Robert J. McCaffrey

Issues associated with repeated neuropsychological assessments

Distinguishing practice effects from other factors in repeated neuropsychological assessments are discussed in the context of research studies and clinical/forensic assessments. Potential methodological procedures for reducing the impact of practice effects in research settings are outlined. In contrast, the potential clinical utility and interpretation of practice effects in clinical assessments and forensic evaluations are highlighted.

The effect of depression and anxiety on the TOMM in community-dwelling older adults

Tests of possible malingering are in increasing demand among neuropsychologists. The Test of Memory Malingering (TOMM) is resistant to many neurological conditions, including traumatic brain injury, dementia, and aphasia. Less clear is the impact of psychological conditions on TOMM performance. This study examined a sample of community-based older adults (55-75) to determine whether scores on the TOMM are influenced by the presence of symptoms of depression or anxiety, as measured by the Beck Depression Inventory (BDI) and State-Trait Anxiety Inventory (STAI), respectively. The results indicate that, regardless of BDI or STAI scores, all subjects scored above 45 correct out of 50 on TOMM Trial 2. These findings demonstrate that depression and anxiety levels in an older community-dwelling sample do not negatively affect performance on the TOMM.

Multiple Chemical Sensitivity: A Review of the Theoretical and Research Literature

Multiple chemical sensitivity (MCS) is a term used to describe a disorder characterized by a vast array of somatic, cognitive, and affective symptoms, the cause of which is attributed to exposure to extremely low levels of a variety of chemicals. Upon examination of the patient with a diagnosis of MCS, objective physical findings and consistent laboratory abnormalities are typically nonexistent. The concept of MCS has ignited considerable controversy in the fields of toxicology, immunology, allergy, psychology, and neuropsychology. Central to the controversy is the disagreement over the extent to which the manifestation of MCS is mediated by psychological factors. Because of the large number of neuropsychological symptoms associated with a diagnosis of MCS, neuropsychologists are increasingly receiving referrals for the assessment of these patients. It is important, therefore, that neuropsychologists become aware of the variety of clinical issues that must be taken into account when assessing an individual with a diagnosis of MCS. The theoretical and research literature on individuals with a diagnosis of MCS is reviewed here.

Polychlorinated biphenyl exposure and neuropsychological status among older residents of upper Hudson River communities.

Background Polychlorinated biphenyls (PCBs) may accelerate the cognitive and motor dysfunction found in normal aging, but few studies have examined these outcomes and PCB exposure among older adults. Objective We evaluated neuropsychological status and low-level PCB exposure among older adults living along contaminated portions of the upper Hudson River in New York. Methods A total of 253 persons between 55 and 74 years of age were recruited and interviewed, and provided blood samples for congener-specific PCB analysis. Participants also underwent a neuropsychological battery consisting of 34 tests capable of detecting subtle deficits in cognition, motor function, affective state, and olfactory function. Results After adjustment for potential confounders, the results indicated that an increase in serum total PCB concentration from 250 to 500 ppb (lipid basis) was associated with a 6.2% decrease in verbal learning, as measured by California Verbal Learning Test trial 1 score (p = 0.035), and with a 19.2% increase in depressive symptoms, as measured by the Beck Depression Inventory (p = 0.007). Conclusions The results suggest that exposure to PCBs may be associated with some measures of memory and learning and depression among adults 55–74 years of age whose current body burdens are similar to those of the general population. Although the results are useful in delineating the neuropsychological effects of low-level exposure to PCBs, further studies of whether older men and women are a sensitive subpopulation are needed.

Electrical injury and lightning injury: a review of their mechanisms and neuropsychological, psychiatric, and neurological sequelae

Exposure to electrical current via industrial or residential accidents or lightning strikes is a serious and growing concern in todays medical community. The sequelae that result are referred to as electrical injury (EI) or lightning injury (LI). The relevant principles in electricity are reviewed with particular attention given to their damaging capabilities on the body. Specific neuropsychological, psychiatric, and neurological signs and symptoms as well as objective measures of psychological and neuropsychological functioning and brain imaging in victims of EI and LI, are reviewed from past research. Important issues relevant to researchers in the field are discussed. Finally, the role that neuropsychology might play in this area is outlined.

Using the TOMM for evaluating children's effort to perform optimally on neuropsychological measures.

Suboptimal effort is a threat to the validity of neuropsychological evaluations. Numerous papers have been devoted to this subject and a large number of measures have been developed in an attempt to detect suboptimal effort. To date, however, the clinical literature has focused almost exclusively on identifying suboptimal effort in adults, whereas suboptimal effort among children has not been addressed thoroughly in the clinical neuropsychological literature. The present study investigated whether or not already established effort measures could be used with children. The Test of Memory Malingering (TOMM) and the Rey-15-item test were administered to 128 children in two sites, the USA and Cyprus. The results indicated that the TOMM has the potential to be used as a measure for identifying children who do not put forth maximal effort during neuropsychological evaluations. In contrast, the Rey-15-item test does not appear to be a promising measure of effort for use with children, especially younger children.

Estimating the half-lives of PCB congeners in former capacitor workers measured over a 28-year interval

To date, most estimates of the half-life of polychlorinated biphenyls (PCBs) in humans have been based on relatively short follow-up periods. To address this issue, we determined the half-lives of PCB congeners of occupational origin in the serum of former capacitor workers as part of a study conducted in 2003–2006 — approximately 28 years after their last occupational exposure. A total of 241 persons from a source population of 6798 former capacitor workers were interviewed and asked to donate a blood sample for serum PCB congener analysis. A subgroup of 45 participants also had serum archived from 1976 and reanalyzed for the same 27 PCB congeners by the same laboratory. Our estimates of the half-lives of the congeners among these 45 persons were longer than those reported by Wolff et al. (1992), due primarily to the much longer interval between exposure and determination of serum PCB concentrations. Half-lives were significantly greater for the heavy versus light occupational congeners, for women versus men and for those with low versus high initial exposure. Current serum total PCB concentrations, expressed as the geometric mean of wet weight data, averaged 6.7 ng/g for the entire 241-person cohort, which represents a 10-fold decrease from values reported in the late 1970s, but is still nearly twice the average for persons of similar age residing in the same area, but without occupational exposure. In addition, current serum PCB concentrations remained significantly and positively associated with earlier occupational exposure, but were not associated with fresh water fish consumption. In general, the results support a consistent and long-duration trend of increased PCB body burden in this cohort of former capacitor workers compared with non-occupationally exposed individuals. The results may aid in further understanding the toxicological/epidemiological consequences of exposure to PCBs in humans.

Examining the Test of Memory Malingering Trial 1 and Word Memory Test Immediate Recognition as Screening Tools for Insufficient Effort

Assessing effort level during neuropsychological evaluations is critical to support the accuracy of cognitive test scores. Many instruments are designed to measure effort, yet they are not routinely administered in neuropsychological assessments. The Test of Memory Malingering (TOMM) and the Word Memory Test (WMT) are commonly administered symptom validity tests with sound psychometric properties. This study examines the use of the TOMM Trial 1 and the WMT Immediate Recognition (IR) trial scores as brief screening tools for insufficient effort through an archival analysis of a combined sample of mild head-injury litigants ( N = 105) who were assessed in forensic private practices. Results show that both demonstrate impressive diagnostic accuracy and calculations of positive and negative predictive power are presented for a range of base rates. These results support the utility of Trial 1 of the TOMM and the WMT IR trial as screening methods for the assessment of insufficient effort in neuropsychological assessments.

Practice Effects Predict Cognitive Outcome in Amnestic Mild Cognitive Impairment

OBJECTIVE Practice effects on cognitive tests have been shown to further characterize patients with amnestic mild cognitive impairment (aMCI) and may provide predictive information about cognitive change across time. We tested the hypothesis that a loss of practice effects would portend a worse prognosis in aMCI. DESIGN Longitudinal, observational design following participants across 1 year. SETTING Community-based cohort. PARTICIPANTS Three groups of older adults: 1) cognitively intact (n = 57), 2) aMCI with large practice effects across 1 week (MCI + PE, n = 25), and 3) aMCI with minimal practice effects across 1 week (MCI - PE, n = 26). MEASUREMENTS Neuropsychological tests. RESULTS After controlling for age and baseline cognitive differences, the MCI - PE group performed significantly worse than the other groups after 1 year on measures of immediate memory, delayed memory, language, and overall cognition. CONCLUSIONS Although these results need to be replicated in larger samples, the loss of short-term practice effects portends a worse prognosis in patients with aMCI.

Appropriateness of kaolin consumption as an index of motion sickness in the rat

The appropriateness of kaolin consumption, one form of pica, as an index of motion sickness in the rat was examined. Unlike other motion sickness indices, the use of kaolin consumption results in a bitonic function across daily rotation sessions. This bitonic function is not predicted from any theory of motion sickness (viz., the Sensory Rearrangement Theory), rather an inverse relationship should exist between the severity of motion sickness and repeated exposure to the effective motion (i.e., habituation). The results of Experiments 1 and 2 support the continued use of kaolin consumption as an index of motion sickness in the rat. A response interference process is proposed to account for the first portion of the bitonic kaolin consumption function with grooming possibly representing a higher probability behavior than kaolin consumption. Experiment 3 examined and confirmed that kaolin consumption indexes the process of rehabituation to an effective motion. This extends the number of principles that are characteristic of motion sickness exhibited by species capable of emesis and supports the continued use of kaolin consumption as an index of motion sickness and general gastrointestinal malaise in the rat.