Paul S. Marshall

Effects of seasonal allergic rhinitis on selected cognitive abilities

BACKGROUND Many allergy patients complain of slowed thinking, memory problems, and difficulty sustaining attention during their allergy seasons. OBJECTIVE This study evaluated the effect of symptomatic allergic rhinitis on speed of cognitive processing, ability to divide and sustain attention, working memory, and recent verbal memory. METHODS Symptomatic ragweed-allergic rhinitis patients and nonatopic control subjects did cognitive testing in, out of, and in ragweed seasons. RESULTS Test results indicate that, during ragweed seasons, allergic patients experience subtle slowed speed of cognitive processing but not deficits in attention and recent memory. Some patients also have difficulties in working memory. CONCLUSIONS These findings suggest that having allergic reactions to ragweed pollen causes significant cognitive difficulties in a subgroup of patients.

Reliable Digit Span: a systematic review and cross-validation study.

Reliable Digit Span (RDS) is a heavily researched symptom validity test with a recent literature review yielding more than 20 studies ranging in dates from 1994 to 2011. Unfortunately, limitations within some of the research minimize clinical generalizability. This systematic review and cross-validation study was conducted to address these limitations, thus increasing the measure’s clinical utility. Sensitivity and specificity rates were calculated for the ≤6 and ≤7 cutoffs when data were globally combined and divided by clinical groups. The cross-validation of specific diagnostic groups was consistent with the data reported in the literature. Overall, caution should be used when utilizing the ≤7 cutoff in all clinical groups and when utilizing the ≤6 cutoff in the following groups: cerebrovascular accident, severe memory disorders, mental retardation, borderline intellectual functioning, and English as a second language. Additional limitations and cautions are provided.

Effectiveness of symptom validity measures in identifying cognitive and behavioral symptom exaggeration in adult attention deficit hyperactivity disorder

This study examines the effectiveness of symptom validity measures to detect suspect effort in cognitive testing and invalid completion of ADHD behavior rating scales in 268 adults referred for ADHD assessment. Patients were diagnosed with ADHD based on cognitive testing, behavior rating scales, and clinical interview. Suspect effort was diagnosed by at least two of the following: failure on embedded and free-standing SVT measures, a score > 2 SD below the ADD population average on tests, failure on an ADHD behavior rating scale validity scale, or a major discrepancy between reported and observed ADHD behaviors. A total of 22% of patients engaged in symptom exaggeration. The Word Memory test immediate recall and consistency score (both 64%), TOVA omission errors (63%) and reaction time variability (54%), CAT-A infrequency scale (58%), and b Test (47%) had good sensitivity as well as at least 90% specificity. Clearly, such measures should be used to help avoid making false positive diagnoses of ADHD.

Double-blind placebo-controlled study of the efficacy of oral terfenadine in the treatment of chronic fatigue syndrome

BACKGROUND There is no established treatment for chronic fatigue syndrome (CFS), an illness characterized by disabling fatigue exacerbated by physical activity. A variety of immunologic abnormalities have been reported, including a high incidence of atopy and hypoergy or anergy. OBJECTIVE Because of anecdotal reports and uncontrolled trials showing antihistamine efficacy in CFS, we evaluated the clinical efficacy of the antihistamine terfenadine (60 mg twice daily) in a placebo-controlled study. METHODS Thirty patients with CFS were enrolled in a 2-month, double-blind, placebo-controlled trial of terfenadine. Participants underwent a battery of both immediate- and delayed-type hypersensitivity skin tests and completed a self-assessment questionnaire used to measure severity of symptoms, physical and social functioning, health perceptions, and mental health before each of six biweekly visits. RESULTS Twenty-eight patients completed the trial. History of atopy and positive immediate skin test results were prevalent, 73% and 53%, respectively. No evidence for hypoergy or anergy after delayed-type hypersensitivity skin testing was found. No therapeutic benefit from terfenadine could be detected in terms of symptom amelioration, improved physical or social functioning, health perceptions, or mental health. A high incidence of atopy in patients with CFS was confirmed. CONCLUSION Although this trial involved a small number of patients, the results suggest that terfenadine is unlikely to be of clinical benefit in treating CFS symptoms.

Evaluation of the Appropriateness of Multiple Symptom Validity Indices in Psychotic and Non-Psychotic Psychiatric Populations

Although it is recognized that significant cognitive deficits are inherent in many psychiatric disorders, there is minimal research on whether the deficits can cause a failing score on symptom validity tests (SVTs). The performances of 104 and 178 patients with psychotic disorders and non-psychotic psychiatric disorders, respectively, on seven SVTs were examined. Analyses indicate that most of these SVTs have specificity rates of 90% or better for both clinical groups. Further, only 7% of patients in the psychotic group and 5% of patients in the non-psychotic psychiatric group produced false-positive classifications based on malingering criteria similar to those suggested by Slick et al. (i.e., failure of two or more SVTs or failure of one SVT at statistically significantly worse than chance rates). Consequently this research indicates that psychiatric disorders typically do not adversely affect SVT performance.

The Performance of Individuals with Mental Retardation on Cognitive Tests Assessing Effort and Motivation

The purpose of this study was to determine which tests of effort and motivation would be appropriate for use with patients with mental retardation when feigning of cognitive deficits is suspected. The seven measures evaluated included the WMS-III Rarely Missed Index Test, forced-choice recognition portion of the California Verbal Learning Test-II, Reliable Digit Span test, Rey 15-Item Test, Rey Dot Counting Test, the Rey 15-Item Test with Recognition Trial, and the Vocabulary (V)-Digit Span (DS) difference score. Results indicated that the forced-choice portion of the CVLT-II, the V-DS difference score, and the Rarely Missed Index Test from the WMS-III might be appropriate for use with this population with passing rates of 89%, 98%, and 91% respectively.

Validation Of The Sentence Repetition Test As A Measure Of Suspect Effort

It has been suggested that the Sentence Repetition Test (SRT) could serve as an adequate embedded symptom valid ity measure identifying suspect effort during neuropsychological testing. However, very little research has examined sensitivity and specificity rates when using this measure in a variety of clinical settings. The SRT was administered to 1031 patients referred for neuropsychological assessment in outpatient, inpatient, and independent medical evaluation settings. These patients were diagnosed with a wide range of psychiatric, developmental, and neurological disorders. The results of this study reveal that the SRT is a valid measure of suspect effort for the vast majority of these patients (sensitivity = 56.8% and specificity = 95.8% in combined clinical settings). However, analyses also indicate that the SRT is not a valid effort measure for individuals with mental retardation or dementia due to specificity rates falling well below 90% for both groups. Furthermore, the validity of the SRT as an effort measure is questionable for individuals with English as a second language, with a verbal learning disability, with a left cerebrovascular accident, or with an expressive-receptive language disorder due to small sample sizes or borderline specificity rates. Sensitivity, specificity, positive predictive accuracy, and negative predictive accuracy rates are provided for varying cutoff scores in inpatient, outpatient, and IME settings. The results of this extensive study confirm that the SRT can be a useful measure in detecting suspect effort in neuropsychological testing while also providing valuable clinical information.