Evidence for early central nervous system involvement in the acquired immunodeficiency syndrome (AIDS) and other human immunodeficiency virus (HIV) infections. Studies with neuropsychologic testing and magnetic resonance imaging

Although a high prevalence of central nervous system disease is seen in persons with the acquired immunodeficiency syndrome (AIDS), the natural history of brain involvement with human immunodeficiency virus (HIV) remains poorly understood. Neuropsychologic evaluations of 55 ambulatory homosexual men revealed abnormalities in 13 of 15 with AIDS, 7 of 13 [corrected] with AIDS-related complex, 7 of 16 [corrected] with HIV-seropositivity only, and 1 of 11 with HIV-seronegativity. Common neuropsychologic problems included impaired abstracting ability, learning difficulties, and slowed speed of information processing. Magnetic resonance imaging had abnormal findings in 9 of 13 patients with AIDS and 5 of 10 patients with AIDS-related complex who were available for scans. The commonest abnormalities were sulcal and ventricular enlargement and bilateral patchy areas of high signal intensity in the white matter. We postulate that central nervous system involvement by HIV may begin early in the course of AIDS and cause mild cognitive deficits in otherwise asymptomatic persons.

Reduced temporal limbic structure volumes on magnetic resonance images in first episode schizophrenia

Pathomorphology of the limbic system has been described in post-mortem studies of schizophrenia. To determine whether this could be detected in living patients and was not secondary to the treatment or the chronicity of the disease itself, we measured the volumes of the hippocampus-amygdala complex and adjoining temporal horns of 34 patients in their first episode of schizophrenia and 25 normal volunteers using T1 weighted contiguous coronal magnetic resonance images of 3.1 mm width. The results demonstrate abnormal medial temporal lobe morphology in a subgroup of patients at the onset of their illness. There were clear laterality effects and sex differences: hippocampal tissue was significantly smaller only in the left hemisphere of male patients, whereas enlargement of the whole temporal horn or its anterior portion was present on the left side in both sexes. Dysfunction of the limbic mesiotemporal structures might explain some of the clinical features of the disease.

Glial cell abnormalities in major psychiatric disorders: the evidence and implications

Recent quantitative post-mortem investigations of the cerebral cortex have convincingly demonstrated cortical glial cell loss in subjects with major depression. Evidence is also mounting that glial cell loss may also be a feature of schizophrenia. These findings coincide with a re-evaluation of the importance of glial cells in normal cortical function. In addition to their traditional roles in neuronal migration and inflammatory processes, glia are now accepted to have roles in providing trophic support to neurons, neuronal metabolism, and the formation of synapses and neurotransmission. Consequently, reduced cortical glial cell numbers could be responsible for some of the pathological changes in schizophrenia and depression, including reduced neuronal size, reduced levels of synaptic proteins, and abnormalities of cortical neurotransmission. Additionally, as astrocytes provide the energy requirements of neurons, deficient astrocyte function could account for aspects of the functional magnetic imaging abnormalities found in these disorders. We discuss the possible basis of glial cell loss in these disorders and suggest that elevated levels of glucocorticoids, due to illness-related stress or to hyperactivity of the hypothalamic-pituitary-adrenal may down-regulate glial activity and so predispose to, or exacerbate psychiatric illness through enhanced excitotoxicity. The potential therapeutic impact of agents which up-regulate glial activity or normalise glial cell numbers is also discussed.

Parkinson disease, dementia, and Alzheimer disease: clinicopathological correlations

Clinical records and neuropathological specimens from 36 patients with autopsy-demonstrated idiopathic Parkinson disease (PD) were reviewed independently and the results compared. Nine (31%) of the 29 patients with adequate clinical data had severe dementia and 7 (24%) had mild dementia. The cerebral cortex showed senile plaques and fibrillary tangles in 15 of the 36 patients (42%). These changes were found in all 9 patients with severe dementia, in 3 of the 7 with mild dementia, and in 3 of the 13 patients with normal mental status. The prevalence of pathologically established Alzheimer changes and dementia among the patients with PD (33%) was over six times that found in an age-matched population (5.1%). Survival after the onset of PD with Alzheimer disease was shorter than in PD without Alzheimer disease.

Obstetric complications, neurodevelopmental deviance, and risk of schizophrenia

It is concluded from a review of the literature and a pilot survey that schizophrenic patients more frequently have a history of obstetric complications (OCs) than do other psychiatric patients and normal subjects. OCs are associated with increased cerebral ventricular size in both infancy and adulthood, and are more common among non-familial schizophrenic patients. Neonatal cerebrovascular events consequent upon OCs provide a mechanism to explain the increased risk of neurodevelopmental deviance and later schizophrenia.

Ventricular enlargement in schizophrenia: relationship to positive and negative symptoms

The authors explored the clinical correlates of ventricular enlargement in schizophrenia by comparing 16 patients with "large" ventricles (ventricles more than I SD above the control mean) with 16 patients with the smallest ventricles from a sample of 52 schizophrenic patients. Patients with ventricular enlargement showed some impairment in the sensorium and had a preponderance of "negative" symptoms (e.g., alogia, affective flattening, avolition, anhedonia), while those with small ventricles were characterized by "positive" symptoms (e.g., delusions, hallucinations, positive formal thought disorder, bizarre behavior). These findings suggest that combining a measure of brain structure with the clinical picture may provide a useful new approach to the classification of schizophrenia.

Schizophrenia and the brain: a prospective clinico-neuropathological study

The neuropathological results from a prospective, systematically assessed, series of 56 schizophrenic patients and 56 age- and sex-matched normal controls have been presented. When compared with the normal controls, the brains of the schizophrenic subjects showed a significant reduction in brain weight and brain length with a concomitant increase in ventricular size. (All findings relate to measurements made after formalin fixation). In addition, the brains of the schizophrenic patients contained significantly more non-specific focal pathology and fibrillary gliosis than the controls. After exclusion of cases with moderate and severe Alzheimer-type change, cerebro-vascular disease and all forms of focal pathology, the structural brain changes (i.e. decrease in brain weight and brain length) continued to distinguish the schizophrenia group from the controls. Furthermore, an analysis of the clinical data showed that the structural brain changes were correlated in the schizophrenic patients with a measurement of pre-morbid function. The findings and their possible aetiological implications have been discussed.

Neuropsychology of multiple sclerosis

Neuropsychological investigations have demonstrated that cognitive disorders are common (45-65%) in patients with multiple sclerosis. This review summarizes our current understanding of the nature and etiology of these disorders. Specifically, neuropsychological deficits regularly occur on measures of recent memory, attention, information-processing speed, executive functions, and visuospatial perception. In contrast, general intelligence, language, and certain aspects of memory (short-term capacity and implicit) are preserved. The degree and pattern of cognitive dysfunction is highly correlated with the amount and location of white-matter disease within the cerebral hemispheres. Natural history studies indicate that changes in cognitive test performance are correlated with increasing lesion load on magnetic resonance imaging. The development of brief cognitive-testing instruments for clinical screening and measuring treatment effects in clinical trials is underway. A clear weakness in the literature is the dearth of studies evaluating potential treatments for cognitive disorders.

Reduced neuronal size in posterior hippocampus of schizophrenic patients

The hippocampus, an integral component of the corticolimbic circuitry of the brain, has been recently implicated in the pathophysiology of schizophrenia. This article has employed quantitative morphometric techniques to determine whether abnormalities of posterior hippocampal cross-sectional area, as well as the number, size, and degree of disarray of pyramidal neurons were present in 9 control and 14 schizophrenic subjects. Seven schizophrenic patients showed evidence of superimposed mood disturbance (schizoaffective type), while the remaining seven were a mixture of paranoid, undifferentiated, and catatonic types. All morphometric measurements were conducted under strictly blind conditions; stepwise multiple regression and analyses of covariance were used to evaluate the effects of various confounding variables. There were no differences in the cross-sectional size of the hippocampus or degree of neuronal disarray between the two groups. Similarly, the number of pyramidal neurons was also the same in sectors Cornu Ammonis (CA) 2, CA 3, and CA 4 for the controls and schizophrenic subjects. In CA 1, the schizophrenic subjects without mood disturbances showed a significant reduction (36%) of pyramidal neuron numbers when compared with those of both controls and patients with mood disturbance. Pyramidal neurons were smaller in all sectors of the schizophrenic specimens, CA 1 (p less than or equal to 0.01), CA 2 (p less than or equal to 0.01), CA 3 (p less than or equal to 0.01), and CA 4 (p less than or equal to 0.005), but there were no differences with respect to the presence of mood disturbances. Corrections for the effects of age, postmortem interval, fixation interval, hypoxia, and neuroleptic exposure did not alter the pattern in the data. The significance of a smaller size of hippocampal pyramidal neurons in this group of schizophrenic specimens is unclear, but it is consistent with the suggestions of other laboratories that there may be altered function of this brain region in chronically psychotic individuals.

A magnetic resonance imaging study of putamen nuclei in major depression

The basal ganglia are recognized as putative mediators of certain cognitive and behavioral symptoms of major depression. Moreover, patients with basal ganglia lesions have repeatedly exhibited significant affective symptomatology, including apathy, depressive mood, and psychosis. Using high resolution, axial T2 intermediate magnetic resonance images, and a systematic sampling stereologic method, we assessed putamen nuclei volumes in 41 patients with major depression (DSM-III) and 44 healthy volunteer controls of similar age. Depressed patients had significantly smaller putamen nuclei compared with controls. Age was negatively correlated with putamen size in both groups. These results are the first demonstration of diminished putamen volumes in depression and further support a role for basal ganglia structures in the etiopathogenesis of depression.

Fatty acid levels in the brains of schizophrenics and normal controls

Essential fatty acids are important constituents of the brain. There is evidence that levels in blood of certain essential fatty acids and their eicosanoid derivatives may be abnormal. We now report that in the frontal cortex of schizophrenic patients there are significant differences from normal in the fatty acid composition of phosphatidylethanolamine. These differences from normal were not found in the cerebellar cortex.

Temporal lobe structure as determined by nuclear magnetic resonance in schizophrenia and bipolar affective disorder

Temporal lobe structure has been assessed by magnetic resonance imaging in groups of patients with schizophrenia (n = 21) bipolar affective disorder (n = 20) and normal controls (n = 21). In the temporal lobe area a significant (p less than 0.05) diagnosis by side interaction was present, the area being less on the left than on the right side in patients with schizophrenia in contrast to findings in the two other groups. Lateral ventricular and temporal horn area did not distinguish the groups as a whole. However, there was a significant (p less than 0.05) relationship between lateral ventricular area and poor outcome, and in an analysis confined to males, patients with schizophrenia (n = 15) were found to have significantly (p less than 0.05) enlarged temporal horns.

Schizophrenia: a neuropathological perspective

It is probable that all schizophrenics have abnormalities in the medial temporal lobe, which differ in degree but not in kind. The structures of the medial temporal lobe are believed to have a crucial role in the integration and processing of the output from the association cortex. Dysfunction of this system could result in the clinical symptoms that form the core of the schizophrenia syndrome. The structural differences appear to fit the profile of a disturbance in the normal pattern of brain development. The asymmetrical patterns of normal brain development explain how such a disturbance simultaneously affecting both hemispheres could, disproportionately, affect the left (dominant) hemisphere. Epidemiological and pathological evidence points to aberrant genetic mechanisms as being the cause of the developmental anomaly in the majority of cases; environmental factors probably play a minor role. Despite the great progress made in solving the enigma of the structural changes in the brains of schizophrenics, the cause(s) of the changes--the aberrant genetic mechanism controlling brain development--may prove difficult to define.

Problems with ratio and proportion measures of imaged cerebral structures

Ratio measures, such as the ventricle-brain ratio (VBR) based on computed tomography or magnetic resonance imaging, are widely used in psychiatric research in studies of brain function and morphology. While imaging techniques have advanced considerably, the form of the index of a structure's size has remained the same--a proportion based on an estimate of the structure's size divided by a like estimate of the whole brain size. We demonstrate that ratio and similar indices can suffer greatly in reliability when compared with simple volume measures. This loss of reliability is related to the relation of a structure's size and whole brain size. We review various methods for measuring the size of structures and discuss their strengths and limitations in terms of reliability and validity. In many instances, other methods of "correcting" for brain size (e.g., regression or covariance) may yield measurements that are more appropriate than ratios.

Magnetic resonance and computed tomographic imaging in the evaluation of acute neuropsychiatric disease in systemic lupus erythematosus

Magnetic resonance (MR) imaging and computed tomography (CT) are useful for the evaluation of central nervous system (CNS) lupus. This report describes the use of cranial MR and CT in 21 patients with systemic lupus erythematosus (SLE) with acute neuropsychiatric symptoms manifested by headache, seizures, focal neurological deficits, psychosis, or organic brain syndrome. Computed tomography was found to be insensitive and detected only diffuse atrophy (two cases), cerebral infarct (one case), and intracerebral haemorrhage (one case) in the 21 patients. Cranial MR images obtained with a General Electric 1.5 tesla Signa unit detected labile and fixed areas of increased proton intensity interpreted as focal oedema (eight cases), infarct (10 cases), haemorrhage (one), atrophy (seven), and acute sinusitis (two). Focal oedema was characterised by labile, high intensity lesions in the gray or white matter of the cerebellum, cerebrum, or brain stem, which completely resolved after aggressive corticosteroid treatment. Most high intensity reversible or fixed lesions evident on MR were not apparent on cranial CT images. In several patients sequential MR images were valuable in monitoring the efforts of treatment. Although histological confirmation of the high intensity brain lesions apparent on MR is desirable, prior necropsy studies suggest that pathological confirmation may be difficult owing to the paucity of recognisable brain lesions in patients with CNS lupus. It is concluded that for the evaluation of acute neuropsychiatric SLE MR is useful and provides more information than cranial CT.

The structure of cognition in 9 and 10 year-old children and associations with problem behaviors: Findings from the ABCD study's baseline neurocognitive battery

The Adolescent Brain Cognitive Development (ABCD) study is poised to be the largest single-cohort long-term longitudinal study of neurodevelopment and child health in the United States. Baseline data on N= 4521 children aged 9-10 were released for public access on November 2, 2018. In this paper we performed principal component analyses of the neurocognitive assessments administered to the baseline sample. The neurocognitive battery included seven measures from the NIH Toolbox as well as five other tasks. We implemented a Bayesian Probabilistic Principal Components Analysis (BPPCA) model that incorporated nesting of subjects within families and within data collection sites. We extracted varimax-rotated component scores from a three-component model and associated these scores with parent-rated Child Behavior Checklist (CBCL) internalizing, externalizing, and stress reactivity. We found evidence for three broad components that encompass general cognitive ability, executive function, and learning/memory. These were significantly associated with CBCL scores in a differential manner but with small effect sizes. These findings set the stage for longitudinal analysis of neurocognitive and psychopathological data from the ABCD cohort as they age into the period of maximal adolescent risk-taking.

Schizophrenia and the hippocampus: the embryological hypothesis extended

Recent studies suggest that consistent structural changes exist in the hippocampi of schizophrenic patients. These alterations are characterized by a significant degree of disorientation of the hippocampal pyramidal cells when compared with age-matched nonschizophrenic controls. The degree of neuronal disorientation seems to correlate positively with the severity of the clinical picture. A hypothesis on the pathogenesis of this process, suggested in an earlier article, is extended here. Putative maternal infection with one of several neuraminidase-bearing viruses, especially during the second trimester of pregnancy, may severely affect the migration of primitive neurons into the primordial hippocampus. The "neuraminidase effect," expressed through alteration of the normal sequential patterns of N-CAM (neuronal-cell adhesion molecule) maturation, may result in the cellular disarray we have noted. This alteration may prove useful as a cell marker for schizophrenia, even though its actual relation to clinical symptomatology has still to be evaluated. Genetic factors also are believed to be involved, perhaps in the form of certain patterns of reduced immunocompetence, which might render the mother more susceptible to viral infection.

Neurobiological investigations in cingulate cortex of schizophrenic brain

Several studies have indicated that the pathophysiology of schizophrenia may involve discrete alterations of intrinsic circuits within the anterior cingulate cortex, particularly in layer II. These findings have suggested the possibility that a disturbance in neuronal migration or differentiation during the perinatal period could be related to these differences in schizophrenia subjects. To explore the idea that schizophrenia may be a neurodevelopmental disorder in which precise changes in synaptic connectivity occur, model circuits can be used as empirical tools for identifying the nature and origin of layer II abnormalities in the cortex of schizophrenic brain. Eventually, a strategy of this type may point the way to novel treatment approaches that will limit or perhaps even prevent the deterioration that occurs in patients with schizophrenia.

Progressive diffuse leukoencephalopathy in patients with acquired immune deficiency syndrome (AIDS)

Two adult patients with acquired immune deficiency syndrome (AIDS) presented with psycho-organic symptoms produced by an extensive cerebral and cerebellar leukoencephalopathy. Diffuse loss of myelin and axons with reactive astrocytosis and distinctive multinucleated giant cells were prominent in the deep white matter, but less so in the subcortical white matter and in compact myelinated pathways. Bilateral involvement of the centrum semiovale produced distal Wallerian degeneration of the descending pyramidal tracts, which in one patient correlated with progressive paraparesis and bladder dysfunction. Although there were morphological indications of cytomegalovirus infection and immunohistochemical evidence of papovavirus antigens, the neuropathology did not resemble that usually associated with infection by these opportunistic agents. The possibility is entertained that the progressive diffuse leukoencephalopathy (PDL) in these patients was directly related to infection with human T-cell lymphotropic virus (HTLV-III/LAV), the etiologic agent of AIDS.

Caudate, putamen, and globus pallidus volume in schizophrenia: a quantitative MRI study

Basal ganglia structures have been reported to be abnormal in schizophrenia. However, while component structures of the basal ganglia are functionally differentiated, there have been no evaluations of their separate magnetic resonance imaging (MRI) volumes with small voxel (1.5 mm3) spoiled gradient-recalled acquisition in steady state techniques and multi-plane assessments. We examined MRI scans from 15 male, right-handed, neuroleptic-medicated schizophrenic patients and 15 age-, handedness-, and gender-matched normal volunteers. Compared with normal subjects, schizophrenic patients showed enlarged volumes: 14.2% for total basal ganglia, 27.4% for globus pallidus, 15.9% for putamen, and 9.5% for caudate. Increased volumes, especially of the caudate, were associated with poorer neuropsychological test performance on finger tapping and Hebb's Recurring Digits. These findings indicate abnormalities throughout all basal ganglia structures in at least a subgroup of schizophrenic patients.

Developmentally moderated expressions of the neuropathology underlying schizophrenia

A gradually accumulating body of literature suggests that behavioral dysfunction precedes the onset of the schizophrenic syndrome by many years. Thus, a comprehensive neurodevelopmental model of schizophrenia must encompass these early manifestations of dysfunction as well as the postmorbid period. This article draws on previous research findings as well as recently proposed neurodevelopmental models to offer some further hypotheses about the neurodevelopmental process underlying the changing life-course manifestations of the diathesis for schizophrenia. It is proposed that normal maturational events in the central nervous system moderate the behavioral expression of a congenital neuropathology that affects subcortical regions of the brain that are part of multiple neural circuits. Specifically, it is suggested that the diathesis for schizophrenia involves a functional excess of dopamine activity in the basal ganglia that serves to disrupt these circuits. Findings from empirical research suggest a modal developmental trajectory for schizophrenia in which neuromotor dysfunction is most pronounced in early childhood and late in life, whereas florid psychotic symptomatology is most pronounced in late adolescence and early adulthood. The literature on normal central nervous system development suggests that the feedback circuit linking motor cortex with subcortical structures is maximally metabolically activated, relative to other circuits, early and late in the life course. Thus, subcortical dopamine excess may be predominantly expressed in motoric symptoms during these periods. In contrast, late adolescence and early adulthood are marked by low motor cortex metabolic activity relative to other cortical regions, in particular limbic and frontal regions. In addition, hormonal changes appear to result in a maximal activation of the dopamine system during this developmental period. Thus, it is hypothesized that during this period the neural circuitry abnormality will be primarily behaviorally expressed in psychotic symptoms. Some implications of the model for the study of movement abnormalities and psychotic symptoms are discussed.

Ventricular enlargement in poor-outcome schizophrenia

BACKGROUND

A subset of patients with schizophrenia, defined on the basis of longitudinal deficits in self-care, may show a classic ("Kraepelinian") degenerative course. An independent validator of the phenomenologically defined Kraepelinian subtype might be provided by a structural indicator of possible brain degeneration: ventricular size as measured by computed tomography (CT).

METHODS

To examine whether Kraepelinian patients would show a differential increase in ventricular size over time, two CT scans were conducted at intervals separated by > 4 years, an average of 5 years. Fifty-three male patients with DSM-III-R diagnoses of chronic schizophrenia were subdivided into Kraepelinian (n = 22; mean age = 42 +/- 6 years) and non-Kraepelinian (n = 31; mean age = 38 +/- 12.2 years) subgroups. Kraepelinian patients were defined on the basis of longitudinal criteria: > 5 years of complete dependence on others for life necessities and care, lack of employment, and sustained symptomatology. Thirteen normal elderly volunteers (mean age = 60 +/- 17.8) were also scanned at 4-year intervals. CT measurements were made by raters without knowledge of subgroup membership. A semiautomated computer program was used to trace the anterior horn, lateral ventricles, and temporal horns for each slice level on which they were clearly seen.

RESULTS

The ventricles showed a bilateral increase in size over the 4-year interval in the Kraepelinian subgroup, more marked in the left hemisphere than the right. By contrast, neither the non-Kraepelinian subgroup nor the normal volunteers showed significant CT changes from scan 1 to scan 2.

CONCLUSIONS

Thus, the longitudinal dysfunctions in self-care that characterize the Kraepelinian patients were associated with an independent indicator of brain abnormality.

Neuropathological correlates of psychotic phenomena in confirmed Alzheimer's disease

BACKGROUND

The prevalence of psychotic phenomena in confirmed Alzheimer's disease (AD) and their potential neuropathological correlates have rarely been the subject of prospective investigation.

METHOD

Psychopathological disturbances were recorded prospectively according to the Geriatric Mental State Schedule and the CAMDEX: The frequency of these phenomena and neuropathological changes were examined in 56 patients with definite AD.

RESULTS

Hallucinations had been documented in 13 patients, paranoid delusions in 9 and delusional misidentification (e.g. the Capgras-type and the 'phantom boarder' symptoms) in 14 patients. Misidentifications were associated with lower neurone counts in the area CA1 of the hippocampus. Delusions and hallucinations were observed in patients with less severe cell loss in the parahippocampal gyrus and with lower cell counts in the dorsal raphe nucleus. A decrease of neurones in the locus coeruleus in a subset of depressed patients with AD had been reported earlier. Delusions and delusional misidentification were common in 5 patients with basal ganglia mineralisation, but there was no statistically significant association of these symptoms with the presence of Lewy bodies in the brainstem and neocortex of our patient sample.

CONCLUSIONS

These findings are compatible with the view that morphological changes in certain brain areas may promote the development of psychotic phenomena in AD. AD may offer a model for the understanding of pathomechanisms underlying the development of psychopathological disturbances in other psychoses with more discrete neuropathological changes.

Ventricular enlargement in schizophrenia. A meta-analysis of studies of the ventricle:brain ratio (VBR)

Multivariate meta-analysis was performed on 39 studies of ventricular size in schizophrenia which used the ventricle:brain ratio (VBR). The size of the VBR was dependent both upon the date when studies were carried out (more recent studies showing a reduction in the difference between schizophrenics and controls), and upon the diagnostic criterion used in the studies. Methodological factors in study design seemed more important than the characteristics of the schizophrenic subjects, in determining the VBR. Our analysis suggests that there is a difference in VBR between schizophrenics and controls which would seem to be an indisputable characteristic of schizophrenia. However, the difference is smaller than has previously been thought, so that, although of undoubted theoretical interest in accounting for the aetiology of schizophrenia, it is probably too small to be of practical significance in diagnosis, or in the differentiation of subtypes.