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John Gunstad

Publications and source records attributed to John Gunstad.

28 records · Page 2Linked to original sources
PubMed2005

Category and letter verbal fluency across the adult lifespan: relationship to EEG theta power.

The purpose of this study was to examine the impact of age, sex, and education on category and letter verbal fluency task performance. A secondary goal was to examine whether resting EEG theta power in bilateral frontal and temporal lobes impacts age-associated decline in verbal fluency task performance. A large sample (N = 471) of healthy, normal participants, age 21-82, was assessed for letter fluency (i.e., FAS), and for category fluency (i.e., Animal Naming), and with a 32-channel EEG system for 'eyes-open' resting theta power. The effects of age, sex, and education were examined using analyses of variance. Correlation analyses were used to test the impact of theta power on age and fluency performance by controlling for the effects of theta when examining the relationship between the other two variables. The results indicated that performance on both fluency tests declined linearly with age, but that the rate of decline was greater for category fluency. These age changes were not associated with education level, and there were no sex differences. While theta power was negatively associated with age and positively associated with Animal Naming performance, it did not moderate the relationship between the two. The differential age-associated decline between category and letter fluency suggests separate neurobiological substrates underlying the two domains of performance, which is not related to theta activity.

Adult↗
PubMed2005

Subcortical hyperintensities impact cognitive function among a select subset of healthy elderly.

Previous studies have examined the impact of subcortical hyperintensities (SH), a proxy measure of cerebrovascular disease, on the cognitive abilities of otherwise healthy older adults. However, there remains a limited understanding as to what extent this MRI marker of pathological processes explains the decline in specific cognitive functions that occur nearly ubiquitously with advanced age, especially in relation to other age-related imaging markers. In the present study we compared cognitive abilities between a sample of 53 older healthy adults (age range=50-79) and a sample of 53 younger adults (age range=21-40). As expected, the older group performed significantly worse on most cognitive measures compared to the younger group. Frontal volume and total grey matter volume were also significantly reduced among the older individuals compared to the younger individuals. SH volume was consistently associated with cognitive function in older adults, though, this relationship was evident only for a relatively small subset of older individuals with the most severe SH. These data suggest that the relationship between SH and cognition in the elderly is driven by a subset of individuals who may be in the earliest stages of vascular cognitive impairment. Further, the findings suggest that cognitive aging is largely determined by factors other than SH for most older adults.

Adolescent↗
PubMed2005

Further exploration of the effect of "diagnosis threat" on cognitive performance in individuals with mild head injury.

The present study further explored the phenomenon of "diagnosis threat" (Suhr & Gunstad, 2002), by examining the potential explanatory roles of anxiety, effort, and depression. Individuals with mild head injury history were randomly assigned to receive either neutral instructions (controls, N = 25) or to have attention called to their head injury history as a reason for invitation into the study (diagnosis threat, N = 28). Depression was measured at baseline. Following the neuropsychological battery, ratings of effort, test pressure, and state anxiety were completed. The diagnosis threat group performed worse than controls on attention/working memory, psychomotor speed, and memory tasks, but not on measures of executive functioning, post-test anxiety, or effort. Effort, anxiety and depression were not related to cognitive performance, nor did depression interact with expectations in explaining group differences in performance. Results provide further support for the "diagnosis threat" effect, but offer no support for effort, anxiety, or depression explanations for diminished performance.

Adolescent↗
PubMed2005

Blood pressure variability and white matter hyperintensities in older adults with cardiovascular disease.

The present study examined the relationship between multiple blood pressure (BP) indices and white matter hyperintensities (WMH) in a sample of 39 older adults with cardiovascular disease (CVD). Resting BP was measured using an automated monitor every 10 min for 2 h. WMH were quantified on FLAIR images and separate indices were generated for neocortical, periventricular and subcortical brain regions. Correlation analyses revealed systolic BP variability was related to neocortical and total WMH. A function of systolic BP variability and average diastolic pressure showed the strongest relationships, including significant correlation to neocortical, subcortical and total WMH. No BP index was related to WMH in periventricular regions. Exploratory analyses showed only the function of systolic BP variability and average diastolic pressure predicted total WMH, whereas as age, CVD conditions and psychosocial factors did not. These findings demonstrate BP variability is an important contributor to WMH in older adults with CVD and suggests it may have differential relationships to WMH in different brain regions. Additional studies are needed to examine the role of autoregulatory systems in the development of WMH, particularly those using beat-to-beat measures of BP.

Aged↗
PubMed2004

Cognitive factors in Postconcussion Syndrome symptom report.

Past studies suggest a variety of factors that influence the report of Postconcussion Syndrome (PCS) symptoms, including head injury, depression, pain, and subjective expectation. Participants included 190 undergraduates across 8 groups chosen to examine the relative contribution of these factors, as well as treatment-seeking behavior, in the report of both current and past PCS symptoms. Depressed persons, depressed persons receiving treatment, and headache sufferers receiving treatment reported elevated rates of PCS symptoms when compared to controls. Five of the eight groups reported experiencing more current than past symptoms. Head-injured persons and headache sufferers underestimated premorbid symptom rates relative to the baseline of controls. These findings are consistent with the growing number of studies that suggest non-neurologic factors may be more closely related to PCS symptom report than head injury status and raise further concern regarding use of self-reported PCS symptoms in the diagnosis of head injury.

Adolescent↗
PubMed2002

"Diagnosis Threat": the effect of negative expectations on cognitive performance in head injury.

The present study examined the effect of negative expectations on neuropsychological test performance. It was hypothesized that having attention called to a history of prior head injury and the potential effects of head injury on cognition would result in diminished neuropsychological test performance relative to individuals with a similar head injury history but who did not have their attention called to their head injury history ('diagnosis threat'). Of 36 participants with a history of mild head injury, 17 were randomly assigned to diagnosis threat and 19 to neutral test directions. The diagnosis threat group performed significantly worse on tests measuring general intellect and memory, but were not different from the neutral group in basic attention or psychomotor speed. The diagnosis threat group rated themselves as putting forth less effort on the neuropsychological battery, and self-rated effort correlated with test performance in that group. Overall, results serve as a reminder that neuropsychological tests are measures of behavior, and thus can be influenced by nonneurological factors.

Adolescent↗
PubMed2002

Postconcussive symptom report: the relative influence of head injury and depression.

The present study explored whether any subset of self-reported postconcussion (PCS) symptoms or specific PCS symptom is sensitive and/or specific to head injury in non-self-selected samples of individuals aged 18-21 with head injury and depression (n = 32), head injury without depression (n = 31), depression without head injury (n = 25), and controls (n = 50). All participants completed a self-report PCS symptom scale based on their current symptoms. Results showed that depression, not head-injury status, largely accounted for elevation in PCS symptom reports, including cognitive symptoms. Thus, report of cognitive PCS symptoms is not specific to head injury, raising concerns about using such items to screen for head injury in the general population.

Adolescent↗
PubMed2002

Perception of illness: nonspecificity of postconcussion syndrome symptom expectation.

A growing number of studies show postconcussion syndrome (PCS) symptom report is influenced by factors other than head injury, suggesting symptoms typically associated with PCS may not be specific to head injury. Given the role that symptom expectation has been hypothesized to play in PCS symptom etiology, a comparison of symptoms expected for various disorders seems overdue. The present study asked 82 undergraduates to report the symptoms they currently experience, and then to report the symptoms they would expect to experience if they had had suffered either a head injury, an orthopedic injury, posttraumatic stress, or depression. No current differences in overall symptoms or in symptom subscales emerged. Results showed individuals portraying head injury, posttraumatic stress, and depression expected an increase in total symptoms, though individuals portraying an orthopedic injury did not expect such an increase. Results also showed simulators of head injury, posttraumatic stress, and depression expected equivalent rates of overall symptoms, memory/cognitive complaints, somatic concerns, and distracter symptoms, though head-injured individuals reported fewer affective symptoms than those portraying psychological disorders. In all, these findings suggest that individuals have a relative lack of specificity in symptom expectation for various disorders, with the implication that symptom checklists for "PCS" may not be useful for diagnosis.

Accidents, Traffic↗
PubMedDate not supplied

Axis I comorbidity in body dysmorphic disorder.

Although research on body dysmorphic disorder (BDD) has increased in recent years, this disorder's comorbidity has received little empirical attention. Further work in this area is needed, as it appears that most patients with BDD have at least one comorbid disorder. This study examined axis I comorbidity and clinical correlates of comorbidity in 293 patients with DSM-IV BDD, 175 of whom participated in a phenomenology study and 118 of whom participated in treatment studies of BDD. Subjects were evaluated with the Structured Clinical Interview for DSM-III-R (SCID-P) and a semistructured instrument to obtain information on clinical correlates. Comorbidity was common, with a mean of more than two lifetime comorbid axis I disorders in both the phenomenology and treatment groups. In both groups, the most common lifetime comorbid axis I disorders were major depression, social phobia, obsessive compulsive disorder (OCD), and substance use disorders. Social phobia usually began before onset of BDD, whereas depression and substance use disorders typically developed after onset of BDD. A greater number of comorbid disorders was associated with greater functional impairment and morbidity in a number of domains. Thus, axis I comorbidity is common in BDD patients and associated with significant functional impairment.

Adult↗