Biomedical subjects

Michael David Horner

Publications and source records attributed to Michael David Horner.

9 recordsLinked to original sources

PubMed2006

Convergent and divergent validity of the Gordon Diagnostic System in adults.

The present study examined the convergent and divergent validity of the Gordon Diagnostic System (GDS) as a measure of attention in adults by examining correlations between GDS scores and scores on other attentional and non-attentional measures in 77 veterans (4 women and 73 men) referred for neuropsychological evaluation. Scores on the GDS were neither significantly correlated with scores on other attentional nor non-attentional measures. Participants were then divided into two groups, those who scored lower (<1S.D. below the published normative mean) and higher on the GDS for the Vigilance and Distractibility tasks separately. Participants with lower GDS scores on the Vigilance task performed more poorly on the Trailmaking Test, Part B than those with higher GDS scores. There were no other group differences on tests of attentional or non-attentional functions. These results do not provide strong support for the convergent and divergent validity of the GDS as a measure of attention in adults.

Adult↗

PubMed2006

Abbreviated form of the test of memory malingering.

The Test of Memory Malingering (TOMM) is a neuropsychological effort test in which scores below 45 on Trial 2 or Retention Trial indicate insufficient effort on testing, but Trial 1 score is not used. This study attempted to identify Trial 1 cut points above and below which further trials need not be administered. Data were analyzed from 114 patients referred for clinical neuropsychological evaluation. Sensitivity, specificity, and positive and negative predictive value for identifying failure on TOMM were calculated. Trial 1 scores > or =36 indicated 99% likelihood that TOMM would be passed; Trial 1 scores < or =27 indicated 100% likelihood of failure.

Adult↗

PubMed2005

Patterns of alcohol use 1 year after traumatic brain injury: a population-based, epidemiological study.

This study delineated patterns of alcohol use 1 year after traumatic brain injury (TBI) in a large, population-based, epidemiological, nonclinical sample, and identified predictors of heavy alcohol use in these individuals. Participants were 1,606 adults identified by review of a South Carolina statewide hospital discharge data set, on the basis of satisfying the Centers for Disease Control case definition of TBI, and were interviewed by telephone 1 year after TBI-related discharge. Alcohol use in the month prior to interview was classified according to categories from the Quantity-Frequency-Variability Index; heavy drinking was defined as nearly daily use with > or = 5 drinks at least occasionally, or at least three occasions with > or = 5 drinks. A polychotomous logistic regression with 3 response levels (heavy, moderate, and abstinent/infrequent/light drinking) was used to identify predictors of heavy drinking. Heavy drinking in the month prior to interview was reported by 15.4% of participants, while 14.3% reported moderate drinking and 70.3% reported abstinence or light/infrequent drinking. Risk factors for heavy drinking included male gender, younger age, history of substance abuse prior to TBI, diagnosis of depression since TBI, fair/moderate mental health, and better physical functioning. There was no association between drinking patterns and TBI severity.

Adolescent↗

PubMed2005

Functional neuroanatomy of subcomponent cognitive processes involved in verbal working memory.

Recent research has used functional magnetic resonance imaging (fMRI) to examine brain regions related to specific subcomponent cognitive processes of verbal working memory, which include initial encoding of material, maintenance of the information over a brief delay interval, and later retrieval of the information. The present study examined each of these subcomponents in 14 healthy adults using a Sternberg verbal working memory task and fMRI. Group analysis revealed several brain regions active during all subcomponent processes, which included dorsolateral and ventrolateral prefrontal, parietal, hippocampal, and premotor cortex. Several other brain regions showed activation limited to specific subcomponent processes.

Adult↗

PubMed2004

A pilot study of functional magnetic resonance imaging brain correlates of deception in healthy young men.

We hypothesized that specific brain regions would activate during deception, and these areas would correlate with changes in electrodermal activity (EDA). Eight men were asked to find money hidden under various objects. While functional MRI images were acquired and EDA was recorded, the subjects gave both truthful and deceptive answers regarding the money's location. The group analysis revealed significant activation during deception in the orbitofrontal cortex (OFCx) and anterior cingulate (AC), but individual results were not consistent. Individually and as a group, EDA correlated with blood flow changes in the OFCx and AC. Specific brain regions were activated during deception, but the present technique lacks good predictive power for individuals.

Adolescent↗

PubMed2002

Neurocognitive functioning in posttraumatic stress disorder.

This paper reviews the literature on performance on standard neuropsychological tests among individuals with posttraumatic stress disorder (PTSD). Of 19 studies, 16 reported impairment of attention or immediate memory (or both); however, most of these studies included PTSD patients with significant psychiatric comorbidity, so that the extent to which the observed deficits are specifically attributable to PTSD remains unclear. Other potential confounds, including medical illness, substance abuse, and motivational factors, further preclude definitive conclusions at present. Results of structural and functional neuroimaging studies of PTSD are also summarized. Two studies have reported correlations between hippocampal volume and cognitive findings in PTSD patients; functional studies have indicated specific findings in limbic regions, although the relationship of these results to neuropsychological performance remains to be explored.

Brain↗

PubMed2002

The trail making test, part B: cognitive flexibility or ability to maintain set?

The Trail Making Test (TMT) is a well-established test sensitive to impairment in multiple cognitive domains. There has been ambiguity about which cognitive demands are placed on the patient by TMT Part B over and above those required to perform TMT Part A. In particular, cognitive flexibility and ability to maintain a complex response set have been 2 competing hypotheses. This study preliminarily examined which of these 2 abilities primarily contributes to Part B performance. A total of 121 clinically referred Veterans Affairs patients were administered the TMT, as well as other tests of executive and other cognitive functions. Regression analyses were used to examine which tests predicted Part B performance above and beyond Part A performance. The results provide preliminary support for TMT Part B performance being more sensitive to cognitiveflexibility (operationalized as Wisconsin Card Sorting Test [WCST], percent perseverative errors) than ability to maintain set (operationalized as WCST, failure to maintain set).

Adult↗

PubMed2002

Construct validity of the Babcock Story Recall Test.

The construct validity of the Babcock Story Recall Test (BSRT), a verbal memory measure, was examined by correlating its scores with scores on other neuropsychological tests in 71 substance abuse outpatients. Scores on the BSRT were strongly correlated with the Wechsler Memory Scale-Revised Logical Memory scores, although they were also correlated with some nonmemory indexes. The results provide some support for the construct validity of the BSRT as a measure of memory for structured verbal information.

Cognition Disorders↗

PubMedDate not supplied

Relationship of the Wender Utah Rating Scale to objective measures of attention.

The Wender Utah Rating Scale (WURS) is a 25-item self-report questionnaire for the retrospective assessment of childhood attention-deficit hyperactivity disorder (ADHD) symptoms; high scores indicate greater symptoms. The current study used 35 male Veterans Affairs outpatients to determine if WURS scores were associated with objective measures of current attentional functioning, including the Trail Making Test, Gordon Diagnostic System, Wechsler Adult Intelligence Scale-Revised digit span and digit symbol subtests, and Wechsler Memory Scale-Revised mental control subtest. Participants included both adults diagnosed with ADHD (n = 14) and non-ADHD adults (n = 21). After Bonferroni correction, Pearson product moment correlation coefficients revealed that greater symptoms on the WURS were associated with poorer digit symbol performance (r = -0.69, P < .05). To determine which indices best predicted WURS scores, scores on attention tests and demographic variables were entered into a stepwise multiple regression analysis. Digit symbol performance was the only significant predictor of WURS scores (R(2) = 0.59, P < .01). Thus, poor performance on a sensitive, but nonspecific, measure of attention with executive function, response speed, and visuomotor coordination components was related to greater self-report of childhood ADHD symptoms.

Adult↗