Mixed Amphetamine Salts Extended Release Improves Speed And Accuracy Of Information Processing In Adults With ADHD Reports The Washington Neuropsychological Institute
Published: May 24, 2006
TORONTO, May 24 /PRNewswire/ -- Mixed amphetamine salts extended release (MAS XR) substantially improved the speed and accuracy in information processing of adults with attention-deficit/hyperactivity disorder (ADHD), according to a study presented today at the annual American Psychiatric Association Meeting in Toronto, Canada.
"ADHD affects cognitive functioning -- how people process information -- and can interfere with the efficiency of completing tasks primarily due to the deficits in attention and executive functions," said investigator Gary Kay, Ph.D., president of the Washington Neuropsychological Institute. "Our analyses demonstrate that mixed amphetamine salts help people with ADHD to respond to a number of demanding cognitive tasks with more speed and accuracy."
In this study, participants started taking mixed amphetamine salts extended release or placebo for three weeks and were then switched to the other treatment while being evaluated by the same battery of tests. In a study of 14, participants who took MAS XR performed significantly better than those taking placebo on four variables, demonstrating improvements in divided attention, visuospatial working memory, visual scanning and tracking, and mental flexibility.
Assessment of cognitive functioning was conducted with the computer- administered CogScreen - Aeromedical Edition test, a test battery originally developed under contract to the Federal Aviation Administration for evaluating pilots. This validated test battery assesses visual and auditory attention and includes measures of working memory, information processing speed, mental flexibility, and divided attention. CogScreen is used by airlines as a predictor of flight performance and by biomedical researchers investigating the beneficial or adverse effects of medications on neurocognitive functioning.
"One unexpected finding was that patients who received mixed amphetamine salts extended release in the first treatment period and who were then switched to placebo for the second treatment period either maintained or improved their accuracy and response speed despite no longer receiving the medication," said Dr. Kay. "This finding suggests some lasting effects of psychostimulant treatment on certain aspects of neurocognitive processing in young adults with ADHD, underscoring the importance of treating ADHD early and appropriately," continued Kay.
Example: CogScreen Matching to Sample Test
Participants given a placebo before switching to mixed amphetamine salts extended release improved the accuracy of their responses (mean scores improved from 92.64 percent correct to 97.16 percent correct) on the Matching to Sample Test. This is a visual-spatial working memory test that requires participants to remember a checkerboard pattern and then identify that pattern after a brief delay. Patients given MAS XR in the first treatment period performed better than those receiving placebo (95.16 percent correct) and appeared to largely maintain this accuracy when taking placebo (94.32 percent correct).
This improvement in accuracy with MAS XR was paralleled by improvements in response speed. Patients receiving placebo in the first treatment phase had a mean response speed of 1.17 seconds. Their response speed improved to 1.04 seconds when taking MAS XR. Patients who received MAS XR in the first treatment phase demonstrated good response speed (1.07 seconds) and maintained their rapid response times when switched to placebo (1.06 seconds).
Additional Study Information
Investigators evaluated 17 adult participants, aged 19 to 25, in this six-week, double-blind, placebo-controlled, randomized two-way cross-over study. Neurocognitive results are based on 14 completers. Subjects were administered the CogScreen test battery twice during screening to become familiar with the cognitive tasks. At the completion of each 3-week treatment phase they were administered the CogScreen test battery four times; at 0 hours, 2 hours, 7 hours and 12 hours post-dose. When treated with MAS XR, participants received 20 milligrams (mg) daily during week one, followed by 40 mg/day during week two and 50 mg/day during week three.
MAS XR was well tolerated in the study. Thirty days after the final dose of MAS XR, participants received a follow-up phone call inquiring about any new-onset and serious adverse events.
Shire US Inc. supported this study.
About Washington Neuropsychological Institute
The Washington Neuropsychological Institute (WNImail@aol.com) is a private, independent research organization that conducts clinical research trials and provides consulting services to government agencies and to the pharmaceutical industry. At their Northwest Washington, DC facility WNI has conducted studies on antihistamines, anticholinergics, memory enhancement drugs, jet lag remedies, head trauma, epilepsy, diabetes, Parkinson's Disease, Alzheimer's Disease, and ADHD. WNI is fully equipped to support Phase III and Phase IV clinical trials. The institute specializes in computer-based neurocognitive testing and driving simulation. In addition, professional staff members are frequent lecturers at national and international medical and scientific meetings.
ADHD is a neurological brain disorder that manifests as a persistent pattern of inattention and/or hyperactivity-impulsivity that is more frequent and severe than typically observed in individuals at a comparable age and maturity level. Because everyone shows signs of these behaviors at times, the behaviors must appear early in life (before age 7 years) and continue for at least six months, according to the ADHD diagnosis criteria as defined in the American Psychiatric Association's Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition, Text Revision (DSM-IV-TR(R)). Up to 65 percent of children with ADHD may still exhibit symptoms into adulthood. In fact, approximately eight million American adults currently struggle with the inattention, impulsivity and hyperactivity symptoms of ADHD.
Without an effective treatment program, the symptoms of ADHD may lead to potentially serious consequences. A survey has shown that when compared to adults without ADHD symptoms, adults with untreated ADHD were more than twice as likely to have been arrested, 47 percent more likely to have received more than one speeding ticket in the last year, twice as likely to have been divorced and twice as likely to have held six or more jobs in the past decade. Further, evidence suggests that many adults with untreated ADHD may be at risk for other problems, including poor performance in the workplace and poor self-image.
Although there is no cure for ADHD, physicians and advocates are finding ways to help people with the condition learn to adapt to their school, home, social and work settings. ADHD usually can be successfully managed with behavioral therapy, structured coping techniques and medication. Psychostimulant medications are thought to stimulate areas of the brain that control attention, impulses, and self-regulation of behavior, remain among the most successful treatments for people with ADHD. Up to 70 percent of children with ADHD respond positively to psychostimulants. Medication should be considered part of an overall multi-modal treatment plan for ADHD.
"Effect of Mixed Amphetamine Salts Extended Release on Neurocognitive Speed in Young Adults with ADHD." Kay, Gary G. Ph.D. and Kardiasmenos, Katrina S. Ph.D.
"Effect of Mixed Amphetamine Salts Extended Release on Neurocognitive Accuracy in Young Adults with ADHD." Kay, Gary G. Ph.D. and Kardiasmenos, Katrina S. Ph.D.Washington Neuropsychological Institute
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