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Biomedical subjects

Daniel J Cox

Publications and source records attributed to Daniel J Cox.

At least 19 recordsLinked to original sources
PubMed2006

Effect of extended release stimulant-based medications on neuropsychological functioning among adolescents with Attention-Deficit/Hyperactivity Disorder.

Attention-Deficit/Hyperactivity Disorder (ADHD) is associated with diminished neuropsychological functioning. This randomized, double-blind, placebo controlled, study is the first comparison of two extended release stimulant-based medications (Adderall XR and Concerta) and placebo on ADHD neuropsychological functioning. Adolescents diagnosed with ADHD (n=35, 19 males) completed three separate assessments (5, 8, 11 p.m.) on three different days and medications (Concerta, Adderall XR and Placebo). The assessments consisted of two different neuropsychological tests, the Delayed Matching-to-Sample and the Go/No-go (GNG), which measure visual memory, attention span, and response inhibition. Results indicated a significant effect of medication on signs of impulsivity and memory. Simple contrasts showed significant improvement in neuropsychological functioning (as measured by commission errors, reaction time, and recall accuracy) when participants were taking Concerta as opposed to placebo. These results suggest that Concerta impacts not only symptomatic behaviors but also cognitive functioning, which has implications for both academic performance and daily functioning.

Adolescent↗
PubMed2006

A novel analytical method for assessing glucose variability: using CGMS in type 1 diabetes mellitus.

BACKGROUND: Marked blood glucose (BG) fluctuations may increase the risk of some complications associated with diabetes. Acute BG excursions are common in patients with diabetes, but are not usually quantified, nor can they be captured by glycosylated hemoglobin level. This study evaluated the sensitivity of novel analytical methods for assessing BG variability using CGMS (Medtronic Minimed, Northridge, CA) data from patients treated with pramlintide, a drug that acutely reduces postprandial hyperglycemia when added to insulin therapy. METHODS: Retrospective analyses were done on 24-h CGMS profiles obtained from 22 evaluable subjects with type 1 diabetes using insulin pumps and receiving preprandial three times daily injections of placebo (n = 6) or 30 microg of pramlintide (n = 16) for 4 weeks. CGMS data were recorded at baseline, after 4 weeks of treatment, and after 2 weeks off-treatment. Three parameters were calculated for each time period: variability (BG rate of change), an index for severe hypoglycemia [low BG index (LBGI)], and an index for marked hyperglycemia [high BG index (HBGI)]. RESULTS: The mean postprandial BG rate of change was significantly lower after 4 weeks of pramlintide treatment compared with placebo treatment (0.87 vs. 1.21 mg/dL/min, P < 0.01) without changes in average glycemia, illustrating the sensitivity of this parameter to medication effects. The HBGI and LBGI indicated a decreased risk of hyperglycemia without a significant increase in risk of hypoglycemia after 4 weeks of pramlintide. CONCLUSIONS: These results suggest the potential utility of several novel methods for assessing variability and glycemic extremes to gauge the effects of pharmacological interventions not captured by glycosylated hemoglobin.

Adult↗
PubMed2006

Does "stubbornness" have a role in pediatric constipation?

The objective of this study was to determine if children with constipation are more stubborn, both in general and specifically regarding toileting behaviors, than children without constipation. A secondary objective was to determine if constipated children who are more stubborn are less likely to respond to routine therapeutic interventions than less stubborn constipated children. One hundred one children aged 2 to 6 years, who were first-time presenters (never received treatment) to their primary care physician (PCP) with constipation, were compared with 84 nonconstipated control children of similar age range. Comparison measures included general stubbornness and toilet-specific stubbornness (active resistance to participating in appropriate toileting behaviors). Measures of stubbornness were generated from retrospective questionnaires, prospective toileting diaries completed by the parents, and direct experimenter observations. The constipated children were treated by their PCP for 2 months and then reassessed. Constipated children were perceived by their parents to be significantly more stubborn than control children generally and specifically in terms of toileting. Some study evidence suggested that constipated children who continued to have difficulties after 2 months of treatment by their PCPs were perceived by their parents to have significantly more general stubbornness than constipated children who responded to treatment. Parent-perceived toilet-specific stubbornness significantly improved after successful treatment of the constipation by their PCP. The finding that constipated children had more parent-perceived stubbornness than children without constipation is notable because it may play a role in the development and/or maintenance of this bowel dysfunction as well as being an obstacle in treatment compliance.

Adult↗
PubMed2006

Predictors of fear of hypoglycemia in adolescents with type 1 diabetes and their parents.

OBJECTIVES: This study tested the hypothesis that both trait anxiety and hypoglycemic history contribute to fear of hypoglycemia (FOH) both in adolescents with type 1 diabetes mellitus (T1DM) and in their parents, and relationships between FOH and other variables including metabolic control, symptom perception, and use of insulin pump therapy. STUDY DESIGN: Thirty-nine parent-adolescent pairs completed questionnaires assessing background and clinical information, hypoglycemic episodes, FOH, and trait anxiety. Adolescent blood was also sampled for glycosylated hemoglobin A1c (HbA1c) measurement. RESULTS: In adolescents, both trait anxiety and frequency of severe hypoglycemic episodes were significant predictors of FOH, together accounting for almost 50% of the variance. Parental FOH was not predicted by their own trait anxiety or their child's hypoglycemic history but by whether they believed that their child carried emergency glucose. FOH was not related to metabolic control, although adolescents who experienced recent severe hypoglycemia (SH) with unconsciousness had significantly higher HbA1c. Parental trait anxiety significantly correlated with child trait anxiety, but parent-child levels of FOH were unrelated. Neither trait anxiety nor FOH related to reported symptoms, and FOH was not lower in parents with insulin pump therapy. CONCLUSIONS: Consistent with findings from adult patient populations, trait anxiety levels and recent experiences with hypoglycemia predict FOH in adolescents with T1DM. In parents, however, beliefs about their adolescents' ability to cope with hypoglycemic episodes predicted FOH. FOH in adolescents with T1DM and their parents is a complex construct influenced by multiple personality and situational and behavioral factors, and its impact on diabetes management remains unclear.

Adolescent↗
PubMed2006

Manual transmission enhances attention and driving performance of ADHD adolescent males: pilot study.

OBJECTIVE: Inattention is a major contributor to driving mishaps and is especially problematic among adolescent drivers with ADHD, possibly contributing to their 2 to 4 times higher incidence of collisions. Manual transmission has been demonstrated to be associated with greater arousal. This study tests the hypotheses that manual transmission, compared to automatic transmission, would be associated with better attention and performance on a driving simulator. METHOD: Ten adolescent drivers with ADHD practice driving on the simulator in the manual and automatic mode. Employing a single-blind, cross-over design, participants drive the simulator at 19:30 and 22:30 hr for 30 min in both transmissions and rate their attention to driving. RESULTS: Subjectively, participants report being more attentive while driving in manual transmission mode. Objectively, participants drive safer in the manual transmission mode. CONCLUSION: Although in need of replication, this pilot study suggests a behavioral intervention to improve driving performance among ADHD adolescents.

Accidents, Traffic↗
PubMed2006

Relative benefits of stimulant therapy with OROS methylphenidate versus mixed amphetamine salts extended release in improving the driving performance of adolescent drivers with attention-deficit/hyperactivity disorder.

OBJECTIVE: Automobile accidents are the leading cause of death among adolescents, and collisions are 2 to 4 times more likely to occur among adolescents with attention-deficit/hyperactivity disorder. Studies have demonstrated that stimulants improve driving performance. This study compared 2 long-acting stimulant medications during daytime and evening driving evaluations. METHODS: Adolescent drivers with attention-deficit/hyperactivity disorder were compared on a driving simulator after taking 72 mg of OROS methylphenidate, 30 mg of mixed amphetamine salts extended release, or placebo in a randomized, double-blind, placebo-controlled, crossover study design. During laboratory testing, adolescents drove a driving simulator at 5:00 pm, 8:00 pm, and 11:00 pm. Driving performance was rated by adolescents and investigators. RESULTS: The study included 35 adolescent drivers with attention-deficit/hyperactivity disorder (19 boys/16 girls). The mean age was 17.8 years. The overall Impaired Driving Score demonstrated that OROS methylphenidate led to better driving performance compared with placebo and mixed amphetamine salts extended release, whereas mixed amphetamine salts extended release demonstrated no statistical improvement over placebo. Specifically, relative to placebo, OROS methylphenidate resulted in less time driving off the road, fewer instances of speeding, less erratic speed control, more time executing left turns, and less inappropriate use of brakes. OROS methylphenidate and mixed amphetamine salts extended release worked equally well for male and female adolescents and equally as well with teenagers who have combined and inattentive subtypes of attention-deficit/hyperactivity disorder. CONCLUSIONS: This study validates the use of stimulants to improve driving performance in adolescents with attention-deficit/hyperactivity disorder. In the study, OROS methylphenidate promoted significantly improved driving performance compared with placebo and mixed amphetamine salts extended release.

Accidents, Traffic↗
PubMed2005

Treatment of childhood constipation by primary care physicians: efficacy and predictors of outcome.

OBJECTIVE: Childhood constipation accounts for 3% of visits to general pediatric clinics and as many as 30% of visits to pediatric gastroenterologists. The majority of children who experience constipation and whose caregivers seek medical care are seen by primary care physicians such as pediatricians or family physicians. Little is known about how primary care physicians treat childhood constipation or the success of their treatments. With this study, we prospectively examined which treatments primary care physicians prescribe to children who present for the first time with constipation and how effective those treatments are. METHODS: A total of 119 children who were between 2 and 7 years of age (mean: 44.1 +/- 13.6 months) and presented to 26 different primary care physicians (15 pediatricians and 11 family physicians) for the treatment of constipation for the first time participated in this study. Parents completed daily diaries of their child's bowel habits for 2 weeks before starting treatment recommended by their primary care physician and again 2 months after treatment. The prescribed treatment was identified by reviewing office records of the treating physicians. RESULTS: After 2 months of treatment, 44 (37%) of 119 children remained constipated. In the majority (87%) of cases, physicians prescribed some form of laxative or stool softener. The most commonly prescribed laxatives were magnesium hydroxide (77%), senna syrup (23%), mineral oil (8%), and lactulose (8%). In nearly all cases, a specific fixed dose of laxative was recommended; in only 5% of cases were parents instructed clearly to adjust the dose of laxative up or down to get the desired effect. In approximately half of the cases, physicians recommended some sort of dietary intervention. Some form of behavioral intervention was mentioned in the office records of approximately one third of cases; however, in most cases, little detail was provided. In 45% of cases, physicians prescribed disimpaction using oral cathartics, enemas, or suppositories followed by daily laxatives. In 35% of cases, physicians prescribed daily laxatives without any disimpaction procedure. In the remainder, physicians prescribed only dietary changes (5%), the use of intermittent laxatives (9%), or no therapy (7%). Treatment success corresponded to how aggressively the child was treated. Specifically, children who underwent some form of colonic evacuation followed by daily laxative therapy were more likely to have responded to treatment than were those who were treated less aggressively. CONCLUSION: Primary care physicians tend to undertreat childhood constipation. After 2 months of treatment, nearly 40% of constipated children remain symptomatic.

Cathartics↗
PubMed2005

Using the internet to provide information prescriptions.

INTRODUCTION: An information prescription is the provision of specific information to a patient on how to help manage a health problem. The Internet is being used increasingly as a source for information prescriptions, with clinicians directing patients to specific Web sites. As with any health care intervention, patients' lack of compliance is a barrier to the effectiveness of Web-based information prescriptions (WebIPs). WebIPs cannot be helpful if patients do not review the information prescribed for them. OBJECTIVE: The main objective of this study was to quantify the percentage of families who visit a Web site that was specifically prescribed by their physician. In addition, the use of an e-mail reminder was used to determine if it increases the likelihood that families will visit the prescribed Web site. Finally, barriers to accessing the prescribed Web site were identified. METHODS: Children were eligible if they presented to the pediatric gastroenterology clinic with chronic constipation and/or encopresis and their family had an active e-mail account and access to the Internet in their home. During their clinic visit, physicians instructed families to visit a Web site that provided educational information pertinent to their child's problem. Families were given a form with the Web-site address and a log-in identification number. Two days after their clinic visit, half of the families received an e-mail reminding them to visit the Web site. Families were contacted 1 week after their clinic visit to identify barriers to accessing the Web site. RESULTS: Eighty-three families participated in the study. Of the 83 families, 54 (65%) visited the prescribed Web site within 1 week of their clinic visit. Families who received e-mail reminders were significantly more likely to visit the Web site than families who did not receive an e-mail reminder (77% vs 53%). This difference could not be explained by the type or speed of Internet connection or how frequently they accessed the Internet or e-mail. The most common reasons that families cited for not accessing the Web site were "I forgot" and "I didn't have time." Few families cited technical reasons for not accessing the Web site. CONCLUSIONS: Almost two thirds of the families given a WebIP logged on to the prescribed Web site. The probability that families would access the site was increased by 45% with an e-mail reminder. Clearly, e-mail prompts improve compliance to WebIPs. As content and treatment programs continue to proliferate on the Web, it is important to identify barriers and solutions to them to improve overall compliance.

Adolescent↗
PubMed2005

Long-term benefits of prompts to use safety belts among drivers exiting senior communities.

Senior drivers are vulnerable to automobile crashes and subsequent injury and death. Safety belts reduce health risks associated with auto crashes. Therefore, it is important to encourage senior drivers to wear safety belts while driving. Using a repeated baseline design (AAB), we previously reported that motivating signs boosted safety belt usage by drivers exiting senior communities from baseline (72% and 68% usage), to postinstallation of signs (94%), to 6 months follow-up (80%). The current study was a 4-year follow-up in which six senior communities, with seat belt signs, were compared to six matched control senior communities with no signs. Safety belt usage was stable, across 4 years, at approximately 80% for both male and female drivers and front seat passengers for the six communities with signs, and was approximately 55% for control sites. These finding suggest that the simple and low-cost intervention of erecting signs to prompt safety belt use has persistent benefits that affect driver and passenger behavior alike.

Accidents, Traffic↗
PubMed2005

Relationships between hyperglycemia and cognitive performance among adults with type 1 and type 2 diabetes.

OBJECTIVE: Hyperglycemia is a common event among patients with type 1 and type 2 diabetes. While the cognitive-motor slowing associated with hypoglycemia is well documented, the acute effects of hyperglycemia have not been studied extensively, despite patients' reports of negative effects. This study prospectively and objectively assessed the effects of hyperglycemia on cognitive-motor functioning in subjects' natural environment. RESEARCH DESIGN AND METHODS: Study 1 investigated 105 adults with type 1 diabetes (mean age 37 years and mean duration of diabetes 20 years), study 2 investigated 36 adults with type 2 diabetes (mean age 50 years and mean duration of diabetes 10 years), and study 3 investigated 91 adults with type 1 diabetes (mean age 39 years and mean duration of diabetes 20 years). Subjects used a hand-held computer for 70 trials over 4 weeks, which required them to complete various cognitive-motor tasks and then measure and enter their current blood glucose reading. RESULTS: Hyperglycemia (blood glucose >15 mmol/l) was associated with slowing of all cognitive performance tests (P < 0.02) and an increased number of mental subtraction errors for both type 1 and type 2 diabetic subjects. The effects of hyperglycemia were highly individualized, impacting approximately 50% of the subjects. CONCLUSIONS: Acute hyperglycemia is not a benign event for many individuals with diabetes, but it is associated with mild cognitive dysfunction.

Adult↗
PubMed2004

Selective processing of food words during insulin-induced hypoglycemia in healthy humans.

RATIONALE: Hypoglycemia leads to undernutrition of the brain. Favoring selective processing of food stimuli would be an adaptive cognitive strategy. However, hypoglycemia is known to impair several aspects of cognitive function, and it is unknown whether selective cognitive processing of food stimuli occurs during insulin-induced hypoglycemia. METHODS: In a single-blind repeated measures design, healthy young adults (n=12, six female, mean age 28 years; mean body mass index 22.5 kg/m(2)) performed a standard Stroop word-color test, as well as a variant with food words designed to detect selective processing of food cues. Two sessions were scheduled with a 4-week interval. In each session, a hyperinsulinemic clamp method produced a normoglycemic (plasma glucose: 4.7 mmol/l) period, followed on 1 day by a hypoglycemic (2.7 mmol/l) testing period, and on the other day a second normoglycemic testing period (counterbalanced order). RESULTS: Color naming verbal reaction time (RT) increased during hypoglycemia (P<0.0001). The extent of the Stroop cognitive interference was independent of plasma glucose level. The key finding is that RT for food words increased more than for non-food control words (P<0.004), and this effect was not predicted by hunger ratings. CONCLUSIONS: Our data provide new evidence that during hypoglycemia, attention is directed selectively to food-relevant stimuli. The results are discussed in terms of adaptation.

Adaptation, Physiological↗
PubMed2004

Impact of methylphenidate delivery profiles on driving performance of adolescents with attention-deficit/hyperactivity disorder: a pilot study.

OBJECTIVE: Adolescents with attention-deficit/hyperactivity disorder (ADHD) are at high risk for driving accidents. One dose of methylphenidate (MPH) improves simulator driving performances of ADHD-diagnosed adolescents at 1.5 hours post-dose. However, little is known about the effects of different MPH delivery profiles on driving performance throughout the day. METHOD: This randomized, crossover, single-blind study compared osmotic, controlled-release oral system (OROS) MPH (Concerta) given q.d. to immediate-release MPH (Ritalin) given in equal doses t.i.d. on driving performance among six male ADHD-diagnosed adolescent drivers aged 16 to 19 years. Under each treatment condition, participants were maintained on their medication dosage for 7 days, then drove a sophisticated driving simulator at 2 p.m., 5 p.m., 8 p.m., and 11 p.m. The primary outcome measure was each participant's computer-quantified Impaired Driving Score (IDS). RESULTS: IDS worsened in the evenings for participants receiving MPH t.i.d. but remained stable when they received once-daily OROS MPH. Participants performed significantly better when receiving OROS MPH q.d. compared with MPH t.i.d. (F = 9.3, df = 1, p =.004). When MPH was given t.i.d., IDS significantly worsened beginning at 8 p.m. compared to OROS MPH (p =.01). CONCLUSIONS: Participants demonstrated significantly less variability and better driving performance when receiving OROS MPH q.d. compared to MPH t.i.d., particularly in the evenings.

Adolescent↗
PubMed2004

Hypoglycemia anticipation, awareness and treatment training (HAATT) reduces occurrence of severe hypoglycemia among adults with type 1 diabetes mellitus.

Severe hypoglycemia (SH) can be a significant problem for patients around the world with Type 1 Diabetes Mellitus (T1DM). To avoid SH, patients need to better manage, and reduce the occurrence of, preceding mild hypoglycemia. Hypoglycemia Anticipation, Awareness and Treatment Training (HAATT), developed in the United States specifically to address such issues, was evaluated at short- and long-term follow-up in a medically, economically and culturally different setting; Bulgaria. Sixty adults with T1DM and a history of recurrent SH (20 each from Sofia, Russe, and Varna, Bulgaria) were randomized to Self-Monitoring of Blood Glucose (SMBG) or SMBG+ HAATT. For 6 months before and 1 to 6 and 13 to 18 months after intervention, participants recorded occurrence of moderate, severe, and nocturnal hypoglycemia. For 1-month pre- and post-intervention, participants completed daily diaries concerning their diabetes management. Relative to SMBG, HAATT produced significant improvement in occurrence of low BG, moderate, severe, and nocturnal hypoglycemia, and detection and treatment of low BG (p values < .05 to < .001), with no compromise in metabolic control. At long-term follow-up, HAATT participants continued to have significantly fewer episodes of moderate and severe hypoglycemia. These findings suggest that a structured, specialized psycho-educational treatment program (HAATT) can be highly effective in managing hypoglycemia.

Adult↗
PubMed2004

Evaluating the accuracy of continuous glucose-monitoring sensors: continuous glucose-error grid analysis illustrated by TheraSense Freestyle Navigator data.

OBJECTIVE: The objective of this study was to introduce continuous glucose-error grid analysis (CG-EGA) as a method of evaluating the accuracy of continuous glucose-monitoring sensors in terms of both accurate blood glucose (BG) values and accurate direction and rate of BG fluctuations and to illustrate the application of CG-EGA with data from the TheraSense Freestyle Navigator. RESEARCH DESIGN AND METHODS: We approach the design of CG-EGA from the understanding that continuous glucose sensors (CGSs) allow the observation of BG fluctuations as a process in time. We account for specifics of process characterization (location, speed, and direction) and for biological limitations of the observed processes (time lags associated with interstitial sensors). CG-EGA includes two interacting components: 1) point-error grid analysis (P-EGA) evaluates the sensor's accuracy in terms of correct presentation of BG values and 2) rate-error grid analysis (R-EGA) assesses the sensor's ability to capture the direction and rate of BG fluctuations. RESULTS: CG-EGA revealed that the accuracy of the Navigator, measured as a percentage of accurate readings plus benign errors, was significantly different at hypoglycemia (73.5%), euglycemia (99%), and hyperglycemia (95.4%). Failure to detect hypoglycemia was the most common error. The point accuracy of the Navigator was relatively stable over a wide range of BG rates of change, and its rate accuracy decreased significantly at high BG levels. CONCLUSIONS: Traditional self-monitoring of BG device evaluation methods fail to capture the important temporal characteristics of the continuous glucose-monitoring process. CG-EGA addresses this problem, thus providing a comprehensive assessment of sensor accuracy that appears to be a useful adjunct to other CGS performance measures.

Adult↗
PubMed2003

Thermal biofeedback and lower extremity blood flow in adults with diabetes: is neuropathy a limiting factor?

Thermal biofeedback may be a useful adjunctive technique for enhancing cutaneous blood flow in patients with lower-extremity vascular complications of diabetes. However, autonomic, sensory, and/or motor neuropathies may impair vasomotion and limit the ability to alter blood flow and achieve significant foot warming with thermal biofeedback. We examined nerve function associated with four common types of diabetic neuropathy (sympathetic-autonomic, vagal-autonomic, sensory, and motor), hypothesizing that both sympathetic-autonomic and sensory neuropathies would limit the acquisition of biofeedback-mediated foot warming. Twenty-four participants with diabetes mellitus (19 with type II and 5 with type I) received a nerve conduction study and neurological evaluation of the upper and lower extremities. Hand temperature, foot temperature, and electrodermal gradient at the toes were monitored across six thermal biofeedback sessions. Participants were able to significantly raise p < .01) foot temperatures across sessions, an average of 2.2 degrees F. Consistent with our hypotheses, 41% of the variance in foot warming was explained by lower-extremity sympathetic-autonomic and sensory nerve function tests. This study demonstrated that a general diabetic population, including patients with mild-to-moderate neuropathy, can increase skin perfusion with thermal biofeedback. As hypothesized, lower-extremity sympathetic-autonomic and sensory neuropathies interfered with foot warming.

Adolescent↗
PubMed2003

An Internet intervention as adjunctive therapy for pediatric encopresis.

This study evaluated the benefits of enhanced toilet training delivered through the Internet for children with encopresis. Twenty-four children with encopresis were randomly assigned to the Internet intervention group (Web) or no Internet intervention group (No-Web). All participants continued to receive routine care from their primary care physician. The Web participants demonstrated greater improvements in terms of reduced fecal soiling, increased defecation in the toilet, and increased unprompted trips to the toilet (ps<.02). Both groups demonstrated similar improvements in knowledge and toileting behaviors. Internet interventions may be an effective way of delivering sophisticated behavioral interventions to a large and dispersed population in a convenient format.

Behavior Therapy↗