Longitudinal evaluation of diffusion tensor imaging and cognition in systemic lupus erythematosus

Objective

This pilot study aimed to examine longitudinal changes in brain structure and function in patients with systemic lupus erythematosus (SLE) using diffusion tensor imaging (DTI) and neuropsychological testing.

Methods

Fifteen female SLE patients with no history of major neuropsychiatric (NP) manifestations had brain magnetic resonance imaging (MRI) with DTI at baseline and approximately 1.5 years later. At the same time points, a standardized battery of cognitive tests yielding a global cognitive impairment index (CII) was administered. At baseline, the SLE patients had mean age of 34.0 years (SD = 11.4), mean education of 14.9 years (SD = 2.1), and mean disease duration of 121.5 months (SD = 106.5). The MRI images were acquired with a 3T GE MRI scanner. A DTI sequence with 33 diffusion directions and b-value of 800 s/mm2 was used. Image acquisition time was about 10 minutes.

Results

No significant change in cognitive dysfunction (from the CII) was detected. Clinically evaluated MRI scans remained essentially unchanged, with 62% considered normal at both times, and the remainder showing white matter (WM) hyperintensities that remained stable or resolved. DTI showed decreased fractional anisotropy (FA) and increased mean diffusivity (MD) in bilateral cerebral WM and gray matter (GM) with no major change in NP status, medical symptoms, or medications over time. Lower FA was found in the following regions: left and right cerebral WM, and in GM areas including the parahippocampal gyrus, thalamus, precentral gyrus, postcentral gyrus, angular gyrus, parietal lobe, and cerebellum. Greater MD was found in the following regions: left and right cerebral WM, frontal cortex, left cerebral cortex, and the putamen.

Conclusions

This is the first longitudinal study of DTI and cognition in SLE, and results disclosed changes in both WM and GM without cognitive decline over an 18-month period. DTI abnormalities in our participants were not associated with emergent NP activity, medical decline, or medication changes, and the microstructural changes developed in the absence of macrostructural abnormalities on standard MRI. Microstructural changes may relate to ongoing inflammation, and the stability of cognitive function may be explained by medical treatment, the variability of NP progression in SLE, or the impact of cognitive reserve.

Site differences in mild cognitive dysfunction (MCD) among patients with systemic lupus erythematosus (SLE)

Background

Mild cognitive dysfunction (MCD) is common in patients with systemic lupus erythematosus (MCD-SLE) but few studies have investigated potential site differences.

Methods

SLE patients from Denver, CO, and New York, NY, were enrolled in two different cognition studies employing similar screening methods. Using the resulting neuropsychological scores, cognitive impairment was calculated using a cognitive impairment index (CII).

Results

The rate of MCD-SLE was 24% at the Denver, CO, site and 60% at the New York, NY, site. The mean CII was 2.6 ± 2.3 versus 4.4 ± 2.7, respectively ( p = 0.005). The NY participants had a significantly longer disease duration ( p = 0.13) and higher American College of Rheumatology SLE criteria scores ( p > 0.001). NY participants had a higher frequency of impairment in semantic verbal fluency ( p = 0.005), visuomotor speed ( p = 0.013), and motor sequencing ( p = 0.001). A correlation was found between cognitive impairment and SLE disease duration ( p = 0.03).

Conclusions

The rate of MCD-SLE was greater in SLE patients from New York, NY, compared to patients in the Denver, CO, area. The greater duration of disease and higher prevalence of medical complications in the NY group might contribute to this difference. Findings suggest that MCD-SLE may differ by site, but future studies that better evaluate site or selection bias are recommended.

Immune function and brain abnormalities in patients with systemic lupus erythematosus without overt neuropsychiatric manifestations

Objective: This study examined the relationship between immune, cognitive and neuroimaging assessments in subjects with systemic lupus erythematosus (SLE) without histories of overt neuropsychiatric (NP) disorders.

Methods: In total, 84 subjects with nonNPSLE and 37 healthy controls completed neuropsychological testing from the American College of Rheumatology SLE battery. Serum autoantibody and cytokine measures, volumetric magnetic resonance imaging, and magnetic resonance spectroscopy data were collected on a subset of subjects.

Results: NonNPSLE subjects had lower scores on measures of visual/complex attention, visuomotor speed and verbal memory compared with controls. No clinically significant differences between nonNPSLE patients and controls were found on serum measures of lupus anticoagulant, anticardiolipin antibodies, beta 2-glycoproteins, or pro-inflammatory cytokines (interleukin (IL)-1, IL-6, interferon alpha (IFN-alpha), and interferon gamma (IFN-gamma)). Higher scores on a global cognitive impairment index and a memory impairment index were correlated with lower IFN-alpha. Few associations between immune functions and neuroimaging parameters were found.

Conclusions: Results indicated that nonNPSLE patients demonstrated cognitive impairment but not immune differences compared with controls. In these subjects, who were relatively young and with mild disease, no relationship between cognitive dysfunction, immune parameters, or previously documented neuroimaging abnormalities were noted. Immune measures acquired from cerebrospinal fluid instead of serum may yield stronger associations.

Memory impairment associated with neurometabolic abnormalities of the hippocampus in patients with non-neuropsychiatric systemic lupus erythematosus

Objective: Memory impairment is common in patients with systemic lupus erythematosus (SLE). This study examined hippocampal volumes and neurometabolic alterations in relation to memory function in SLE patients without a history of neuropsychiatric syndromes (nonNPSLE).

Methods: Subjects included 81 nonNPSLE patients and 34 healthy controls. Volumetric magnetic resonance imaging and magnetic resonance spectroscopy of the right and left hippocampal areas (RH, LH) were performed. Verbal and visual memory tests were administered and a Memory Impairment Index (MII) was derived from standardized tests.

Results: Higher memory impairment (MII) was correlated with lower RH glutamate + glutamine/creatine ( p = 0.009) and lower RH N-acetylaspartic acid/creatine ( p = 0.012) in nonNPSLE patients. A trend for a negative correlation between RH and LH volumes and MII was evident for absolute hippocampal volumes. Lower RH glutamate + glutamine/creatine was also correlated with worse performance in a mean visual memory index ( p = 0.017).

Conclusions: An association between reduced memory and lower N-acetylaspartic acid/creatine in the RH suggests neuronal damage in nonNPSLE patients with very mild and early disease. Alterations in glutamate + glutamine/creatine further indicate early metabolic changes in nonNPSLE are related to memory impairment, a finding that might suggest that memory impairment relates to presynaptic glutamatergic dysfunction in the hippocampus.

Attention and vigilance functions in normal aging

Clinical observation and considerable research have documented that a slowing of cognitive processing occurs in many healthy older persons. The neuropsychological characterization of this slowing, however, remains unclear, as does its neuroanatomic basis. In a preliminary attempt to help clarify this issue, we conducted two studies with healthy older individuals to evaluate whether declines in immediate and/or sustained attention appear with advancing age. In Study I, 166 subjects aged 50-69 and 70-90 were given several standard tests of immediate attention. No major differences in simple attentional function emerged. In Study II, 38 subjects in the same age ranges were administered tests of sustained attention. Significant differences between groups were seen on a digit cancellation task, despite similar performances on other measures requiring visual scanning and psychomotor speeded responses. The results of the two studies suggest that whereas simple attention tends to remain stable with aging, sustained attention appears to decline after the age of 70. This factor likely contributes to the general slowing of cognition often reported in the elderly, and may be associated with specific age-related neuroanatomic changes.

PRNP H187R mutation associated with neuropsychiatric disorders in childhood and dementia

Described is a large family with an autosomal dominant dementia associated with an H187R mutation in the prion protein gene (PRNP). Clinical features include neuropsychiatric disturbances in childhood and adolescence, dementia in young adulthood with frontotemporal manifestations, and long disease duration. Neuropathology revealed atrophy and mild gliosis, whereas prion protein analysis revealed an abnormal conformer with unusual sensitivity to protease digestion. Mutations in PRNP may cause neuropsychiatric disorders that predate dementia by many years.

Fulminant ascending paralysis as a delayed sequela of diethylene glycol (Sterno) ingestion

The authors report a 57-year-old man who survived 18 days after swallowing an 8-oz. can of Sterno in a suicide attempt. Two days after ingestion, he developed confusion and acute renal failure requiring hemodialysis, followed on day 8 by a delayed but rapidly evolving ascending paralysis. Pathologic examination showed severe demyelination, with lesser axonal damage, of virtually all cranial and peripheral nerves sampled and sparing of central myelin. The diethylene glycol in the Sterno was considered responsible for this intoxication.

CADASIL: neuropsychological findings in three generations of an affected family

Cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) is a hereditary brain disease with a variety of neurologic and psychiatric manifestations. We studied 3 members of a family who each had leukoencephalopathy on neuroimaging studies and a characteristic mutation for CADASIL in the notch 3 region of chromosome 19q12. In all 3 cases, neurobehavioral impairment dominated the clinical picture, and a pattern of psychiatric dysfunction heralding cognitive decline emerged. Neuropsychological evaluation revealed diverse deficits, but a profile of frontal lobe dysfunction, declarative memory impairment suggestive of a retrieval deficit, and relatively preserved language was evident. These cases provide a cross-sectional study of the evolution of CADASIL, and suggest that, as in other diseases characterized by white matter dementia, psychiatric dysfunction may occur initially, followed by pervasive cognitive dysfunction later in the course of the disease. CADASIL should be considered in young adults with unexplained leukoencephalopathy on neuroimaging studies, and in those with neurobehavioral dysfunction and a suggestive family history.

Clinical neurology and executive dysfunction

Executive function is a uniquely human ability that permits an individual to plan, carry out, and monitor a sequence of actions that is intended to accomplish a goal. This crucial neurobehavioral capacity depends on the integrity of the frontal lobes, most importantly the dorsolateral prefrontal cortices and their connections. Executive dysfunction is associated with a wide range of neurologic disorders that affect these regions. In this paper, executive dysfunction is considered from the perspective of behavioral neurology, and the lesion method is employed to illustrate this impairment in a diverse group of disorders. Frontal system damage leading to disturbed executive function is common and clinically significant. Recognition of this syndrome is critical for ensuring the correct diagnosis, accurate prognosis, and appropriate treatment of affected patients. Executive dysfunction also represents an intriguing aspect of brain-behavior relationships and offers important insights into one of the highest cerebral functions.

Toward an understanding of violence: neurobehavioral aspects of unwarranted physical aggression: Aspen Neurobehavioral Conference consensus statement

OBJECTIVE

Violence is a global problem that poses a major challenge to individuals and society. This document is a consensus statement on neurobehavioral aspects of violence as one approach to its understanding and control.

BACKGROUND

This consensus group was convened under the auspices of the Aspen Neurobehavioral Conference, an annual consensus conference devoted to the understanding of issues related to mind and brain. The conference is supported by the Brain Injury Association and by individual philanthropic contributions. Participants were selected by conference organizers to represent leading opinion in neurology, neuropsychology, psychiatry, trauma surgery, nursing, evolutionary psychology, medical ethics, and law.

METHODS

A literature review of the role of the brain in violent behavior was conducted and combined with expert opinion from the group. The major goal was to survey this field so as to identify major areas of interest that could be targeted for further research. Additional review was secured from the other attendees at the Aspen Neurobehavioral Conference.

RESULTS

The group met in the spring of 1998 and 1999 for two 5-day sessions, between which individual assignments were carried out. The consensus statement was prepared after the second meeting, and agreement on the statement was reached by participants after final review of the document.

CONCLUSIONS

Violence can result from brain dysfunction, although social and evolutionary factors also contribute. Study of the neurobehavioral aspects of violence, particularly frontal lobe dysfunction, altered serotonin metabolism, and the influence of heredity, promises to lead to a deeper understanding of the causes and solution of this urgent problem.

N-Methyl-D-aspartate receptor subunit proteins and their phosphorylation status are altered selectively in Alzheimer's disease

The N-methyl-D-aspartate (NMDA) receptor is a subtype of the ionotropic glutamate receptor that plays a pivotal role in synaptic mechanisms of learning and memory. We tested the hypothesis that NMDA receptor protein levels are abnormal in Alzheimer's disease (AD). By immunoblotting, we assessed levels of both non-phosphorylated and phosphorylated receptor subunit proteins from four separate regions of 16 post-mortem brains. Three patient groups with thorough pre-mortem neuropsychological testing were evaluated, including AD, early AD (p-AD), and control patients. Protein levels and phosphorylation status of NMDA receptor subunits NR1, NR2A and NR2B were correlated with measurements of cognitive performance. Selective regional reductions in NMDA receptor subunit protein levels were found in AD compared to controls, but protein levels in the p-AD group were similar to controls. Reductions of NR1 (53%, P<0.05) and NR2B (40%, P<0.05) were identified in hippocampus. Reductions of NR2A (39%, P<0.05) and NR2B (31%, P<0.01) were found in entorhinal cortex. No reductions were noted in occipital cortex and caudate. Phosphorylated NR2A (30%, P<0.05) and NR2B (56%, P<0.01) were selectively reduced in entorhinal cortex in AD when compared to controls. Both phosphorylated and non-phosphorylated NMDA receptor protein levels in entorhinal cortex correlated with Mini-Mental Status Examination (MMSE) and Blessed (BIMC) scores. The losses of phosphorylated and non-phosphorylated NMDA receptor subunit proteins correlated with changes in synaptobrevin levels (a presynaptic protein), but not with age or post-mortem interval. Our results demonstrate that NMDA receptor subunits are selectively and differentially reduced in areas of AD brain, and these abnormalities correlate with presynaptic alterations and cognitive deficits in AD.

Selective regional loss of exocytotic presynaptic vesicle proteins in Alzheimer's disease brains

We tested whether regional or selective alterations in presynaptic proteins occur in Alzheimer's disease (AD) and correlate with tests of cognitive function. We measured the levels of seven presynaptic proteins (synaptobrevin, synaptotagmin, SNAP-25, syntaxin, SV2, Rab3a, and synapsin I) by immunoblotting in postmortem tissue from four brain regions (hippocampus, entorhinal cortex, caudate nucleus, and occipital cortex). Three subject groups were studied: AD, possible/early AD (p-AD), and age-matched controls. Synaptobrevin and synaptotagmin were significantly reduced (29%, P<0.08; 38%, P<0. 07) in hippocampus in p-AD compared to controls. In definite AD compared to controls, selective regional reductions in vesicle proteins were found: synaptobrevin (46%, P<0.05), synaptotagmin (52%, P<0.01), and Rab3a (30%, P<0.05) in hippocampus; synaptobrevin (31%, P<0.01), synaptotagmin (15%, P<0.05), and Rab3a (44%, P<0.05) in entorhinal cortex. In contrast, the levels of two vesicle proteins (synapsin I and SV2) and two presynaptic membrane proteins (syntaxin and SNAP-25) were similar to controls. Synaptobrevin was the only vesicle protein reduced in AD in all four brain regions (occipital cortex 37%, P<0.05; caudate nucleus 31%, P<0.05). By univariate analysis of all cases, Mini-Mental State Examination, Blessed (BIMC) and Free Recall scores were strongly correlated with reduced levels of synaptic vesicle proteins synaptobrevin, synaptotagmin, and Rab3a in hippocampus and entorhinal cortex. These results suggest that there are selective and early defects in presynaptic vesicle proteins, but not synaptic plasma membrane proteins in AD and that defects correlate with cognitive dysfunction in this disease.

Impaired auditory gating and P50 nonsuppression following traumatic brain injury

Traumatic brain injury (TBI) can produce persistent attention and memory impairment that may in part be produced by impaired auditory sensory gating. The P50 evoked waveform response to paired auditory stimuli appears to be a useful measure of auditory gating. The first controlled measurement of the P50 ratio in TBI patients is described: when 20 patients with persistently symptomatic TBI were compared with 20 control subjects, the P50 ratio was significantly greater in the TBI group. The potential neurophysiologic and therapeutic implications of this finding in TBI patients who report symptoms consistent with impaired auditory gating are discussed.

Dementia DDx. Office diagnosis of the four major types of dementia

The prevalence of dementia increases with age from 1% at age 60 to about 40% at age 85. Four types of dementia--Alzheimer's disease, diffuse Lewy body dementia, frontotemporal dementia, and vascular dementia--account for 90% of all cases. The office-based physician can recognize these dementing illnesses in older patients by using existing consensus criteria. Differential diagnosis has an important bearing on patient management and prognosis, due to the potential value of treatment with some medications, possible drug toxicities in certain circumstances, and the complex care needs of patients and their families.

A twin MRI study of size variations in human brain

Although it is well known that there is considerable variation among individuals in the size of the human brain, the etiology of less extreme individual differences in brain size is largely unknown. We present here data from the first large twin sample (N=132 individuals) in which the size of brain structures has been measured. As part of an ongoing project examining the brain correlates of reading disability (RD), whole brain morphometric analyses of structural magnetic response image (MRI) scans were performed on a sample of adolescent twins. Specifically, there were 25 monozygotic (MZ) and 23 dizygotic (DZ) pairs in which at least one member of each pair had RD and 9 MZ and 9 DZ pairs in which neither member had RD. We first factor-analyzed volume data for 13 individual brain structures, comprising all of the neocortex and most of the subcortex. This analysis yielded two factors ("cortical" and "subcortical") that accounted for 64% of the variance. We next tested whether genetic and environmental influences on brain size variations varied for these two factors or by hemisphere. We computed intraclass correlations within MZ and DZ pairs in each sample for the cortical and subcortical factor scores, for left and right neocortex, and for the total cerebral volume. All five MZ correlations were substantial (r's=.78 to.98) and significant in both samples, as well as being larger than the corresponding DZ correlations, (r's=0.32 to 0.65) in both samples. The MZ-DZ difference was significant for 3 variables in the RD sample and for one variable in the smaller control sample. These results indicate significant genetic influences on these variables. The magnitude of genetic influence did not vary markedly either for the 2 factors or the 2 hemispheres. There was also a positive correlation between brain size and full-scale IQ, consistent with the results of earlier studies. The total cerebral volume was moderately correlated (r=.42, p<.01, two-tailed) with full-scale IQ in the RD sample; there was a similar trend in the smaller control sample (r=.31, p<.07, two-tailed). Corrections of similar magnitude were found between the subcortical factor and full-scale IQ, whereas the results for the cortical factor (r=.16 and.13) were smaller and not significant. In sum, these results provide evidence for the heritability of individual differences in brain size which do not vary markedly by hemisphere or for neocortex relative to subcortex. Since there are also correlations between brain size and full-scale IQ in this sample, it is possible that genetic influences on brain size partly contribute to individual differences in IQ.

One and one-half syndrome with supranuclear facial weakness: magnetic resonance imaging localization

OBJECTIVE

To provide clinicoanatomical correlation for a small pontine tegmental ischemic stroke producing the one and one-half syndrome associated with supranuclear facial weakness.

DESIGN

Case report.

SETTING

Tertiary care center.

PATIENT

A 70-year-old man developed left-sided facial weakness sparing the forehead, a left internuclear ophthalmoplegia, and a complete left horizontal gaze palsy immediately after percutaneous transluminal coronary angioplasty. Magnetic resonance imaging demonstrated a small lesion in the left paramedian aspect of the dorsal pontine tegmentum.

MAIN OUTCOME AND RESULTS

Electromyographic findings were consistent with supranuclear facial involvement. The patient had nearly complete recovery after 1 year.

CONCLUSIONS

To our knowledge, this is the first report of supranuclear facial weakness in association with the one and one-half syndrome. The location of the lesion provides evidence of the existence of corticofugal fibers that extend to the facial nucleus in the dorsal paramedian pontine tegmentum.

Brief recall tasks and memory assessment in Alzheimer's disease

Memory measures that permit pattern and error analysis are useful in the differential diagnosis of dementia. However, little is known about the relative utility or relations among verbal memory tests of different lengths. A 6-item verbal learning test (6-VLT) that assesses qualitative performance features was developed and compared to 3-word recall and the California Verbal Learning Test (CVLT) in patients with Alzheimer's disease. Stronger correlations were observed between the 6-VLT and the CVLT. Significant relations were found between 6-VLT and CVLT indexes of learning, recall, and recognition (hits and false positive errors), although free recall errors were unrelated. Brief tasks such as the 6-VLT may provide more useful information regarding gross memory capacity than 3-word recall, although more challenging tasks may be required to elicit characteristic error patterns in Alzheimer's disease.

Brain morphometry in reading-disabled twins

OBJECTIVE

To test for brain structure differences in reading disability (RD) by means of MRI-based morphometry.

BACKGROUND

Consensus is lacking on the brain structural correlates of RD. The current study reports on a wider set of structures in the largest sample yet studied, controlling for age, gender, IQ, and attention deficit hyperactivity disorder (ADHD).

METHODS

A case-control study was performed that was comprised of 75 individuals with RD (mean age, 17.43+/-4.29 years) and 22 control subjects without RD (mean age, 18.69+/-3.75 years), each a single member of a twin pair. The two groups were similar in age, gender, and handedness, but differed in full-scale IQ (FSIQ), with the RD group having a lower mean FSIQ (101.8+/-9.9 versus 118.3+/-10.3). Using three group-by-structure analyses of covariance, groups were compared in terms of volume (in cubic centimeters) of major neocortical subdivisions, subcortical structures, and midsagittal areas (in square millimeters) of three subdivisions of the corpus callosum.

RESULTS

Controlling for age, gender, and IQ, the authors found a significant group-by-structure interaction for the major neocortical subdivisions (p = 0.002), reflecting a different developmental pattern in the RD group, with the insula and anterior superior neocortex being smaller and the retrocallosal cortex being larger in the RD group. In contrast, they found no group main or interaction effects for the subcortical or callosal structures. The pattern of results was essentially the same in subjects without ADHD.

CONCLUSIONS

Most brain structures do not differ in size in RD, but cortical development is altered subtly. This study replicates in a larger sample previous findings of insular differences in RD and demonstrates further that those differences are not attributable to comorbid ADHD.

Toxic leukoencephalopathy

The white matter of the brain is vulnerable to a wide variety of toxins. Leukoencephalopathy is being increasingly recognized in a number of different patient populations. The detection of early and subtle toxin effects has been facilitated by the advent of magnetic resonance imaging, which offers better resolution of white matter than other neuroimaging methods. Neuropathologic features of leukoencephalopathy are also becoming more completely elucidated. Injury to white matter has been described from cranial irradiation and cancer chemotherapeutic drugs, and from a number of other therapeutic agents, drugs of abuse, and environmental toxins. Many patients have reversible leukoencephalopathy, whereas others experience a progressive and irreversible course. Leukoencephalopathy is associated with neurobehavioral manifestations that may be subtle or devastating, and the syndrome of white matter dementia may result. The pathogenesis of toxic leukoencephalopathy remains largely unknown, and treatment is limited in most cases to prevention by avoidance or minimization of the toxin exposure. However, the prognosis for this syndrome may be relatively favorable because of the frequent sparing of axons even when myelin is affected. Toxic leukoencephalopathy is an emerging clinical disorder that presents the opportunity for improving clinical outcomes in a number of patient groups and for achieving a deeper understanding of the role of white matter in cognitive and emotional function.

Cognitive functioning in patients with chronic obstructive pulmonary disease and mild hypoxemia compared with patients with mild Alzheimer disease and normal controls

OBJECTIVE

To examine neuropsychologic functions in patients with chronic obstructive pulmonary disease (COPD) and mild hypoxemia compared with patients with mild Alzheimer disease and normal controls.

BACKGROUND

Cognitive deficits have been documented in patients with COPD, but few studies have compared the neuropsychologic status of these patients with that of other neurologic groups.

METHOD

Cognitive test results from 32 patients with COPD and mild hypoxemia (mean age, 70.3 years; mean education, 13.2 years; mean partial arterial oxygen pressure, 68.8 mm Hg) who had no neurologic symptoms were compared with 31 subjects with mild Alzheimer disease (AD) and 31 normal controls similar in age, education, and sex. Seventy-three percent of the patients with COPD were receiving supplementary oxygen.

RESULTS

Significant group differences across 11 cognitive scores were found using analysis of variance, and post hoc analyses indicated that patients with mild AD performed significantly worse than normal controls and patients with COPD on most tests. The group with COPD and the group with AD demonstrated lower letter fluency compared with controls. Although the patients with COPD performed significantly worse than controls on verbal fluency tasks, they were not in the clinically impaired range, and, overall, the group with COPD was similar to the controls on most cognitive tests.

CONCLUSIONS

These findings suggest that many patients with COPD and mild hypoxemia who don't have neuropsychiatric histories may perform normally on cognitive measures. Oxygen therapy may partially account for preservation of cognitive function in these patients. Results also suggest that patients with COPD and normal controls can be readily distinguished from patients with mild AD based on levels and patterns of neuropsychologic test results. Any significant cognitive deficits in patients with mildly hypoxemic COPD may warrant continued neurologic evaluation.

Frontal lobe lesions and executive dysfunction in children

OBJECTIVE

To investigate the relationship of frontal lobe lesions and neuropsychologic performance in school-aged children to determine whether damage to frontal regions results in specific cognitive sequelae.

BACKGROUND

The role of the frontal lobes in executive function remains incompletely understood, particularly in children.

METHOD

This retrospective study included children aged 8 to 17 with brain lesions of various etiology (n = 63) or diverse psychiatric disorders (n = 48). All were evaluated for details of neurologic and medical history and for scores on the Wechsler Intelligence Scale for Children (WISC-III) and the Wisconsin Card Sorting Test, and all but the psychiatric patients had neuroimaging scans. Five groups were analyzed--dorsolateral frontal, medial-orbital frontal, focal nonfrontal, diffuse, and psychiatric--and neuropsychologic test results were compared using a Kruskal-Wallis nonparametric analysis of variance.

RESULTS

Children with damage to dorsolateral frontal regions were more impaired on the Wisconsin Card Sorting Test than those in all other groups. Comparable performance on the Wechsler scale was found in all groups, suggesting that intellectual functioning did not account for this difference.

CONCLUSIONS

These data provide evidence for a prominent role of the dorsolateral frontal regions in the mediation of executive function in children. They also support the use of the Wisconsin Card Sorting Test in children as a measure of dorsolateral frontal integrity.

White matter dementia in CADASIL

Cerebral white matter disorders may be associated with profound neurobehavioral dysfunction. We report a 62-year-old man who had a slowly progressive 25-year history of personality change, psychosis, mood disorder, and dementia. Neurologic examination disclosed abulia, impaired memory retrieval, and preserved language, with only minimal motor impairment. Neuropsychological testing found a sustained attention deficit, cognitive slowing, impaired learning with intact recognition, and perseveration. Magnetic resonance imaging of the brain revealed extensive leukoencephalopathy. Right frontal brain biopsy showed ill-defined white matter pallor with hyaline narrowing of white matter arterioles. Granular osmiophilic material adjacent to vascular smooth muscle cells on electron microscopy of a skin biopsy, and an arginine for cysteine replacement at position 169 in the 4 EGF motif of the notch 3 region on chromosome 19q12 established the diagnosis of cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL). This case illustrates that CADASIL can manifest as an isolated neurobehavioral disorder over an extended time period. The dementia associated with CADASIL closely resembles that which may occur with other white matter disorders, and represents an example of white matter dementia.

Attention and memory dysfunction after traumatic brain injury: cholinergic mechanisms, sensory gating, and a hypothesis for further investigation

Traumatic brain injury (TBI) is a common occurrence, with a rate of nearly 400,000 new injuries per year. Cognitive and emotional disturbances may become persistent and disabling for many injured persons, and frequently involve symptomatic impairment in attention and memory. Impairments in attention and memory have been well characterized in TBI, and are likely related to disruption of cholinergic functioning in the hippocampus. Additionally, disturbances in this neurotransmitter system may also account for disturbances in sensory gating and discriminative attention in this population. The electroencephalographic P50 waveform of the evoked response to paired auditory stimuli may provide a physiologic market of impaired sensory gating among TBI survivors. The first application of this recording assessment to the TBI population is reported. Preliminary findings in three cases are presented, and the interpretation of impaired sensory gating in this population is discussed. Given the impact of TBI on cholinergic systems, the effects of cholinergic augmentation on attention and memory impairment, and the availability of an electrophysiologic marker of cholinergic dysfunction responsive to cholinergic agents, a testable cholinergic hypothesis for investigation and treatment of these patients is proposed.

Erotomania after aneurysmal subarachnoid hemorrhage: case report and literature review

A woman developed the delusional syndrome of erotomania 4 years after subarachnoid hemorrhage from a ruptured basilar artery aneurysm. The authors review the literature on erotomania in association with neurologic and medical conditions. Although no cause-and-effect relationship can be established between the neurologic event and erotomania in this patient, the possible neuropsychiatric correlates of this syndrome highlight the need for careful attention to neurologic and medical factors in future cases. Available information suggests that diffuse brain dysfunction may contribute to erotomania, perhaps by interfering with the operations of cerebral regions subserving complex emotional function.

The behavioral neurology of cerebral white matter

Behavioral neurology has primarily focused on brain-behavior relations as revealed by disorders of the cerebral cortex and subcortical gray matter. Disorders of cerebral white matter have received less attention. This article considers the contribution of cerebral white matter to normal behavioral function and the effects of white matter disorders on behavior. Diffuse dysfunction is more common than focal impairment, and the term white matter dementia has been proposed as a clinical entity. Conventional neuroimaging has enabled more accurate identification of white matter regions participating in neurobehavioral operations, and newer imaging techniques may define white matter connectivity within and between the hemispheres. As an essential component of neural networks, cerebral white matter contributes to cognitive and emotional functions, and lesions of white matter disconnect these networks to produce neurobehavioral syndromes.

MR enhancing brain lesions in methanol intoxication

Methanol intoxication can cause necrosis of the putamen and subcortical white matter that is evident on neuroimaging. We report a 47-year-old man with significant methanol intoxication who had enhancing lesions in the caudate nuclei, putamina, hypothalamus, and subcortical white matter by MRI. This case demonstrates that contrast enhancement of brain lesions can be observed after methanol poisoning.

Neurobehavioral outcome in pediatric craniopharyngioma

Neurobehavioral dysfunction occurs in children with craniopharyngioma, both before and after treatment, and its impact on outcome may not be fully appreciated. Also unclear is whether neurobehavioral outcome relates more to tumor location or surgical factors. We reviewed the records of 20 children with craniopharyngioma who were seen between 1983 and 1995. All children had subfrontal craniotomy and either partial (14 children) or gross total (6 children) resection of their tumors. In addition to traditional neuropsychological testing, we assessed social behavior and school performance using standardized ratings based on family interviews and school records. Over a mean follow-up period of 38 months, only 3 of 20 children had a good outcome in all three categories, and 12 of 20 had moderate or severe impairment in at least one category. Outcome did not differ between those who had partial and those with gross total resection. We conclude that neurobehavioral disorders are common and cause important morbidity in children after treatment for craniopharyngioma. To evaluate these impairments in future outcome studies, standard neuropsychological testing should be supplemented by specific behavioral assessments to capture the full range of neurobehavioral disability. In this series, partial versus gross total resection did not influence outcome, implying that tumor location in diencephalic and limbic regions is a more important factor.

Education and cognitive function in Alzheimer's disease

In normal aging, an association exists between level of education and verbal abilities. Clinical experience suggests that this relationship may also hold true in Alzheimer's disease (AD). In this study, we examined performance on selected verbal and nonverbal neuropsychological tests in a series of 51 patients with probable AD. Performance on two verbal measures-the National Adult Reading Test-Revised (NART-R) and the Vocabulary subtest from the Wechsler Adult Intelligence Scale-Revised (WAIS-R)-showed strong correlations with level of education. Scores on three nonverbal tests-WAIS-R Block Design, WAIS-R Digit Symbol, and Boston Diagnostic Aphasia Examination clock drawings-were unrelated to education. Consistent with our hypothesis, AD patients with higher premorbid education showed better performance on certain measures of verbal competence. These results indicate that, as in normal aging, education is associated with verbal abilities in AD.

Alzheimer's disease in women

The progressive and irreversible dementia of Alzheimer's disease affects both men and women, but women constitute the majority of persons with the disease. Women may also have relatively more language impairment and a tendency for greater psychiatric involvement. Diagnosis is founded on the recognition of clinical features and exclusion of other causes of dementia. The etiology of the disease remains unknown. Although a variety of genetic factors is increasingly suspected, no diagnostic genetic test is currently recommended. Recent basic science and clinical data suggest the possibility that estrogen may be helpful both in preventing and in treating Alzheimer's disease, and these potential effects may encourage the use of estrogen in postmenopausal women. Standard treatment for Alzheimer's disease involves counseling and support, as well as consideration of tacrine, a cholinergic agent that may stabilize the course in some patients. Until the cause of the disease is elucidated, however, the development of curative treatment is unlikely.

Premorbid intelligence estimation and level of dementia in Alzheimer's disease

Simple sight-word reading tasks have demonstrated utility in the estimation of premorbid intelligence, although the effects of progressive dementia on such tasks has not been thoroughly examined. The present investigation sought to examine estimated IQ scores from the National Adult Reading Test-Revised (NART-R; Blair & Spreen, 1989) in relation to a WAIS-R-based (Wechsler, 1981) estimate of IQ in a series of patients with probable Alzheimer's disease across varying levels of dementia. Results suggest that while NART-R scores do show a decrement with dementia severity, this decline is mild, in contrast to traditionally based IQ scores and other measures of cognitive function, which show more marked declines. Similarly, compared with other tasks, the NART-R showed the strongest correlation with education across the sample as a whole, while the other indices were more related to level of dementia. These findings support the use of measures such as the NART-R in estimating premorbid intellectual functioning in patients at various levels of dementia severity, including those with more advanced cognitive deterioration.

Ethical concerns in the use of palliative drug treatment for Alzheimer's Disease

The cases of 3 patients with Alzheimer's disease (AD) who had varied outcomes from treatment with tacrine or other palliative drugs illustrate the need to consider the benefits of such agents for each case on an individual basis. In the absence of a cure, the most important factor in the care of AD patients may be the physician's attitude that irreversibility does not imply untreatability.

Neuropsychiatric features of Lewy body disease

Although traditionally associated with Parkinson's disease, the eosinophilic intracytoplasmic neuronal inclusion known as the Lewy body has recently been regarded as the primary neuropathologic finding in a variety of conditions affecting the aging brain. The term Lewy Body Disease (LBD) will be used in this review to refer to a spectrum of clinical states varying from those due to incidental or mildly symptomatic histopathologic changes to progressive dementia and psychosis. Many unanswered questions remain about the neurobehavioral and neuropathological implications of Lewy bodies, but it is useful to consider the LBD spectrum in terms of the variable effects on neuropsychiatric function that can be observed clinically.

Alzheimer's disease: it's irreversible but not untreatable

Alzheimer's disease (AD) poses a major clinical challenge because of its high prevalence in the aging population, its prolonged course, and the absence of curative treatment. Important advances have recently been made, however, in the diagnosis of the disease and the elucidation of its neuroscientific basis. Genetic research has identified an allele of apolipoprotein E that may confer a higher risk of developing AD. In addition, new possibilities for treatment are being investigated. One drug therapy--tacrine--has been approved, although uncertainty lingers about its efficacy and safety. In the absence of effective medical treatment, AD is a difficult problem for patients and their families. However, the physician can help by providing emotional support, symptom management, and informed counseling.

Neurobehavioral presentations of brain neoplasms

We studied 8 patients with frontal or temporolimbic neoplasms who had psychiatric presentations to clarify diagnostic criteria for distinguishing psychiatric disease from structural brain lesions and to examine brain-behavior relationships associated with cerebral neoplasms using modern neuroimaging techniques. Medical records were retrospectively reviewed for evidence of neurobehavioral and neurologic manifestations, tumor histologic features, and the results of treatment. Clinical presentations were correlated with tumor location as determined by computed tomography and magnetic resonance imaging. Patients with frontal lobe tumors presented with abulia, personality change, or depression, whereas those with temporolimbic tumors had auditory and visual hallucinations, mania, panic attacks, or amnesia. After treatment, neurobehavioral syndromes abated or resolved in 7 of 8 patients. We recommend that any patient 40 years of age or older with a change in mental state, cognitive or emotional, should have neuroimaging of the brain. Any patient with a psychiatric presentation who has specific neurobehavioral or neurologic findings or an unexpectedly poor response to psychopharmacologic treatment should also have brain imaging. These case reports extend and update observations on the importance of frontal and temporolimbic systems in the pathogenesis of neurobehavioral disorders.

Acute arcuate fiber demyelinating encephalopathy following Epstein-Barr virus infection

We describe a patient who presented with an acute monophasic illness characterized by behavioral abnormalities, visual illusions, and a seizure, who had magnetic resonance- and brain biopsy-documented evidence of multifocal central nervous system demyelination. Serological studies were diagnostic of recent Epstein-Barr virus infection and included evidence of intrathecal synthesis of Epstein-Barr virus-specific IgG antibodies against the viral capsid antigen. Viral DNA could not be amplified from cerebrospinal fluid by polymerase chain reaction, and viral antigen and genome were not detected in the brain biopsy specimen. The patient's clinical course, diagnostic studies, and neuropathological findings all support the diagnosis of a postinfectious Epstein-Barr virus-mediated demyelinating encephalopathy.

Episodic memory function in advanced aging and early Alzheimer's disease

Despite some well-documented differences, normal aging and Alzheimer's disease (AD) share a number of common neuropathological and neuropsychological features. Many of the reported differences are largely quantitative in nature and there is often overlap between the respective distributions of these populations. To assess the issue of overlap and distinguishing features in memory functions between these groups, and to minimize aging effects per se, samples of older individuals in good health (ages 75-95 yr) and younger patients in the early stages of AD (age < 75 yr) were selected to be similar in global cognitive functioning. Despite comparable language and visuospatial scores, these preliminary results suggest important qualitative differences in episodic memory functions between these conditions, even when "low-functioning" or "at-risk" controls are compared with early AD patients. These findings furthermore highlight some of the challenges in defining "normality" among the oldest segment of our population.

Reduced platelet cytochrome c oxidase activity in Alzheimer's disease

We evaluated a simplified method for preparation and analysis of platelet cytochrome c oxidase activity in Alzheimer's disease (AD) and control patients. Mean cytochrome c oxidase activity in controls (n = 17) was 0.233 sec-1/mg whereas mean cytochrome c oxidase activity in Alzheimer patients (n = 19) was 0.193 sec-1/mg, p = 0.033. Complex III (ubiquinol:cytochrome c oxidoreductase), complex II (succinic dehydrogenase), and citrate synthase were all assayed as internal controls and were not significantly different in controls and Alzheimer patients. There is a relatively specific loss of platelet cytochrome c oxidase activity in Alzheimer disease patients.

Electron transport chain defects in Alzheimer's disease brain

Previous work suggested a deficiency in the terminal complex of the mitochondrial electron transport chain, cytochrome c oxidase (COX), in platelet mitochondria of Alzheimer's disease (AD) patients. The present study extends this observation to AD brain mitochondria through assay of electron transport chain activities in mitochondria isolated from autopsied brain samples from AD patients (n = 9) and from controls with and without known neurologic disease (n = 8). AD brain mitochondria demonstrated a generalized depression of activity of all electron transport chain complexes. This depression was most marked in COX activity (p < 0.001). Concentrations of cytochromes b, c1, and aa3 were similar in AD and controls. The electron transport chain is defective in AD brain, and the defect centers about COX.

Non-Alzheimer fronto-temporal degenerative dementia. A neurobehavioral and pathologic study

In contrast to Alzheimer's disease (AD), which predominantly affects the limbic system and association neocortex, degenerative dementias have been identified that show greatest damage in frontal and temporal neocortex. This "lobar atrophy" was first described by Arnold Pick over 100 years ago. We present four autopsy-documented, non-AD cases of fronto-temporal degeneration (FTD), each with neurobehavioral assessment. Three of the patients presented with personality change and the fourth with non-fluent aphasia; memory was initially preserved in all, and only later did dementia become evident. At autopsy, the hippocampi were relatively spared in all cases. One patient had classic Pick-body temporal lobe Pick's disease (PD), 2 had frontal lobe-predominant atrophy with severe degeneration of caudate and substantia nigra (so-called "generalized Pick's"), and the fourth had temporal lobe degeneration without Pick bodies or cells. We propose that subgroups of FTD be categorized both by microscopic features and gross patterns of atrophy, and that subgroups of FTD be kept separate for neurochemical and genetic studies. Neurobehavioral and neuropsychological evaluation early in the course of unusual degenerative dementia can aid in distinguishing FTD cases from AD patients for clinical and drug studies.

Early detection of fronto-temporal degeneration by clinical evaluation

Although Alzheimer's Disease (AD) is the most common degenerative dementia, other neuropathological processes are well known to cause dementia syndromes. Fronto-temporal degeneration (FTD) is one such entity, and often produces a clinical presentation distinct from that of AD. Some FTD cases are shown at autopsy to be classic Pick's Disease, but others defy precise classification at this point because they lack characteristic Pick bodies. We describe a case of putative FTD in a 54-year-old man with personality change and complete Klüver-Bucy syndrome. Neuropsychological evaluation disclosed evidence of extensive frontal system dysfunction, with lesser problems in memory, language, and visuospatial skills. Magnetic resonance imaging studies after 17 months of the illness were largely nonspecific, but a follow-up scan 16 months later revealed bifrontal and bitemporal atrophy with ventricular enlargement. Neuromorphometric analysis suggested an increase in cortical atrophy and ventricular dilation over time. This case emphasizes the value of careful clinical evaluation in unusual non-AD degenerative dementias and suggests that neuroimaging studies may be less sensitive in the early diagnosis of such cases.

Alcohol- and drug-related neurotoxicity

The nervous system is vulnerable to a wide range of toxic insults. Historically, the toxic syndromes most often encountered have involved drugs of abuse, most notably alcohol. Cocaine has also been securely identified in recent years as neurotoxic. Equally distressing are neurotoxic disorders resulting from the administration of drugs for other conditions, and a growing literature is documenting these effects as well. This review discusses the cerebral basis of drug abuse and then considers recent data on the neurotoxicity of ethanol, methanol, and cocaine. Finally, selected examples of iatrogenic drug effects illustrate the variety of toxic syndromes that can occur with commonly employed treatment modalities.

Neuroleptic medications inhibit complex I of the electron transport chain

Neuroleptic medications are prescribed to millions of patients, but their use is limited by potentially irreversible extrapyramidal side effects. Haloperidol shows striking structural similarities to the neurotoxin 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine, which produces parkinsonism apparently through inhibition of NADH:ubiquinone oxidoreductase (complex I) of the mitochondrial electron transport chain. We now report that haloperidol, chlorpromazine, and thiothixene inhibit complex I in vitro in rat brain mitochondria. Clozapine, an atypical antipsychotic reported to have little or no extrapyramidal toxicity, also inhibits complex I, but at a significantly higher concentration. Neuroleptic treated patients have significant depression of platelet complex I activity similar to that seen in idiopathic Parkinson's disease. Complex I inhibition may be associated with the extrapyramidal side effects of these drugs.