The pitch-deviant MMN reductions present in patients with chronic schizophrenia are not present at first hospitalization. The sensory, echoic memory functions indexed by MMN seem unaffected early in the schizophrenia disease process. Reductions in MMN amplitude may develop over time and index the progression of the disorder, although that can only be definitively determined by longitudinal assessments.

Our findings suggest that a deficit in use of effective strategies influences episodic memory performance in schizophrenia and that abnormalities in functional brain activation persist even when such strategies are applied.

IntroductionBetter characterization of the relationship between episodic memory and hippocampal volumes is crucial in early detection of neurodegenerative disease. We examined these relationships in a memory clinic population.MethodsParticipants (n = 226) underwent structural magnetic resonance imaging and tests of verbal (Hopkins Verbal Learning Test-Revised, HVLT-R) and non-verbal (Brief Visuospatial Memory Test-Revised, BVMT-R) memory. Correlational analyses were performed, and analyses on clinical subgroups (i.e., amnestic Mild Cognitive Impairment, non-amnestic Mild Cognitive Impairment, probable Alzheimer’s disease, intact memory) were conducted.ResultsPositive associations were identified between bilateral hippocampal volumes and both memory measures, and BVMT-R learning slope was more strongly positively associated with hippocampal volumes than HVLT-R learning slope. Amnestic Mild Cognitive Impairment (aMCI) participants showed specific positive associations between BVMT-R performance and hippocampal volumes bilaterally. Additionally, analyses of the aMCI group showed trend-level evidence of material-specific lateralization, such that retention of verbal information was positively associated with left hippocampal volume, whereas learning curve and retention of non-verbal information was positively associated with right hippocampal volume.ConclusionsFindings support the link between episodic memory and hippocampal volumes in a memory clinic population. Non-verbal memory measures also may have higher diagnostic value, particularly in individuals at elevated risk for Alzheimer’s disease.

Retinal nerve fiber layer (RNFL) thickness, ganglion cell layer (GCL) thickness, and macular volume (MV) utilizing spectral domain optical coherence tomography (SD-OCT) were compared among patients with Alzheimer’s disease (AD) dementia, non-Alzheimer’s disease (non-AD) dementia, amnestic mild cognitive impairment (aMCI), Parkinson’s disease (PD), and age- and sex-matched controls in a cross-sectional cohort study. A total of 116 participants were diagnosed and evaluated (21 AD, 20 aMCI, 20 non-AD, 20 PD, and 34 controls) after comprehensive neurological, neuropsychology, and magnetic resonance imaging (MRI) volumetric evaluations. Retinal nerve fiber layer thickness, GCL thickness, and MV were measured. Analysis of variance models were used to compare groups on MRI volumetric measures, cognitive test results, and SD-OCT measures. Associations between SD-OCT measures and other measures were performed using mixed-effect models. Spectral domain optical coherence tomography analysis of retinal markers, including RNFL thickness, GCL thickness, and MV, did not differ between amnestic MCI, AD dementia, PD, non-AD, dementia, and age- and sex-matched controls in a well-characterized patient cohort.

Individuals with schizophrenia have relative deficits in cognition, although little is known regarding the course of such deficits across the lifespan and at various stages of the illness. Furthermore, the relationship between psychosis and cognition has not been adequately explored to this point. Prospective, longitudinal, multi-assessment studies of the same patients across time are rare in the field and provide a unique opportunity to examine long-term changes in cognition among individuals with schizophrenia. As part of The Chicago Follow-up Study, we prospectively assessed 244 psychiatric inpatients, including individuals with schizophrenia, other psychotic disorders, and non-psychotic depression. Assessments were conducted seven times (once at index hospitalization, and then 6 times subsequently over the next 20 years) to provide longitudinal data about cognition and symptoms, with a focus on two aspects of cognition: processing speed and the ability to access general knowledge. The Digit Symbol-Coding and Information subtests from the Wechsler Adult Intelligence scale were used to measure the two cognitive domains at each assessment. At all 7 assessments, individuals with schizophrenia performed more poorly than the other diagnostic groups on the two cognitive measures. However, following the acute phase (index hospitalization), individuals with schizophrenia demonstrated significant improvements in cognition and did not show evidence of cognitive decline over the remaining six assessments spanning 20 years. Our data support the presence of relative cognitive impairment in schizophrenia, as well as a pattern of stability in some cognitive areas following the acute phase. Additionally, we find evidence for an association between relative cognitive impairment and psychosis.The current research prospectively investigated the longitudinal course of two neurocognitive measures in individuals with schizophrenia and other mental disorders over a 20-year follow-up period. Cognitive deficits are now acknowledged to be one of the central aspects of the schizophrenia syndrome [1], and there is evidence of cognitive impairments among individuals with schizophrenia in a variety of domains [2][3][4]. Furthermore, cognitive deficits in individuals with schizophrenia have been identified prodromally during childhood, during the first episode of psychosis [5], and many years after the initial onset of illness [6]. However, despite the strides that have been made in characterizing the cognitive profile of schizophrenia at different stages of the illness, most studies have been crosssectional or have used relatively short follow-up intervals. Thus, the longitudinal course and trajectory of cognitive function in schizophrenia is not as well described.Corresponding Author: Aaron Bonner-Jackson, University of Illinois at Chicago, Department of Psychiatry, 912 S. Wood St., m/c 913, Chicago, IL 60612, aaronbonnerjackson@gmail.com, Telephone: (312) Fax: (312) 413-4915. Publisher's Disclaimer: This is a PDF file of an ...

Objective A subset of individuals with coronavirus disease 2019 (COVID-19) appears to develop persisting cognitive and medical symptoms. Research in the acute stages of illness, generally utilizing cognitive screening measures or case reports, suggests presence of deficits in attention and executive function. This observational study investigated cognitive functioning among individuals with persistent cognitive complaints about 5.5 months after COVID-19 infection. Methods Patients with polymerase chain reaction confirmed COVID-19 and persistent cognitive complaints underwent comprehensive in-person neuropsychological evaluations. Patients with prior neurological disorders were excluded. When diagnosed, 40% required hospitalization, 15% were in an intensive care unit, 10% needed mechanical ventilation, and 10% experienced delirium. Results This sample was predominately women (90%), White non-Hispanic (70%), with average education of 15 years. Mild cognitive deficits were seen on tests involving attention and processing speed or executive function. Seventy percent of patients were diagnosed with a mood disorder prior to COVID-19 infection. At the time of testing, 35%–40% endorsed moderate to severe mood symptoms and 85% noted significant fatigue as measured by the Fatigue Severity Scale. Conclusions The pattern of cognitive deficits, although mild, is consistent with prior research at the acute stage of the illness. These findings suggest that psychological factors and other persisting symptoms (e.g., sleep, fatigue) may play a significant role in subjective cognitive complaints in patients with persisting complaints post COVID-19 who did not require intensive treatment. These patients would likely benefit from resources to manage persisting or new mood symptoms and compensatory strategies for the cognitive inefficiencies they experience.

Healthy aging is associated with cognitive declines typically accompanied by increased task-related brain activity in comparison to younger counterparts. The Scaffolding Theory of Aging and Cognition (STAC) (Park and Reuter-Lorenz, 2009; Reuter-Lorenz and Park, 2014) posits that compensatory brain processes are responsible for maintaining normal cognitive performance in older adults, despite accumulation of aging-related neural damage. Cross-sectional studies indicate that cognitively intact elders at genetic risk for Alzheimer’s disease (AD) demonstrate patterns of increased brain activity compared to low risk elders, suggesting that compensation represents an early response to AD-associated pathology. Whether this compensatory response persists or declines with the onset of cognitive impairment can only be addressed using a longitudinal design. The current prospective, 5-year longitudinal study examined brain activation in APOE ε4 carriers (N=24) and non-carriers (N=21). All participants, ages 65–85 and cognitively intact at study entry, underwent task-activated fMRI, structural MRI, and neuropsychological assessments at baseline, 18, and 57 months. fMRI activation was measured in response to a semantic memory task requiring participants to discriminate famous from non-famous names. Results indicated that the trajectory of change in brain activation while performing this semantic memory task differed between APOE ε4 carriers and non-carriers. The APOE ε4 group exhibited greater activation than the Low Risk group at baseline, but they subsequently showed a progressive decline in activation during the follow-up periods with corresponding emergence of episodic memory loss and hippocampal atrophy. In contrast, the non-carriers demonstrated a gradual increase in activation over the 5-year period. Our results are consistent with the STAC model by demonstrating that compensation varies with the severity of underlying neural damage and can be exhausted with the onset of cognitive symptoms and increased structural brain pathology. Our fMRI results could not be attributed to changes in task performance, group differences in cerebral perfusion, or regional cortical atrophy.

Background Huntington disease (HD) is associated with decline in cognition and progressive morphological changes in brain structures. Cognitive reserve may represent a mechanism by which disease-related decline may be delayed or slowed. The current study examined the relationship between cognitive reserve and longitudinal change in cognitive functioning and brain volumes among prodromal (gene expansion-positive) HD individuals. Methods Participants were genetically-confirmed individuals with prodromal HD enrolled in the PREDICT-HD study. Cognitive reserve was computed as the composite of performance on a lexical task estimating premorbid intellectual level, occupational status, and years of education. Linear mixed effects regression (LMER) was used to examine longitudinal changes on 4 cognitive measures and 3 brain volumes over approximately 6 years. Results Higher cognitive reserve was significantly associated with a slower rate of change on one cognitive measure (Trail Making Test, Part B) and slower rate of volume loss in two brain structures (caudate, putamen) for those estimated to be closest to motor disease onset. This relationship was not observed among those estimated to be further from motor disease onset. Conclusions Our findings demonstrate a relationship between cognitive reserve and both a measure of executive functioning and integrity of certain brain structures in prodromal HD individuals.