Lauren L. Drag

Contemporary Review 2009: Cognitive Aging

This article addresses key topics in cognitive aging, intending to provide the reader with a brief overview of the current state of research in this growing, multidisciplinary field. A summary of the physiological changes in the aging brain is provided as well as a review of variables that influence cognitive abilities in older age. Normal aging differentially affects various aspects of cognition, and specific changes within various domains such as attention, executive functioning, and memory are discussed. Various theories have been proposed to account for the cognitive changes that accompany normal aging, and a brief examination of these theories is presented in the context of these domain-specific changes.

Self-reported cognitive symptoms following mild traumatic brain injury are poorly associated with neuropsychological performance in OIF/OEF veterans

Mild traumatic brain injury (mTBI) is not uncommon among Operation Iraqi Freedom/Operation Enduring Freedom (OIF/OEF) veterans, and many individuals within this group report lingering cognitive difficulties following their injury. For Department of Veterans Affairs clinicians, an accurate assessment of cognitive symptoms is important in providing appropriate clinical care. Although self-assessment is commonly employed to screen for difficulties in cognitive functioning, little is known about the accuracy of self-report in this population. This study collected cognitive, psychiatric, and self-report data from 105 OIF/OEF veterans with mTBI to examine the relationship between self-reported cognitive functioning and objective neuropsychological test performance. Additionally, clinicians who frequently work with OIF/OEF veterans were asked to predict the magnitude of these associations. Self-reported cognitive functioning was not significantly correlated with objective cognitive abilities, suggesting that objective neuropsychological testing should be used when cognitive weakness is suspected. Perceived cognitive deficits were associated with depression, anxiety, and posttraumatic stress disorder, illustrating the additional importance of adequate assessment and treatment of psychiatric symptoms. Clinicians tended to overestimate the association between self-report and test performance.

The contributions of self-reported injury characteristics and psychiatric symptoms to cognitive functioning in OEF/OIF veterans with mild traumatic brain injury.

Mild traumatic brain injury (mTBI) affects a significant number of combat veterans returning from Operation Enduring Freedom/Operation Iraqi Freedom (OEF/OIF). Although resolution of mTBI symptoms is expected over time, some individuals continue to report lingering cognitive difficulties. This study examined the contributions of self-reported mTBI injury characteristics (e.g., loss of consciousness, post-traumatic amnesia) and psychiatric symptoms to both subjective and objective cognitive functioning in a sample of 167 OEF/OIF veterans seen in a TBI clinic. Injury characteristics were not associated with performance on neuropsychological tests but were variably related to subjective ratings of cognitive functioning. Psychiatric symptoms were highly prevalent and fully mediated most of the relationships between injury characteristics and cognitive ratings. This indicates that mTBI characteristics such as longer time since injury and loss of consciousness or post-traumatic amnesia can lead to increased perceived cognitive deficits despite having no objective effects on cognitive performance. Psychiatric symptoms were associated with both cognitive ratings and neuropsychological performance, illustrating the important role that psychiatric treatment can potentially play in optimizing functioning. Finally, subjective cognitive ratings were not predictive of neuropsychological performance once psychiatric functioning was statistically controlled, suggesting that neuropsychological assessment provides valuable information that cannot be gleaned from self-report alone.

Cognitive functioning, retirement status, and age: results from the Cognitive Changes and Retirement among Senior Surgeons study.

BACKGROUND Accurate assessment of cognitive functioning is an important step in understanding how to better evaluate both clinical and cognitive competence in practicing surgeons. As part of the Cognitive Changes and Retirement among Senior Surgeons study, we examined the objective cognitive functioning of senior surgeons in relation to retirement status and age. STUDY DESIGN Computerized cognitive tasks measuring visual sustained attention, reaction time, and visual learning and memory were administered to both practicing and retired surgeons at annual meetings of the American College of Surgeons. Data from 168 senior surgeons aged 60 and older were compared with data from 126 younger surgeons aged 45 to 59, with performance below 1.5 standard deviations or more indicating a significant difference between the groups. RESULTS Sixty-one percent of practicing senior surgeons performed within the range of the younger surgeons on all cognitive tasks. Seventy-eight percent of practicing senior surgeons aged 60 to 64 performed within the range of the younger surgeons on all tasks compared with 38% of practicing senior surgeons aged 70 and older. Forty-five percent of retired senior surgeons performed within the range of the younger surgeons on all tasks. No senior surgeon performed below the younger surgeons on all 3 tasks. CONCLUSIONS The majority of practicing senior surgeons performed at or near the level of their younger peers on all cognitive tasks, as did almost half of the retired senior surgeons. This suggests that older age does not inevitably preclude cognitive proficiency. The variability in cognitive performance across age groups and retirement status suggests the need for formal measures of objective cognitive functioning to help surgeons detect changes in cognitive performance and aid in their decisions to retire.

WAIS-IV Reliable Digit Span is no More Accurate Than Age Corrected Scaled Score as an Indicator of Invalid Performance in a Veteran Sample Undergoing Evaluation for mTBI

Reliable Digit Span (RDS) is a measure of effort derived from the Digit Span subtest of the Wechsler intelligence scales. Some authors have suggested that the age-corrected scaled score provides a more accurate measure of effort than RDS. This study examined the relative diagnostic accuracy of the traditional RDS, an extended RDS including the new Sequencing task from the Wechsler Adult Intelligence Scale-IV, and the age-corrected scaled score, relative to performance validity as determined by the Test of Memory Malingering. Data were collected from 138 Veterans seen in a traumatic brain injury clinic. The traditional RDS (⩽ 7), revised RDS (⩽ 11), and Digit Span age-corrected scaled score (⩽ 6) had respective sensitivities of 39%, 39%, and 33%, and respective specificities of 82%, 89%, and 91%. Of these indices, revised RDS and the Digit Span age-corrected scaled score provide the most accurate measure of performance validity among the three measures.

Source memory and frontal functioning in Parkinson’s disease

The most extensively described pathological abnormality in Parkinsons disease (PD) is loss of dopaminergic neurons in the substantia nigra pars compacta and the ventral tegmental area, with degeneration of their striatal terminals. Because of the intimate connections between the striatum and the frontal lobes, individuals with PD often demonstrate impairments on those tasks relying on the prefrontal cortex (e.g., tests of executive functioning). Source memory, or memory for context, is believed to rely on the prefrontal cortex and has been previously associated with executive functioning performance, although it has received little attention in the PD literature. Executive functioning and source memory were measured in a group of nondemented PD patients and healthy control participants. Within the PD group, an anti-Parkinsons medication withdrawal manipulation was used to examine whether source memory was affected by phasic changes in dopamine levels. Compared to healthy control participants, PD patients were impaired in source memory (both on- and off-medication) and on a composite measure of executive functioning. Within the PD group, medication administration improved motor performance but did not have a significant effect on source memory.

Predictors of inpatient and outpatient healthcare utilization in veterans with traumatic brain injury.

Objective:Traumatic brain injury (TBI) can place a significant financial and resource burden on healthcare systems. This study examined predictors of outpatient and inpatient healthcare utilization in veterans with a history of TBI. Methods:A secondary analysis was conducted on data from 1565 veterans with TBI and 1565 veterans without TBI seen for healthcare services at the VA Palo Alto Health Care System between 2000 and 2010. Patterns and predictors of outpatient and inpatient medical and psychiatric care were examined. Results:Veterans with TBI utilized significantly more services compared with the control group. The TBI group was seen for more than 160 000 outpatient services and was almost 9 times more likely to be hospitalized than the control group. Although psychiatric disorders were more prevalent in the TBI group and associated with increased medical and mental health utilization within the TBI group, they did not account fully for the significant group differences. Conclusions:Veterans with a history of TBI have much greater healthcare needs than veterans without TBI, likely because of non–TBI-related factors. Increased monitoring and early intervention treatments may be warranted for certain at-risk veterans with the goal of minimizing their need for long-term or extensive healthcare services in the future.

Prescribing Practices of Anticholinergic Medications and Their Association With Cognition in an Extended Care Setting

The current study examined prescribing patterns of anticholinergic (AC) medications and their association with cognitive function in 450 nondemented and nondelirious older adults hospitalized in a postacute extended care center. Participants completed a brief neuropsychological battery that included measures of general mental status, memory, judgment, and executive functioning as part of standard clinical care. An AC burden score was calculated for each participant based on medications taken the day of the testing using the Anticholinergic Drug Scale. Although use of AC medications was common, the majority of participants were taking medications with only minimal AC properties. AC burden and total number of AC medications were negatively correlated with age. AC burden was not associated with lower performance on any of the cognitive measures. In sum, current prescribing practices of AC medications are not associated with negative cognitive effects in a sample of older adults hospitalized in an extended care center.

Limited usefulness of the Rey Fifteen-Item Test in detection of invalid performance in veterans suspected of mild traumatic brain injury

Abstract Objective: This study explored using the FIT as a measure of performance validity among veterans undergoing neuropsychological evaluation for mild traumatic brain injury (mTBI). Background: The Rey Fifteen-Item Memory Test (FIT) is a performance validity measure criticized for poor sensitivity. Methods: Two hundred and fifty-seven veterans completed the FIT and Wechsler Adult Intelligence Scale, Fourth Edition, Digit Span (DS); 109 of whom completed the Test of Memory Malingering (TOMM). FIT cut-offs of <9, <8 and stricter cut-offs were examined using DS and/or TOMM as criterion performance validity measures. Results: Only four participants scored below the standard cut score of 9 on the FIT. Among the 13 veterans failing both criterion tests, only two scored below 9 on the FIT. Regardless of which FIT cut-off was used, the FIT had poor diagnostic accuracy. Conclusion: Despite its popularity, the FIT is not supported as an appropriate measure of performance validity in veterans undergoing evaluation for possible mTBI. Therefore, inferences regarding neuropsychological data reliability with adequate statistical certainty require use of other measures of performance validity with greater sensitivity.

Neuropsychological test validity in Veterans presenting with subjective complaints of ‘very severe’ cognitive symptoms following mild traumatic brain injury

Abstract Objective: This study explored the utility of combining data from measures of performance validity and symptom validity among Veterans undergoing neuropsychological evaluation for mild traumatic brain injury (mTBI). Background: Persistent cognitive impairments following mTBI are often reported by returning combat veterans. However, objectively-measured cognitive deficits are not common among individuals with mTBI, raising the question of whether negative impression management influences self-ratings. Methods: Self-report ratings were obtained for memory, concentration, decision-making, and processing speed/organization using a 5-point scale ranging from ‘none’ to ‘very severe’. Veterans also completed brief neuropsychological testing which included measures of performance validity. Results: Study 1 examined data from 122 participants and demonstrated that veterans reporting a ‘very severe’ cognitive deficit were over three times as likely to demonstrate poor effort on a validity test than those without a very severe rating. Study 2 replicated these findings in an independent sample of 127 veterans and also demonstrated that both severity of self-report ratings and performance on an embedded measure of effort were predictive of poor effort on a stand-alone performance validity test. Conclusion: Veterans with suspected mTBI who report ‘very severe’ cognitive impairment have a greater likelihood of putting forth sub-optimal effort on objective testing.