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Selective inhibition requires discrimination between auditory signals and is assessed using a modification of the stop-signal task. Selective inhibition was assessed in a group of 59 clinic-referred, DSM-IV-diagnosed children with attention-deficit hyperactivity disorder (ADHD) and compared to that of a community sample of 59 children. Methylphenidate (MPH) effects on selective inhibition were assessed in a subset of the ADHD sample that participated in an acute, randomized, placebo-controlled, crossover trial with 3 fixed doses of MPH. Children with ADHD performed more poorly than controls on the majority of selective stop-signal task parameters: they exhibited more anticipatory (invalid) responses, with less accurate and more variable responses on the response execution task, as well as a slower selective inhibition process. MPH improved speed of both inhibition and response execution processes; it also reduced variability of response execution and decreased nonselective inhibition. On the one hand, findings are consistent with purported inhibition deficit in ADHD, but on the other hand, suggest that neither the impairment itself, nor MPH effects, were restricted to inhibition.

Aims: To develop a model of prognosis for time receiving workers' compensation wage replacement benefits in the first year., Methods: A prospective cohort of 907 injured workers off work because of soft tissue injuries was followed for one year through structured telephone interviews and administrative data sources. Workers were recruited at workers' compensation claim registration. Only those still off work at four weeks post-registration were included in the analysis. Data from several domains (demographics, clinical factors, workplace factors, recovery expectations) were collected at approximately two weeks and a subset again at four weeks. Outcome was duration on total temporary wage replacement benefits. Variable selection was carried out in two steps using content experts and backward elimination with the Cox model., Results: Body region specific functional status, change in pain, workplace offers of arrangements for return to work, and recovery expectations were independently predictive of time on benefits. Change in pain and workplace offers interacted, so the largest mutual association occurred for those whose pain was getting worse-that is, reduction in median duration from 112.5 to 32.5 days. Across observed values, widely different recovery profiles of groups of workers resulted; for example, at four months, only one third of the highest risk group had gone off benefits while over 95% of the lowest risk group had done so., Conclusions: Focus on a relatively small set of prognostic factors should enable occupational health practitioners to triage injured workers within the first month and concentrate on those requiring additional assistance to return to work.

Background: Recent studies suggest that chiropractors continue to widely use radiography for assessing patients with acute low back pain. This practice is contrary to growing evidence that suggests only a small percentage of patients with acute low back pain require radiographic evaluation., Objectives: To assess quantitatively and qualitatively the views of chiropractors in a selected community in Ontario on the use of radiography for evaluating patients with acute low back pain., Study Design: Mailed surveys and focus group interview., Method: Surveys were mailed to all chiropractors (N = 26) in a selected community in Ontario, followed by a focus group session with local chiropractors (n = 7). Surveys requested information on personal and practice characteristics and the management of low back pain, including the use of radiography. The focus group, led by a facilitator, discussed issues surrounding practice guidelines and radiography use., Results: There was a 76% response rate to the mailed surveys. Of those who responded, 63% stated they would use radiography on patients with uncomplicated acute low back pain lasting 1 week; 68% stated that radiographs were useful in the diagnostic evaluation of patients with acute low back pain lasting less than 1 month. Most reasons given for use of radiography in this patient population are not supported by existing evidence., Conclusions: There appears to be a high rate of radiographic use by chiropractors in the study community, which is consistent with findings in previous studies. Many of the reasons given for use of radiography are not supported by existing evidence and may contribute to the gap between current chiropractic practice and available evidence with respect to use of radiography for acute low back pain.

Background: Rigorous evidence on factors affecting the prognosis of work-related soft-tissue injuries remains limited. Although shown to be important for a wide variety of clinical conditions, recovery expectations have rarely been assessed as prognostic factors for workers with soft-tissue injuries. We examined the predictive role of various measures of recovery expectations among workers with injuries resulting in time off work., Methods: We identified a prospective cohort of 1566 injured workers shortly after they filed a claim for their injury with the Ontario Workers' Compensation Board (OWCB). They had soft-tissue injuries to the back or upper or lower extremities, had new, lost-time claims from May to November 1993 and were still off work at the time of the first interview. We interviewed participants by telephone within 3 weeks after the injury and measured their recovery expectations (perceptions regarding progress, expected change in condition, expected time until return to usual activities and expectations regarding return to usual job) along with other, potentially important prognostic factors. The primary outcome was total time receiving 100% wage-replacement benefits during the year following injury, obtained from OWCB administrative files. Self-reported measures of pain, health-related quality of life and functional status, obtained up to 4 times during the year following injury, were both independent predictors and secondary outcomes., Results: The 4 measures of recovery expectations together explained one-sixth of the variation in time receiving benefits. All but expectations regarding return to usual job were individually predictive of time receiving benefits. Judging one's recovery as much better than expected resulted in a 30% (95% confidence interval [CI] 9%-46%) faster rate of stopping receiving benefits (and likely returning to work) compared with judging one's recovery as much worse than expected. Similarly, participants who expected to return to usual activities within 3 weeks had a 37% (95% CI 26%-47%) faster rate of stopping receiving benefits than those who responded "Don't know" to this question, and participants who stated that they were fully recovered or would get better soon had a 25% (CI 5%-40%) faster rate than those who thought they would never get or stay better. Positive recovery expectations were also associated with reductions in pain grade and improvement in functional status outcomes., Interpretation: Expectations regarding recovery may provide useful information on the complex process of recovering from work-related soft-tissue injuries. For clinicians, patients' negative or uncertain expectations may indicate the need for further probing and intervention on psychosocial factors to facilitate recovery.

The purpose of this study was to determine whether individual items in a disability questionnaire were answered differently depending on whether or not the questions were attributed to the upper limb (i.e., "do you have difficulty eating due to your arm or hand problem?" or "do you have difficulty eating?", respectively). The a priori hypothesis was that the same or more disability would be detected by nonattributed items. Four hundred sixty-seven patients with upper extremity disorders completed the SF-36 general health survey, which does not attribute health problems to affected areas. Patients also completed six additional questions, modified from the SF-36, regarding work (four questions) and social function with friends and family (two questions), which attributed their disability to their affected upper extremity. Of 467 patients, 419-431 (89-92%) responded to both versions of the questions. Although we demonstrated a significant order effect (Generalized Estimating Equation; P=.003), comparison of the responses to the six questions showed that for five of the six questions (Generalized Estimating Equation; P< or = .001) patients reported more disability when the questions were worded with attribution to the upper extremity. Even considering the order effect, patients demonstrated a counterintuitive result by reporting more disability when questions were attributed to their affected area. Thus, both the wording of questions and order of questions can significantly affect patients' responses about their disability and raises questions about the validity of patients' reports of their disability.

Study Objectives: To assess various sleep parameters in latency-aged children with ADHD and their normally developing peers through the use of multiple sleep measures., Design: Six sleep parameters were evaluated for two groups of children, ADHD and normal comparison. Each group consisted of 25 children (20 males, 5 females) who ranged in age from 7 to 11 years. All children underwent rigorous diagnostic procedures and the ADHD subjects were selected only if they displayed pervasiveness in their symptomatology and were medication naive. Parents completed a retrospective questionnaire which evaluated sleep problems over the past six months. Additionally, each child wore an actigraph for seven consecutive nights, and the child's parents completed a sleep diary during this time period., Setting: N/A., Patients or Participants: N/A., Interventions: N/A., Results: Based on the findings from the questionnaire, parents of children with ADHD reported significantly more sleep problems than parents of normally developing children. However, the majority of these sleep differences were not verified through actigraphy or sleep diary data, with the exception of longer sleep duration for children with ADHD and parent reports that describe increased bedtime resistence. It was also found that child-parent interactions during bedtime routines were more challenging in the ADHD group., Conclusions: Despite the possibility of intrinsic sleep problems such as longer sleep duration, results indicate that many of the sleep problems of children with ADHD may be due to challenging behaviours during bedtime routines. The reason for discrepancies among sleep studies employing objective measures as well as between retrospective and prospective measures are discussed.

Time-to-claim-closure is a common outcome in cohort studies of whiplash injuries. However, its relationship to health recovery is unknown. We investigated the association between neck pain, physical functioning, depressive symptomatology and time-to-claim-closure in a Saskatchewan cohort of 5398 whiplash claimants in 1994-1995. Participants were surveyed five times over 1 year. In 1995, the insurance system changed from tort to no-fault, eliminating compensation for pain and suffering. Under tort, a 10-point increase in pain reduced the claim-closure rate by 13-24% while a 10-point increase in physical functioning increased it by 17%. Depressive symptomatology reduced the claim-closure rate by 37%. Under no-fault, a 10-point increase in pain reduced the claim-closure rate by 18% while a 10-point increase in physical functioning increased it by 10-35%. The presence of depressive symptomatology reduced the claim-closure rate by 36%. The results suggests lower pain, better function and the absence of depressive symptoms are strongly associated with faster time-to-claim-closure and recovery after whiplash, independent of the insurance system.

Modified-work programs are designed to facilitate the return to work for employees with a work-related injury. Although extensive published literature exists that describes and evaluates "ideal" programs, to date there is a paucity of data describing practice. To address this pertinent issue, we administered a survey to a large sample of 1833 workers with soft-tissue injuries in Ontario, Canada, and asked them detailed questions about modified work and employer contact. Our results reveal that most workers (66%) were contacted by someone from their workplace to check on how they were doing. However, only a minority (36%) were offered arrangements by their employer to help them return to work after developing a work-related soft-tissue injury. Most arrangements that were offered to injured workers consisted of such temporary modifications as reduced hours (24%), flexible work hours (25%), or a lighter job (57%) rather than more permanent changes to the way that work is conducted, such as changes to the work layout or equipment (8%). Merely being contacted by the workplace to check on how the worker was doing was not associated with reduced compensation benefit duration. Workplace offers of arrangements to help the worker return to work were associated with reduced compensation benefit duration but were not statistically associated with workers' pain grade.

Study Design: Prospective inception cohort study., Objective: To develop a prognostic model that predicts time receiving workers' compensation benefits for low back pain claimants., Summary of Background Data: As the cost and difficulty of managing low back pain escalate, any predictor of outcome is advantageous., Methods: To obtain the outcome and predictor variables, patient data from two separate databases were linked: a clinical database and an administrative (Ontario workers' compensation) database. Claimants injured between January 1 and December 31, 1994, were included and observed for 1 year from the date of accident. The outcome variable was cumulative number of calendar days receiving benefits., Results: Multivariable Cox proportional hazards regression (forward stepwise) showed eight significant predictors; five were associated with increased time receiving benefits compared with their reference groups: 1) working in the construction industry, 2) older age, 3) lag time from injury to treatment, 4) pain referred into the leg, and 5) three or more positive Waddell nonorganic signs. Three predictors were associated with reduced time receiving benefits: 1) higher values of questionnaire score, 2) intermittent pain, and 3) a previous episode of back pain. A predictive score was calculated to categorize claimants as at high or low risk for chronicity. When an arbitrary cutoff point was set at the 75th percentile of predictive score, negative predictive value was 94%., Conclusion: This research identified eight factors for time receiving workers' compensation benefits among claimants with low back pain. This model discriminates between high- and low-risk claimants. Few low-risk claimants continued to receive benefits for more than 3 months.

Objective: To determine the relationship of sleep problems to attention-deficit/hyperactivity disorder (ADHD), diagnostic subtype, comorbid disorders, and the effects of stimulant treatment., Method: On the basis of clinical diagnostic interviews, children aged 6 to 12 years were assigned to 4 groups: unmedicated ADHD (n = 79), medicated ADHD (n = 22), clinical comparison (n = 35), and healthy nonclinical comparison (n = 36). These groups were compared on 2 sleep questionnaires completed by the parents that assessed current sleep problems and factors associated with sleep difficulties (i.e., sleep routines, sleep practices, child and family sleep history)., Results: Factor analysis revealed 3 sleep problem categories: dyssomnias, parasomnias, and sleep-related involuntary movements. Linear regression analyses showed that (1) dyssomnias were related to confounding factors (i.e., comorbid oppositional defiant disorder and stimulant medication) rather than ADHD; (2) parasomnias were similar in clinical and nonclinical children; and (3) the DSM-IV combined subtype of ADHD was associated with sleep-related involuntary movements. However, sleep-related involuntary movements were more highly associated with separation anxiety., Conclusions: The results suggest that the relationship between sleep problems and ADHD is complex and depends on the type of sleep problem assessed as well as confounding factors such as comorbid clinical disorders and treatment with stimulant medication.

Patients' ratings of the severity and importance of items are often used to select items for health status instruments. The purpose of this study was to compare six different methods of combining severity-importance ratings. Two different patient groups separately rated the importance and severity of their complaints; (i) 76 patients with upper-extremity disorders rated 70 upper-extremity-related questions; and (ii) 86 patients with hip arthrosis rated 22 questions relating to their hip problem. The rank ordering of the items using the six different methods in the two populations were very similar (tau(bi) = 0.91 and 0.87, respectively). Furthermore, the six methods when used to choose 30 upper-extremity items shared 25 items in common and shared 9 (of 10) hip items in the second group. In conclusion, the results of item reduction were not affected by the method of creating importance-severity ratings.

Clinimetrics and psychometrics, two accepted methods for developing multiitem health measurement scales, have fundamentally different aims and methods that have seldom been compared and never prospectively. The purpose of this study was to determine whether these two methodologies provided comparable scales in the development of an upper extremity disability measure. Psychometric analysis involved field testing a 70-item questionnaire on 407 patients. Equidiscriminatory item total correlation (EITC) was used to select the top 30 items. Clinimetric testing used the mean importance and severity ratings of the 70 items by 76 patients to select the top 30 items. Clinimetric and psychometric analyses were performed independently. Cronbach's alpha was 0.97 for the top 30 items selected by EITC and 0.96 for the items selected based on patient's ratings. The two scales (after clinician modification to improve face validity) shared 16 items in common (P=0.10). The intraclass correlation coefficient of the patient scores on the two 30-item scales was 0.93 before clinician input and 0.97 after. The mean (and standard deviation) difference between scales was 9.1 (8.8) before and 1.7 (5.2) after clinician input. A scale developed with a clinimetric strategy can measure a complex (so-called heterogeneous) clinical phenomenon (thought to be composed of several patient attributes) but still fulfill psychometric criteria for "homogeneity." Thus, these strategies for the development of health measurement scales, which have been considered potentially opposite or conflicting, may be complementary.

Despite the publication in the mid-1990s of comprehensive practice guidelines for the management of acute low-back pain, both in the United States and elsewhere, this ubiquitous health problem continues to be the main cause of workers' compensation claims in much of the Western world. This paper represents a synthesis of the intervention studies published in the last 4 years and is based on a new approach to categorizing these studies that emphasizes the stage or phase of back pain at the time of intervention and the site or agent of the intervention. Current thinking suggests that medical management in the first 3-4 weeks after the onset of pain should be generally conservative. Several studies of rather heterogeneous interventions focusing on return to work and implemented in the subacute stage (3-4 to 12 weeks after the onset of pain) have shown important reductions in time lost from work (by 30% to 50%). There is substantial evidence indicating that employers who promptly offer appropriately modified duties can reduce time lost per episode of back pain by at least 30%, with frequent spin-off effects on the incidence of new back-pain claims as well. Finally, newer studies of guidelines-based approaches to back pain in the workplace suggest that a combination of all these approaches, in a coordinated workplace-linked care system, can achieve a reduction of 50% in time lost due to back pain, at no extra cost and, in some settings, with significant savings.

Study Design: A prospective cohort of approximately 1600 injured workers off work because of soft-tissue musculoskeletal problems was followed for 1 year through a series of structured telephone interviews., Objective: To determine the effectiveness of a Workers' Compensation Board-sponsored early, active, exercise and education program based in the community in comparison to "usual" care., Summary of Background Data: The program established in 1990 was available in more than 100 clinics. Results from an earlier pilot study indicated lower overall claims costs for workers attending the program compared with non-attenders., Methods: Subjects were recruited at the time of Workers' Compensation Board claim registration. Routinely collected data and self-reported responses to demographic, quality-of-life, functional status, pain, recovery expectations, and workplace response to injury questions were used to determine selection factors for community clinic attendance. Economic and non-economic outcomes were compared for clinic attenders and non-attenders., Results: For the 885 male and female new back problem cases in the study, overall clinic attenders were not systematically different from non-attenders at baseline. Analysis of duration of benefits showed no significant difference between attenders and non-attenders, although health care costs for clinic attenders were significantly higher. Functional status, health-related quality-of-life, and pain measures all improved significantly throughout time for both groups, bit there were no statistically significant differences in rate of improvement., Conclusion: There was no advantage from the program compared with usual care on the outcomes measured-a finding consistent with recent studies that examined the longer-term effectiveness of other interventions in the first few weeks of back pain symptoms.

Objectives: To compare the measurement properties over time of five generic health status assessment techniques., Methods: Five health status measures were completed on two occasions by a sample of workers with musculoskeletal disorders. They included the SF-36, Nottingham Health Profile, Health Status Section of the Ontario Health Survey (OHS), Duke Health Profile, the Sickness Impact Profile and a self-report of change in health between tests., Setting: Subjects were accrued from a work site (within one week of injury) (n = 53), physiotherapy clinics (four weeks after injury), (n = 34), and a tertiary level rehabilitation center (more than four weeks after injury) (n = 40)., Analysis: Intraclass correlation coefficients (ICC) derived from nonparametric one-way analysis of variance were used for test-retest reliability in those who had not changed (n = 49). Various responsiveness statistics were used to evaluate responsiveness in those who claimed they had a positive change in health (n = 45) and in those who would have been expected to have a positive change (n = 79)., Results: Of the 127 subjects recruited, 114 completed both questionnaires (89.8%). In the subjects who reported no change in health, analysis of targeted dimensions (overall scores, physical function, and pain) demonstrated acceptable to excellent test-retest reliability in all but the Duke Health Profile. In subjects with change in health, the SF-36 was the most responsive measure (moderate to large effect sizes [0.55-0.97] and standardized response means ranging between 0.81 and 1.13)., Conclusions: The results suggest that the SF-36 was the most appropriate questionnaire to measure health changes in the population studied. The selection of a health status measure must be context-specific, taking into account the purpose and population of the planned research.

The purpose of this study was to compare the measurement properties of five generic health status measures in a cross-sectional study of injured workers. One hundred twenty-seven injured workers participated in the study. Forty-seven percent had disorders of the upper limb, 12% neck and upper back, and 27% lower back (14% unspecified). All participants completed a package containing: SF-36 (Acute), Nottingham Health Profile (NHP). Duke Health Profile (Duke). Health status section of the Ontario Health Survey (OHS), and the Sickness Impact Profile (SIP). Frequency distributions were examined, correlations carried out, and the ability to discriminate between part of body and overall health state evaluated using analysis of variance. The results showed a ceiling (healthy) effect in the OHS, NHP, and SIP. Correlations were moderate to good. Upper limb subjects appeared "healthier" than low back pain subjects. The instruments were able to discriminate between health states (p < 0.05) except the OHS-Physical function (p = 0.51). Different questionnaires give a different impression of health. Clinicians and researchers should be thoughtful in their selection of outcome measures as different instruments may alter the description, intervention, and priorization of a particular disorder.

A critical appraisal of existing classifications of soft tissue disorders of the neck and upper limb was performed utilizing methodological criteria including appropriateness for purpose, validity, reliability, feasibility, and generalizability. Five classifications were assessed independently by three raters using standardized forms. For those criteria that can be assessed by inspection of the classification itself, none of the classification systems appeared acceptable for reasons such as failure to be comprehensive, overlap of categories, and lack of demonstration that the criteria for inclusion into the categories are valid and reliable. No judgement could be passed about those criteria that require formal testing, such as reliability and construct validity, because of the absence of data. The overall interrater reliability of the critical appraisal was high, with an intraclass correlation coefficient of 0.82. The validity of studies that have relied upon existing classifications of soft tissue disorders of the neck and upper limb to group the entities under study is questioned in light of the findings of this study. Future work should be directed toward improving existing classification systems and/or developing new ones that fulfil basic measurement criteria.

Objective: Since both the incidence of lung cancer and the proportion of the population over age 65 are increasing rapidly in North America, we undertook a retrospective review of elderly patients with small cell lung cancer (SCLC) in an attempt to assess the effect of age on treatment decisions, response, survival, and toxicity., Design: Retrospective chart view., Setting: Oncology Unit of a university-affiliated teaching hospital., Patients: There were 123 patients age > 70 years treated from 1976-88. Chemotherapy consisted of either cyclophosphamide, doxorubicin, and vincristine, or etoposide and cisplatin., Results: There were 74 patients aged 70-74, 35 aged 75-80, and 14 aged 80 years or older. No significant differences existed between the groups in sex, stage, performance status, or presence of co-morbid disease. Median survivals for patients with limited and extensive disease were 11.9 and 5.2 months, respectively (P = < 0.0001), with no significant difference for patients in any age group (P = 0.4). For both limited and extensive disease, survival correlated strongly with the treatment received. Twenty-five patients received no treatment (median survival 1.1 months), 20 had radiation only (median 7.8 months), and 27 patients had < 3 cycles of chemotherapy (median 3.9 months). Median survival for the 50 patients who had 4-6 cycles was 10.7 months (limited disease 15.0 months, extensive disease 8.61 months). In the Cox Model, survival correlated strongly with stage of disease and chemotherapy treatment (P < 0.0001), but only marginally with performance status (P < 0.077). Of the 77 patients who had chemotherapy, less than 50% in all age groups completed six cycles. Only two patients completed chemotherapy without a single dose reduction, and 76.7% required more than two reductions., Conclusions: Chemotherapy should not be withheld from elderly patients with SCLC on the basis of age. The survival of patients who receive chemotherapy is significantly longer than that of untreated patients even though frequent dose reductions for toxicity may be required. The survival benefit is due to treatment effect and is not due to a selection bias in the cohort of patients chosen for therapy.

Perinatal factors related to the incidence of respiratory distress syndrome were analyzed by the multiple logistic regression statistical method in 263 mothers and their 298 offspring delivered between 24 and 35 weeks' gestation in a 1-year period in a regional referral perinatal center. The risk of respiratory distress syndrome in white infants rose with decreasing gestational age (p less than 0.0001) while prolonged rupture of membranes of greater than 24 hours in the absence of maternal infection (28% of cases) was highly protective (p less than 0.0001). Compared with vaginal delivery, cesarean delivery without labor increased the risk of respiratory distress syndrome (p = 0.03). The administration of tocolytic drugs was unrelated to the incidence of respiratory distress syndrome, but corticosteroid therapy given at least 72 hours before delivery was protective (p = 0.03). Male and female infants were equally at risk for respiratory distress syndrome as were black and white infants, but other races had a lower incidence (p = 0.004). Infants with respiratory distress syndrome were on mechanical ventilators longer than those with other respiratory illnesses.

A cohort of 61 patients with Kaposi's sarcoma (KS) and AIDS was seen in the Oncology Unit of the Toronto General Hospital between 1982 and 1986. In an attempt to identify prognostic variables, laboratory and clinical parameters were examined using Kaplan-Meier estimates and the Cox Regression Model. All patients were male, median age 36 years (range 23-52). In 49 patients KS was diagnosed before any AIDS-associated opportunistic infection (OI). Three patients had concurrent KS and OI, and nine patients developed KS one or more months after an OI. Only 11 patients had stage I or II disease, 34 stage III, and 15 stage IV. Only 18 patients (30%) were asymptomatic. Twenty-six percent had fever, night sweats, or weight loss, 11% had minor opportunistic infections, and 33% had both symptom complexes. The median overall survival was 10.5 months. The survival of patients who received chemotherapy for their KS was not significantly different from the survival of non-treated patients (p = 0.7). Although significant differences in survival could not be seen between stages, patients with both systemic symptoms and minor opportunistic infections had significantly shorter survival (p = 0.03). Survival from the onset of KS was significantly shorter for patients who had experienced a previous OI, but their overall survival from the date of diagnosis of AIDS was not significantly different from those patients presenting with KS alone. When analyzed separately the laboratory parameters of hemoglobin (p less than 0.0001), absolute lymphocyte count (p = 0.03), platelet count (p = 0.04), and T4 level (p = 0.05) demonstrated a significant relationship with survival.(ABSTRACT TRUNCATED AT 250 WORDS)