In his text, Behavioral Neurology of White Matter, Filley focuses our attention on the role of white matter in neurobehavioral functioning. He makes the point that much of clinical neuroscience, including neuropsychology and behavioral neurology, has focused on cognitive correlates of cortical lesions and disorders. Historically in neuropsychology, we have acknowledged the role of white matter more typically in vague terms of connecting pathways, but there has been a decided emphasis on cortical and subcortical gray matter regions as “where the action is.” Filley's insightful writing clearly supports his proposal that “the mind depends as much on the white matter as on its gray counterpart.

Neuropsychological studies of temporal lobe epilepsy have focused heavily on the nature and extent of memory dysfunction and its relationship to the neuropathological status of the hippocampus and related mesial temporal lobe structures. In this study, we examined whole brain and lobar quantitative MRI volumes and comprehensive neuropsychological performance in 58 patients with temporal lobe epilepsy and 62 healthy controls in order to determine (1) the nature and degree of extratemporal structural abnormalities in localization-related temporal lobe epilepsy; (2) the nature and degree of cognitive abnormalities outside of anterograde memory function; and (3) the relationship of volumetric abnormalities to neuropsychological status. Temporal lobe epilepsy patients exhibited significant reduction in the volume of adjusted (age, gender, height) total cerebral tissue (−5.8%), more evident in white (−9.8%) compared to gray matter (−3.0%) tissue volumes. Significant volumetric reductions were evident across frontal, temporal and parietal but not occipital lobe regions. Subarachnoid but not total ventricular CSF was significantly increased in epilepsy patients. Neuropsychological abnormality was generalized in nature, consistent with the generalized nature of the morphometric abnormalities, and reductions in cerebral tissue volumes were directly associated with poorer cognitive performance. In summary, patients with temporal lobe epilepsy exhibited clinically significant structural and functional abnormalities that extended outside the epileptogenic temporal lobe. The degree to which these structural and cognitive abnormalities are due to factors that cause the epilepsy, as opposed to reflecting the consequences of chronic epilepsy (e.g., duration and severity of epilepsy), remain to be determined. (JINS, 2003, 9, 353–362.)

Many recent findings in Western countries suggest that episodic recall is the most sensitive discriminator between patients with mild Alzheimer disease (AD) and the normal elderly, while semantic memory tends best to differentiate between moderate and severe AD patients. The present study is the first to examine in detail the episodic memory of Chinese AD patients in Hong Kong with a locally developed list learning test, comparing procedures that do or do not encourage the use of semantic organization. The performance of 28 AD patients was compared to that of 30 normal controls. AD patients did significantly worse in terms of acquisition and retention and also benefited significantly less from external organization cues. In the discriminant function analysis, the rate of forgetting in the random condition and the total retention score in the blocked condition were found to be the best predictors for differentiating between AD patients and controls. On the other hand, in the differentiation between mild and moderate AD, semantic clustering in the blocked condition was found to be the best predictor. Results of the present study were discussed in the light of the previous findings reported in the Western countries and the neuropathological changes of AD patients. (JINS, 2003, 9, 363–375.)

The purpose of this study was to investigate and extend previously reported sex differences in object location memory by comparing the performance of heterosexual and homosexual males and females. Subjects were 240 healthy, right-handed heterosexual and homosexual males and females. They were instructed to study 16 common, gender-neutral objects arranged randomly in an array and subsequently tested for object recall, object recognition and spatial location memory. Females recalled significantly more objects than males, although there were no group differences in object recognition. Decomposition of significant interactions between sex and sexual orientation on spatial location memory (controlling for differences in object recall, age and IQ) revealed that heterosexual females and homosexual males scored better than heterosexual males, and no different from each other. There were no differences between homosexual and heterosexual females. The findings suggest that homosexual males and heterosexual females encode, store and retrieve positional and relational information about spatial layouts similarly, pointing to within-sex variations in the neural architecture underlying spatial memory. (JINS, 2003, 9, 376–383.)

Animal word list generation (ANWLG) was administered to 47 first-episode schizophrenia (FES) participants and 31 controls. Fifty-nine left temporal lobe epilepsy (LTLE) participants were included as a comparison group with known temporal lobe damage and expected semantic deficits. Semantic knowledge was assessed with the Association Index (AI), a measure of the semantic relatedness of all consecutive ANWLG responses. Neuropsychological tests of language and executive functioning were also administered. Results showed that both FES and LTLE groups generated fewer ANWLG responses than controls, but only the LTLE participants obtained a lower AI relative to controls. FES participants did not differ from controls on the AI. FES and LTLE groups produced fewer semantic subcategories (clusters), however, only the LTLE group produced fewer words per subcategory compared to controls (cluster size). FES participants produced a higher rate of perseverative responses compared to the other groups. Finally, correlation analyses showed that for FES participants both executive and language tests significantly correlated with ANWLG total responses, while the correlation between ANWLG and only 1 language test was significant for LTLE participants. Taken together, the results suggest that reduced ANWLG output in FES participants may be best conceptualized as a deficit in the executive component of word list generation (i.e., semantic search/access, response monitoring) or global cognitive impairment. (JINS, 2003, 9, 384–393.)

Previous research has demonstrated dissociations between categorization and recognition performance in amnesic patients, supporting the idea that separate memory systems govern these tasks. However, previous research has also demonstrated that these dissociations are predicted by a single-system model that allows for reasonable parameter differences across groups. Generally, previous studies have employed categorization tasks that are less demanding than the recognition tasks. In this study, we distinguish between single-system and multiple-system accounts by testing memory-impaired individuals in a more demanding categorization task. These patients, just like previous amnesic participants, show a dissociation between categorization and recognition when tested in previously employed paradigms. However, they display a categorization deficit when tested in the more challenging categorization task. The results are interpreted as support for a single-system framework in which categorization and recognition depend on one representational system. (JINS, 2003, 9, 394–406.)

To explore possible neurotoxic sequelae of Gulf War (GW) participation, olfactory identification performance, neurocognitive functioning, health perceptions, and emotional distress were assessed in 72 veterans deployed to the GW and 33 military personnel activated during the GW but not deployed to the war zone. Findings revealed that war-zone-exposed veterans reported more concerns about health, cognitive functioning, and depression than did their counterparts who did not see war-zone duty. There was no evidence that performances on olfactory or neurocognitive measures were related to war-zone duty or to self-reported exposure to GW toxicants. However, symptoms of emotional distress were positively correlated with self-report of health and cognitive complaints. Results do not provide support for the hypothesis that objectively-measured sensory (i.e., olfactory) or cognitive deficits are related to war-zone participation but do underscore the increasingly demonstrated association between self-reported health concerns and symptoms of emotional distress. (JINS, 2003, 9, 407–418.)

Performance on many cognitive and neuropsychological tests may be improved by prior exposure to testing stimuli and procedures. These beneficial practice effects can have a significant impact on test performance when conventional neuropsychological tests are administered at test–retest intervals of weeks, months or years. Many recent investigations have sought to determine changes in cognitive function over periods of minutes or hours (e.g., before and after anesthesia) using computerized tests. However, the effects of practice at such brief test–retest intervals has not been reported. The current study sought to determine the magnitude of practice effects in a group of 113 individuals assessed with an automated cognitive test battery on 4 occasions in 1 day. Practice effects were evident both between and within assessments, and also within individual tests. However, these effects occurred mostly between the 1st and 2nd administration of the test battery, with smaller, nonsignificant improvements observed between the 2nd, 3rd, and 4th administrations. On the basis of these results, methodological and statistical strategies that may aid in the differentiation of practice effects from drug-induced cognitive changes are proposed. (JINS, 2003, 9, 419–428.)

Previous studies of depression after stroke have reported widely variable findings, possibly due to differences between studies in patient characteristics and methods for the assessment of depression, small sample sizes, and the failure to examine stroke-free reference groups to determine the base rate of depression in the general population. In an effort to address certain of those methodologic issues and further investigate the frequency and clinical determinants of depression after stroke, we administered the Structured Interview Guide for the Hamilton Depression Rating Scale (SIGH–D) and neurological, neuropsychological, and functional assessments to 421 patients (age = 71.5 ± 8.0 years) 3 months after ischemic stroke and 249 stroke-free control subjects (age = 70.8 ± 6.7 years). We required a SIGH–D total score > 11 for the identification of depression. We found that depression was less frequent (47/421 patients, or 11.2%, and 13/249 control subjects, or 5.2%), less severe, and less persistent in our stroke cohort than previously reported, possibly due to the underrepresentation of patients with a premorbid history of affective illness. Depression was associated with more severe stroke, particularly in vascular territories that supply limbic structures; dementia; and female sex. SIGH–D item analyses suggested that a reliance on nonsomatic rather than somatic symptoms would result in the most accurate diagnoses of depression after ischemic stroke. (JINS, 2003, 9, 429–439.)

Among children born at extremely low birthweight (ELBW: <1000 g at birth) there is an association between the presence of periventricular brain injury (PVBI) and lowered performance on tests of reading and spelling ability. The present study was designed to determine if this association might be related to underlying dysfunction in the subcortical magnocellular visual pathway or its cortical targets in the dorsal stream, a prediction motivated by the magnocellular theory of dyslexia. Thirty-five ELBW children were divided into two groups based upon the presence or absence of PVBI (no PVBI, n = 11; PVBI, n = 24). The performance of these two groups was compared to that of a group of healthy full term children (n = 12) on a motion-defined form recognition task believed to tap into the functioning of the magnocellular pathway and/or the dorsal stream. ELBW children did, in fact, show a striking impairment on this task, with 71% of the sample performing at a level more than three standard deviations below the mean of full term controls. Surprisingly, their difficulties were not found to be related to either the presence of brain injury (verified by neonatal cranial ultrasound) or to problems with reading or spelling. An association was documented, however, between difficulties with motion processing and performance on several subtests of the Performance IQ scale of the Wechsler Intelligence Scale for Children–Third Edition. This latter finding is consistent with our earlier suggestion that magnocellular pathway/dorsal stream dysfunction may underlie problems with visuospatial and visuomotor performance in this population. (JINS, 2003, 9, 440–449.)

Poor awareness of deficit is common after brain injury. Recent literature has examined various tools for measurement of this phenomenon; the most widely used being self–other rating scales. Although self–other scale measures have face validity, their criterion-related validity has not been adequately demonstrated, and there is little information as to whether and how they relate to other neuropsychological measures. The present study compared measurement of awareness by the Dysexecutive (DEX) Questionnaire self–other rating scale with the Self-Awareness of Deficits Interview (SADI), a semistructured interview measure. Evaluation of awareness by these measures was compared to tests of executive functioning and IQ. Results indicated significant, albeit marginal relationships between the two measures, and better correlation of the SADI with measures of frontal lobe functioning. The SADI also predicted injury severity. (JINS, 2003, 9, 450–458.)

The very high sensitivity and specificity of odor identification tasks in discriminating between Alzheimer's patients and normals suggests that they reflect the presence of underlying neuropathology. Significant neuropathological changes are seen in areas critical to processing olfactory information, even in the early stages of Alzheimer's disease (AD). The current study was designed to investigate whether performance on olfactory tasks (odor threshold and odor identification) was related to volumetric MRI measures of mesial temporal areas central to olfactory information processing and important in the neuropathology of AD. Participants were 8 male and 5 female patients with probable AD, and 10 male and 12 female normal age-matched controls, diagnosed at the UCSD Alzheimer's Disease Research Center. The study investigated correlations between volumetric measures of hippocampus, the parahippocampal gyrus and the amygdala, and the psychophysical measures of olfactory function. Robust relationships were observed between mesial temporal lobe volumes and olfactory functional measures. The finding of a strong relationship between left hippocampal volume and performance on the odor identification task (r = .85) is compatible with a left-hemisphere superiority for verbally mediated olfactory tasks. The findings suggest a neural substrate for the breakdown in functional performance on verbally mediated odor identification tasks in Alzheimer's disease and suggest the utility of quantitative MRI measures and psychophysical performance in the assessment of AD. These results support the potential clinical utility of inclusion of odor identification tests in diagnostic batteries for detecting AD. (JINS, 2003, 9, 459–471.)

Within the last decade, various applications of two-way audio-visual telecommunication have been implemented in the Norwegian health care system to facilitate the delivery of medical services to patients located in rural areas away from the hospitals. This technology may also be useful to extend neuropsychological services to underserved areas and thereby reduce the patients' travel time and costs. In the current study, a total of 12 visual, verbal and performance tests were administered face-to-face and via videophones to 32 volunteer participants to examine the consistency and stability of test-scores when delivered via different formats. The obtained reliability coefficients ranged from .37 to .86 with a median value of .74. When testing for mean differences, the measures on verbal learning (WMS–Logical Memory I) and auditory attention (Seashore Rhythm Test) differed significantly due to administration format (t = 2.34, p = .024 and t = 2.37, p = .025, respectively). The findings imply that administration format does not appear to affect the reliability of measurement but neuropsychological test performance is significantly higher for the measures of attention and memory when delivered via videophone. Additional research on these cognitive domains is required, and if the observed differences due to testing format persist, separate normative data via telecommunication will be required before assessments are carried out. Also, since only normal participants were included in this study, the findings may have external validity for normal populations, but similar controlled trials with patients need to be completed before remote assessments can be implemented in regular clinical practice. (JINS, 2003, 9, 472–478.)

The following is a correction for an error that occurred in the Journal of the International Neuropsychological Society, Vol. 9, No. 1. The Critical Review titled “Frontal-striatal Circuit Functions: Context, Sequence, and Consequence” by Jean A. Saint-Cyr had two lines of copy accidentally omitted at the bottom of the second column on page 103.

Naming is typically assessed with visual naming tasks, yet, some patients with genuine word-finding difficulty (evident in auditorily based discourse) show minimal difficulty on such measures. Evidence from cortical mapping, brain imaging and neuropsychological studies suggests that auditory naming measures might provide more relevant or at least, complementary information. We developed comparable auditory and visual naming tests and present normative data for accuracy, response time, and tip-of-the-tongue responses based on 100 controls. Test validity was supported by findings that left temporal lobe epilepsy (TLE) patients (i.e., a population with expected naming difficulty) performed more poorly on auditory but not visual naming compared to right TLE patients (i.e., a population without expected naming difficulty). Internal and test–retest reliability coefficients were reasonable. Finally, test utility was assessed on an individual basis, and auditory but not visual naming performance predicted impairment. (JINS, 2003, 9, 479–489.)

Earlier findings in patients with a small supratentorial white matter infarct demonstrated subtle impairments of cognition. This is in line with reported difficulties in regaining premorbid level of functioning in daily life activities, even though any physical neurological deficits are no longer present. Either a “bystander effect” of adjoining gray matter or a long distance effect through hypometabolism or other neurochemical changes might underlie these impairments. To find the best explanation, a group of 17 patients with a lacunar infarct in the brainstem was neuropsychologically evaluated and compared with a closely matched control group. The patients demonstrated significantly impaired task performance on a constellation of neuropsychological tasks that was very similar to the findings previously found in patients with a supratentorial lacunar infarct (Boston Naming Test, TEA visual elevator, category fluency, Trailmaking Test). We conclude that a small white-matter infarct may affect cognitive functioning in a nonspecific way independently of its location. (JINS, 2003, 9, 490–494.)