75 % (SD +/- 12 %) of the preoperative FEV (1) was calculated and 74 % (SD +/- 12 %) was actually measured. The deviations of the predicted value from the measured postoperative FEV (1) ranged between - 289 ml (-12 % of the measured postoperative FEV (1)) and + 294 ml (+ 15 % of the postoperative FEV (1)). The mean deviation (absolute value) was 137 +/- 77 ml/s. This corresponds to 7 +/- 3 % of the measured postoperative FEV (1). Bland-Altman-Statistics showed the 95 % "limits of agreement" for the predicted FEV (1) values to be between - 341 ml and + 301 ml, corresponding to - 17.5 % and + 15.8 of the measured postoperative FEV (1) value. Analysis of the TLC and FVC yielded similar results. CONCLUSION: In the present pilot study the software-assisted prediction of the postoperative FEV (1) using a preoperative MSCT and pulmonary function test corresponded satisfactorily with the observed postoperative values. The introduced approach may make it possible to obtain additional information for the prediction of functional operability prior to performing lung cancer surgery.

Adenocarcinoma↗
PubMed2003

Reducing unnecessary cross-matching: a patient-specific blood ordering system is more accurate in predicting who will receive a blood transfusion than the maximum blood ordering system.

UNLABELLED: Most blood transfusions are given in the operating room. Adoption of the Maximum Surgical Blood Ordering Schedule in the 1970s reduced the amount of blood unnecessarily cross-matched, but the national cross-match-to-transfusion ratio remains at approximately two-to-one. We tested the ability of a patient-specific blood ordering system (PSBOS) to more accurately predict potential operative transfusion. All adult patients who had blood cross-matched before surgery (February through June 1999) for elective operative procedures at the University of Michigan Hospital were identified. Complex surgeries were excluded. Surgeons estimated the expected blood loss for their surgeries, and the expected postoperative hematocrit was calculated using the patient's blood volume, the surgeon-defined expected blood loss, and preoperative hematocrit. Lowest tolerated hematocrit was set at 21% except in patients with coronary artery disease or who were ASA physical status III or more (28%). Sensitivity, specificity, positive predictive value, and negative predictive value of the PSBOS were calculated. Our analysis included 178 cases in which blood was cross-matched before surgery, representing 69 different surgeries and 42 surgeons. Only 16% of patients received an intraoperative transfusion. Of the 156 patients that PSBOS predicted would not require an operating room transfusion, 139 were not transfused. Of the 21 patients PSBOS predicted would be transfused, 11 were. The sensitivity of the algorithm as tested was 41%, the specificity 93%, the positive predictive value was 55%, and the negative predictive value was 89%. We conclude that PSBOS, which includes patient and surgeon variables in transfusion prediction, is more accurate than the Maximum Surgical Blood Ordering Schedule, which uses only surgical procedure. IMPLICATIONS: Currently, many units of blood set aside for surgery are never required, resulting in extra work and expense for blood banks. A formula that included patient weight and hematocrit and typical surgery blood loss was used to predict who would require transfusions. We reduced the predicted number of patients who had blood set aside from 178 to 21.

Adolescent↗
PubMed1998

Understanding articles describing clinical prediction tools. Evidence Based Medicine in Critical Care Group.

OBJECTIVES: Clinical prediction rules and models are developed by applying statistical techniques to find combinations of predictors that categorize a heterogeneous group of patients into subgroups of risk. Our goal is to teach clinicians how to evaluate the validity, results, and applicability of articles describing clinical prediction tools. CLINICAL EXAMPLE: An article describing a rule to predict the need for intensive care unit care admission in patients presenting to the emergency room with chest pain. RECOMMENDATIONS: Valid clinical prediction tools are developed by completely following up a representative group of patients, by evaluating all potential predictors and testing the independent contribution of each predictor variable, and by ensuring that the outcomes were independent of the predictors. To evaluate the results of an article describing a clinical prediction tool, clinicians need to know what the prediction tool is, how well it categorizes patients into different levels of risk, and what the confidence intervals are around the risk estimates. Valid prediction tools are not applicable in every patient population. Before patient care application, the clinician should ensure that the tool maintains its prediction power in a new sample of patients, that the patients are similar to patients used to test the tool, and that the tool has been shown to improve clinical decision-making. CONCLUSIONS: There has been an increase in the development and validation of clinical prediction rules and models. It is important to evaluate the validity and reliability of these prediction tools before application.

APACHE↗
PubMed2002

Use of plasma lactate to predict early mortality and adverse outcome after neonatal extracorporeal membrane oxygenation: a prospective cohort in early childhood.

OBJECTIVE: To examine the use of plasma lactate levels to predict mortality and neurodevelopmental outcome of neonates treated with extracorporeal membrane oxygenation. DESIGN: Prospective cohort study. SETTING: Two level III neonatal intensive care units in Canada and the United States. PATIENTS: Seventy-four neonates requiring extracorporeal membrane oxygenation in two neonatal intensive care units from 1994 to 1996. INTERVENTIONS: Differences in clinical and biochemical measurements, including serial lactate levels between three outcome groups (early deaths, adverse survivors, and normal survivors) were compared using analysis of variance. We also examined the predictive relationship between plasma lactate levels and the outcome at neonatal intensive care unit discharge and at 18-24 months postnatal age by backward, stepwise regression and Fisher's exact test. MEASUREMENTS AND MAIN RESULTS: Fifteen (20%) neonates died before neonatal intensive care unit discharge (early deaths), with seven additional deaths before follow-up, which are included in the adverse survivors group. Among 49 early childhood survivors (22 +/- 7 months), 27 were disabled or delayed with Mental and Performance Developmental Indices of 70 +/- 21 and 72 +/- 22, respectively. Early deaths had higher plasma lactate levels and were more acidemic than adverse and normal survivors, who were not different from each other (p <.05). Plasma lactate and the lowest arterial pH independently predicted 42% of the variance of the outcome ( p<.001). A peak lactate level of >or=25 mM predicted early mortality (sensitivity, 47%; specificity, 100%; positive and negative predictive values, 100% and 88%, respectively; p<.001), whereas a level of >or=15 mM predicted adverse outcome (sensitivity, 35%; specificity, 91%; positive and negative predictive values, 89% and 38%, respectively; p<.05). The predictability of plasma lactate was significantly improved in 45 neonates without congenital diaphragmatic hernia or lethal anomalies (sensitivity of 100% for early mortality, negative predictive value of 63% for adverse outcome). CONCLUSIONS In addition to assessing tissue oxygenation, plasma lactate may facilitate the decision-making process by providing early predictive information about the outcome of neonates treated with extracorporeal membrane oxygenation.

Analysis of Variance↗
PubMed1998

Accuracy of predicted ear canal speech levels using the VIOLA input/output-based fitting strategy.

OBJECTIVE: The Visual Input/Output Locator Algorithm (VIOLA) is a software-assisted method for prescribing amplification targets and selecting a hearing aid to match the targets. Although the procedure calls for selection and fitting of hearing aids in terms of their pure-tone input/output functions in a coupler, it is assumed that a hearing aid that matches the coupler prescription targets will produce specific amplified speech levels in the patient's ear canal. This investigation evaluated the validity of that assumption. DESIGN: Six hearing aids were evaluated. They were representative of linear and compression processing as well as single- and 2-channel designs. The "subject" was a KEMAR manikin with realistic assumed hearing loss and loudness perception characteristics. Each hearing aid was configured to match the subject's VIOLA prescription as closely as possible. Predicted ear canal speech levels were determined using the prescription rules and modified by the differences between coupler prescription targets and coupler performance of the actual hearing aids. With the subject wearing each hearing aid coupled to an unvented earmold, continuous speech was presented in the sound field and measured, after amplification, in the ear canal. The match between observed and predicted levels of amplified speech indicated the validity of the VIOLA assumptions under examination. RESULTS: The match between predicted and observed levels was good for soft speech input levels. As speech input levels increased, the differences between observed and predicted levels also increased, with the largest differences seen for loud speech inputs. When differences were seen between observed and predicted levels, they were always in the direction of lower than predicted ear canal levels. The differences between observed and predicted levels were attributed to the effects of limiting, effects of compression ratio in wide range compression, the individual subject's field-to-microphone transfer function, and the subject's individual real-ear-to-coupler level difference. CONCLUSIONS: Ear canal speech levels were reasonably close to predicted values, and the deviations from predicted levels were plausibly accounted for by consideration of hearing aid performance. Thus, the approach used by the VIOLA procedure holds considerable promise for extending clinical control over the complex and interactive parameters of nonlinear hearing aids. The results of this study indicate that selection and fitting of hearing aids using the current VIOLA procedure usually will result in the generation of lower than predicted ear canal speech levels, especially for loud speech inputs. However, the accuracy of the procedure could be improved substantially by modification of the software to account for the effects of limiting and those of the compression ratio in systems with compression thresholds lower than the level of unamplified loud speech.

Ear Canal↗
PubMed1999

Predicting DSM-III-R disorders from the Youth Self-Report: analysis of data from a field study.

OBJECTIVE: To predict DSM-III-R diagnoses from Youth Self-Report (YSR) scores. METHOD: The Diagnostic Interview Schedule for Children Version 2.1c (DISC-2.1c) and YSR were administered to 289 homeless adolescents. Stepwise discriminant analysis identified YSR scales contributing to predictions of DSM-III-R disorders. Paper-and-pencil prediction rules based on YSR "borderline" or "clinical" scores were evaluated. RESULTS: Statistically significant discriminant functions for disruptive disorders, depressive disorders, manic disorders, attention-deficit hyperactivity disorder, schizophrenia, and posttraumatic stress disorder, each based on a unique pair of YSR scales, produced overall hit rates of 0.66 to 0.90. Paper-and-pencil predictions produced comparable results. The weakest overall predictions were for the disruptive behaviors; the best rule ("IF Aggressive OR Delinquent is at least borderline THEN predict oppositional defiant disorder or conduct disorder") produced a 0.72 hit rate. The strongest overall predictions were for schizophrenia; the best prediction rule ("IF [Thought Problems AND Delinquent are at least borderline] AND [at least one is clinical] THEN predict schizophrenia") produced a 0.87 hlt rate. CONCLUSIONS: While the success rates reported here are specific to this sample, it appears that the YSR has good ability to predict DSM-III-R diagnoses as determined by the DISC. Furthermore, it was demonstrated that categorical diagnoses can be treated as locations or cluster sectors in a multidimensional space.

Adolescent↗
PubMed2002

Computed tomography's ability to predict sacrifice of hypoglossal nerve at resection.

OBJECTIVE: To assess whether preoperative computed tomography (CT) scan can determine if the hypoglossal nerve (cranial nerve XII) will be sacrificed in floor-of-mouth, oral tongue, and tongue base tumor resections. STUDY DESIGN: Retrospective review. METHODS: Patients who underwent resection of floor-of-mouth, oral tongue, and tongue base tumors from 1990 to 1999 were identified. Preoperative CT scans were reviewed by a neuroradiologist. The postoperative status of cranial nerve XII was predicted to be "saved" or "sacrificed." Hypoglossal nerve "sacrifice" was predicted if the fat planes surrounding the takeoff of the proximal lingual artery were obliterated by tumor. The nerve was determined to be sacrificed or spared during resection by review of the operative report. RESULTS: Of the 45 patients, 14 tumors were predicted radiographically to involve the hypoglossal nerve. Twenty-seven of 31 nerves that were predicted to be saved were saved at the time of surgery. Seven of 14 nerves that were predicted to be sacrificed were sacrificed at the time of surgery. The sensitivity was 0.64 (95% confidence interval [CI], 0.35-0.86) with a specificity of 0.79 (95% CI, 0.70-0.87). The positive predictive value was 0.50 (95% CI, 0.27-0.68) with a negative predictive value of 0.87 (95% CI, 0.77-0.95). CONCLUSIONS: The ability to predict preoperatively whether a tumor can be resected without sacrificing the hypoglossal nerve would be an important factor in determining management of these tumors. The results indicate that CT scan accurately predicts the ability of the surgeon to spare the hypoglossal nerve (negative predictive value, 87%) with a specificity of 0.79.

Female↗
PubMed1999

Predictive capacity of carbamazepine pharmacokinetic parameters in a Portuguese outpatient population.

The individualization of anticonvulsant therapy regimens can contribute to the implementation of appropriate carbamazepine (CBZ) maintenance doses in epileptic patients. An accurate method for the prediction of concentrations based on a determination of parameters and serum concentrations could be of clinical relevance in the management of epilepsy. In this study, we retrospectively evaluated the predictive performance in an adult outpatient population of six different methods, representing six sets of CBZ pharmacokinetic parameters selected according to the literature using a Bayesian computer program (PKS System; Abbott Laboratories, Abbott Park, IL, USA). The study involved 50 patients with two or more available concentrations selected under several inclusion criteria. The patients were taking CBZ (between 200 and 1600 mg/d) in monotherapy or polytherapy regimens and had no hepatic or renal disease. Steady state concentrations were predicted according to the use of prior information and using one and two feedback patient concentrations. Accuracy and precision were assessed by mean prediction error (ME), mean squared prediction error (MSE) and root mean squared prediction error (RMSE). The analysis showed CL = 0.067 L/hour/kg and Vd = 1.19 L/kg as the most accurate and precise set of pharmacokinetic parameters, presenting the highest percentage of clinically acceptable estimates (error < 2 microg/mL). Additionally, predictions based on one measured feedback concentration were found to be more accurate and precise than prior population-based predictions; the use of two previous patient concentrations further improved predictive capacity but failed to show a significant difference when compared with predictions based on one measured feedback concentration. In conclusion, the adoption of the previously mentioned set of parameters as population estimates and the use of at least one feedback concentration through the Bayesian approach seems to be essential for a better CBZ use in clinical practice. Finally, despite the obtained results, we believe that the Portuguese pharmacokinetic parameter determination of antiepileptics should be carried out to improve the rationale and cost-effectiveness of anticonvulsant therapy.

Adolescent↗
PubMed2004

Using exposure prediction rules for exposure assessment: an example on whole-body vibration in taxi drivers.

BACKGROUND: It is often difficult and expensive to make direct measurements of an individual's occupational or environmental exposures in large epidemiologic studies. METHODS: In this study, we used information collected in validation studies to develop a prediction rule for assessing exposure in a study with no direct measurement. We established a prediction rule through mixed-effect modeling of direct measurement data and information on observable exposure predictors and their interactions. Specifically, we used 383 measures of whole-body vibration from 247 professional taxi drivers and attempted to quantify vibration exposures for individuals in a large study on low back pain. RESULTS: Using the "jackknife method," we found that our prediction rule had an acceptably low relative prediction error of 11% (95% confidence interval-10-12%). Implementing the prediction rule would result in measurement errors independent of low back pain and of all identified and observable predictors of whole-body vibration. We applied the predicted levels to compute each person's daily exposure, and found a strong association between the predicted daily whole-body vibration exposure and prevalence of low back pain. This supported the construct validity of the exposure prediction rule. CONCLUSIONS: The predictive and construct validity of our prediction rule suggests that this general statistical approach can be useful in other occupational settings to improve the quality of exposure assessment.

Adult↗
PubMed2005

Prediction of small for gestational age by logistic regression in twins.

BACKGROUND: Small for gestational age (SGA) is one of the major determinants of perinatal mortality and morbidity, and may relate in adult diseases. Early prediction of SGA could be helpful for health care providers and public health workers in guiding antenatal management and prevention. The reported methods of SGA prediction are not satisfactory because the diagnostic performance is poor and the interval between prediction and delivery is too short. AIMS: To establish a SGA prediction model for twin pregnancies based on variables obtainable in early gestation. METHODS: We used a large twin registry United States data (1995-1997). The study subjects were randomly divided into two groups: group 1 to establish the prediction model by logistic regression and group 2 to validate the prediction model. SGA was defined as birth weight for gestational age z scores less than 10th percentiles. Pair of twin was the unit of analysis. Two sets of multiple logistic regression analyses with different outcome measures - one or both twins SGAs and both twins SGAs - were used to establish the prediction model. RESULTS: The sensitivity, specificity, and positive predictive value were 52.3, 62.5, and 21.5%, respectively, at the cutoff value 0.16 in a SGA prediction model based on maternal race, education, marital status, parity, prenatal care visit initiation, cigarette smoking, and paternal race. CONCLUSIONS: A prediction model based on determinants that can be obtained at early gestation might be useful in the management of pregnancies with high risk of SGA in twins.

Adult↗
PubMed1997

Predictive value of clinical indices in detecting aspiration in patients with neurological disorders.

OBJECTIVES: (1) To evaluate the predictive value of a detailed clinical screening of aspiration in patients with neurological diseases, both with and without symptoms of dysphagia taking videofluoroscopy as the gold standard; (2) to assess the existence of risk factors for silent aspiration, measuring the cost-benefit ratio of radiological examination. METHODS: 93 consecutive patients meeting the diagnostic criteria for a neurological disease with a risk of swallowing dysfunctions (cerebrovascular accidents, brain injury, Parkinson's disease, multiple sclerosis, amyotrophic lateral sclerosis, myotonic dystrophy, and abiotrophic diseases) underwent a detailed clinical assessment using a 25 item form to check for symptoms of dysphagia and impairment of the oropharyngeal swallowing mechanism. The 3 oz water swallow test was also performed to assess the aspiration risk. Sensitivity, specificity, positive predictive, and negative predictive values (NPV) of dysphagia, history of cough on swallowing, and 3 oz test positivity, versus videofluoroscopy documented aspiration, taken as the gold standard, were measured in all the patients and in subgroups with different neurological disorders. RESULTS: Non-specific complaints of dysphagia showed a very poor predictive value, whereas the symptom "cough on swallowing" proved to be the most reliable in predicting the risk of aspiration, with 74% sensitivity and specificity, 71% positive predictive, and 77% negative predictive value. The standardised 3-oz test had a higher predictive potential than the clinical signs, but had low sensitivity. The association of cough on swallowing with the 3 oz test gave a positive predictive of 84%, and an negative predictive value of 78%. In cases where the clinical tests failed to detect any impairment, videofluoroscopy documented only a low risk (20%) for mild aspiration. CONCLUSIONS: The association of two clinical items (such as history of cough on swallowing and 3 oz test positivity) provides a useful screening tool, the cost:benefit ratio of which seems very competitive in comparison with videofluoroscopy in aspiration risk evaluation.

Adolescent↗
PubMed2000

Value of somatosensory and motor evoked potentials in predicting arm recovery after a stroke.

OBJECTIVES: Prediction of motor recovery in the arm in patients with stroke is generally based on clinical examination. However, neurophysiological measures may also have a predictive value. The aims of this study were to assess the role of somatosensory (SSEPs) and motor (MEPs) evoked potentials in the prediction of arm motor recovery and to determine whether these measures added further predictive information to that gained from clinical examination. METHODS: Sixty four patients who had had a stroke and presented with obvious motor deficit of the arm were examined in terms of three clinical variables (motor performance, muscle tone, and overall disability) and for SSEPs and MEPs. Clinical and neurophysiological examinations were done at entry to the study (2 to 5 weeks poststroke), and at about 2 months after stroke. Further clinical follow up was conducted at 6 and 12 months after stroke. RESULTS: Neurophysiological measures made in the acute phase were of little use alone in predicting motor recovery of the arm at 2, 6, and 12 months after stroke. At 2 months, the absence of SSEPs and MEPs indicated a very poor outcome. Conversely, if the responses were preserved, a great variation in motor outcome was found. Multiple regression analysis showed that the addition of SSEPs and MEPs to the clinical examination increased the possibility of predicting arm recovery in the long term. In the acute phase, the combination of the motor score and SSEPs were best able to predict outcome. The long term outcome based on variables taken at 2 months, was best predicted through incorporating the three clinical measures and MEPs. CONCLUSIONS: Neurophysiological measures alone are of limited value in predicting long term outcome. However, predictive accuracy is substantially improved through the combined use of both of these measures and clinical variables.

Analysis of Variance↗