Early Cognitive Changes Research Articles

Impaired memory following predatory stress in mice is improved by fluoxetine

The first purpose of the present study was to investigate possible effects of predatory stress (i.e., 5-min cat exposure) on short-term learning abilities in Swiss mice using the object recognition test (ORT). The second aim was to evaluate the effects of anxiolytics (i.e., diazepam and fluoxetine) on learning/memory abilities in the ORT following predatory stress. Results showed that predatory exposure impaired learning and produced amnesia of acquired information or impairment to retrieve learned information (48 and 96 h poststressor). The learning impairment in the ORT in stressed mice was restored by acute fluoxetine treatment, but not by diazepam that instead affected learning in nonstressed animals. Taken together, these findings indicate that this animal model of exposure of mice to unavoidable predatory stimuli produces early cognitive changes analogous to those seen in patients with acute stress disorder (ASD).

Apolipoprotein E ε4 affects new learning in cognitively normal individuals at risk for Alzheimer’s disease

The Apolipoprotein E (APOE) ε4 allele is an important risk factor for Alzheimer’s disease (AD). Given the interest in early identification of at-risk individuals, we examined memory decline as a function of APOE status and age in cognitively intact participants aged 48–77 years old (yo). Participants were grouped by age (<60 versus ≥60) and APOE (ε4+/−). Longitudinal analysis of several components of memory over a 2-year interval showed a significant Age-by-APOE interaction reflecting a decline in new learning for the ≥60 ε4+ group only. Among ε4+, 76% of the ≥60 participants showed a decline versus 32% of the <60, but the amount of decline in new learning over the 2-year interval within the ≥60 group was not further influenced by age. That is, the size of the 2-year change was the same for 60 and 70 yo participants. This suggests that longitudinal study of new learning is a sensitive measure for detecting early cognitive changes in at-risk individuals that precede the symptomatic onset of mild cognitive impairment and AD.

Neuropsychological features of mild cognitive impairment and preclinical Alzheimer's disease

Recent research has identified a transitional state between the cognitive changes of normal aging and Alzheimer's disease (AD), known as mild cognitive impairment (MCI). MCI patients experience memory loss to a greater extent than one would expect for age, yet they do not meet currently accepted criteria for clinically probable AD. An issue currently under investigation is whether MCI represents the preclinical stages of AD or a distinct and static cognitive aetiology. In an attempt to address this issue, the present investigations are adopting a convergent approach to the detection of preclinical AD, where multiple risk factors are considered when making a diagnosis. Currently, one of the most important tools when assessing early cognitive changes is neuropsychological evaluation. MCI subjects typically record neuropsychological performance between that of healthy older individuals and demented patients. Tests assessing new learning, delayed recall and attention/executive function seem to provide valuable information for screening and diagnosis of MCI and early AD if interpreted properly. Recommendations concerning methodological issues and the early management of neuropsychological MCI studies were made.

Early cognitive changes and differential diagnosis in dementia

Early cognitive changes and differential diagnosis in dementia

Relationship between Hippocampal Atrophy and Cognitive Dysfunction in Early Alzheimer‐type Dementia

Abstract Background: We assessed the relationship between early cognitive dysfunction and morphologic changes in the brain, especially hippocampal atrophy, on MR images in Alzheimer‐type dementia (AID) patients to establish a technique for making an early clinical diagnosis of AID. Methods: The subjects of this study were 82 individuals who visited Kawase Neurology Clinic. They consisted of 41 ATD patients and 41 elderly individuals without dementia who visited the clinic for a neurological checkup or because of vertigo or numbness as age‐matched controls. As an index for hippocampal atrophy, the hippocampal‐intracranial ratio (HIR) was calculated. Discriminant analysis was performed using HIR results and the correct answer rate for recall and calculation items in Mini‐Mental State Examination (MMSE). Results: The mean ratio was significantly lower in the ATD patients than in the controls. This supports our previous results. The results of discriminant analysis with Mahalanobis generalized distance in the 41 controls and 22 ATD patients who scored 15 or higher. The sensitivity and specificity of HIR combined with the correct answer rate for recall and calculation items in MMSE were 95.5% and 95.1%, respectively, with an overall accuracy of 95.2%. Conclusion: HIR combined with the correct answer rate for recall and calculation items in MMSE allows for an early diagnosis of ATD.

A reply

We appreciate the interest of Dr Alston in our review article on jugular bulb oximetry during cardiac surgery [1]. We agree with him that bench oximetry, not fibreoptic catheters, is the gold standard for the measurement of jugular bulb oxygen saturation (Sjo2) during cardiopulmonary bypass (CPB). Dr Alston provides a perfectly valid explanation of why Sjo2 less than 50% occurs during cardiopulmonary bypass and why, postoperatively, hyperventilation leads to reduced arterial carbon dioxide tension (Paco2), cerebral vasoconstriction, decreased cerebral perfusion and hence increase in oxygen extraction and reduced Sjo2. We recently studied the effect of Paco2 on Sjo2[2], but found that it explains only 34% of the variance of Sjo2 during warm CPB. Recently, Robson and colleagues found that cognitive dysfunction at 3 months after CPB was not related to jugular bulb desaturation (Sjo2 < 50%) during or after CPB [3]. In their study, the authors did not report the early cognitive changes in the first week after CPB or its relation to Sjo2, which was reported by Croughwell et al. [4]. It would be very interesting to confirm this finding because it seems that jugular bulb desaturation may affect only short-term cognitive dysfunction. Low Sjo2 is a symptom of reduced oxygen availability to the brain and if values < 50% do not lead to long-term cerebral damage, we must presume that the brain can still function under this condition. However, there must be some lower limit of Sjo2 (20%, 30%, 40%?) below which cerebral damage will occur. Another factor might be cerebral damage arising from embolism, which would be minimised by reduced cerebral perfusion. We have tried to explain in our review article that Sjo2 does reflect global cerebral oxygenation but does not detect regional cerebral oxygenation. This was confirmed in our recent paper [5] where we found that Sjo2 did not reflect impairment of regional cerebral oxygenation detected by near-infrared spectroscopy (NIRS). Therefore, if brain injury is due to regional ischaemia, it may or may not be reflected by Sjo2. Thus, in attempting to optimise cerebral oxygenation during CPB, it is important to determine whether the aim should be to maintain good oxygenation of the brain or to minimise cerebral perfusion and hence the risk of embolism (while still maintaining adequate oxygenation – whatever this may be).

Timing and specificity of the cognitive changes induced by interleukin-2 and interferon-alpha treatments in cancer patients.

Neuropsychological changes develop in patients treated by cytokine immunotherapy with interleukin-2 (IL-2) and interferon-alpha (IFN-alpha). However, the time course of appearance of these effects remains unclear, and their precise nature is still incompletely characterized. The objective of this study was to assess and characterize the early cognitive changes induced by IL-2 and IFN-alpha in cancer patients at the end of the first week of treatment and to investigate the subsequent evolution of these changes. The study was conducted in 47 cancer patients who received subcutaneous IL-2, administered alone (N = 17) or with IFN-alpha (N = 7), or IFN-alpha alone, administered subcutaneously at low doses (N = 7) or intravenously at high doses (N = 16). An automated battery of neuropsychological tests (Cambridge Neuropsychological Test Automated Battery) was used to measure reaction time, spatial working memory, and planning tasks. Cognitive tests were performed before treatment (day 1) and after 5 days (day 5) and 1 month of treatment. On day 5, patients treated with IL-2 alone had impaired spatial working memory and lower accuracy of planning abilities. In contrast, patients treated with IFN-alpha did not show any impairment in performance accuracy in these tasks but showed longer latencies in the test of reaction time. Most of these early alterations persisted at the end of the first month of treatment without any obvious sign of worsening. These findings suggest the existence of early differential neuropsychological changes in patients treated with IL-2 and IFN-alpha.

Neuropsychological Profile of Patients with Primary Systemic Hypertension

Arterial hypertension represents a risk factor for cerebrovascular disease. It has been hypothesized that chronic hypertension may eventually result in small subcortical infarcts associated with some cognitive impairments.One hundred fourteen patients with primary systemic hypertension (PSH) and 114 matched subjects were selected. PSH patients were further divided in four groups depending upon the hypertension severity. In addition 10 the medical and laboratory exams, a neuropsychological evaluation was administered. The NEUROPSI neuropsychological test battery was used.An association between level of hypertension and cognitive impairment was observed. Most significant differences were observed in the following domains: Reading, executive functioning, constructional, and memory-recall. No differences were observed in orientation, memory-recognition, and language. Some neuropsychological functions appeared impaired even in the PSH group with the least risk factors.Cognitive evaluation may be important in cases of PSH not only to determine early subtle cognitive changes, but also for follow-up purposes, and to assess the efficacy of different therapeutic procedures.

Homeless people preserved former identities, devalued current identities, and envisioned a non-homeless future

<h3>Background</h3> Dementia is common in Parkinson’s disease (PD) but measures that track cognitive change in PD are lacking. Brain tissue iron accumulates with age and co-localises with pathological proteins linked...

A prospective study of cognitive function and onset of dementia in cognitively healthy elders.

To examine the earliest cognitive changes associated with the onset of dementia as well as changes associated with normal aging. Longitudinal evaluation of participants with annual clinical and psychometric examinations for up to 15 1/2 years. Elderly volunteers (n = 82) enrolled with a Clinical Dementia Rating of 0 (cognitively intact) in longitudinal studies. None. Clinical Dementia Rating and results of a 1 1/2-hour psychometric battery. As estimated with survival analysis, 40% of participants had a Clinical Dementia Rating greater than 0 (cognitive decline) within 12 years of enrollment; 59% of these were judged to have dementia of the Alzheimer type or incipient dementia. Participants with poorer performance on psychometric testing at enrollment were at higher risk for cognitive decline subsequently. The rate of change in psychometric performance before clinically detectable cognitive change occurred was not significantly different between those who eventually developed dementia and those who remained stable, except for performance on the Logical Memory subtest of the Wechsler Memory Scale. When subtle cognitive decline was clinically detected, however, an abrupt deterioration in performance on independently administered psychometric tests was observed. Cognitively healthy elderly people maintain stable cognitive performance when measured longitudinally by both careful clinical evaluation and repeated psychometric testing. This stability is maintained unless and until they develop a dementing illness, at which time a sharp decline in performance is observed.

Assessment of Aids-related cognitive changes: Recommendations of the NIMH workshop on neuropsychological assessment approaches

This article presents an extended (7-9 hours) and a brief (1-2 hours) battery designed to evaluate early cognitive changes associated with seropositive, asymptomatic persons. The battery was recommended by an NIMH Workgroup which was guided by 10 principles in its development. The domains assessed by the battery are: (1) Indicators of Premorbid Intelligence; (2) Attention; (3) Speed of Processing; (4) Memory; (5) Abstraction; (6) Language; (7) Visuoperception; (8) Constructional Abilities; (9) Motor Abilities; and (10) Psychiatric Assessment. Although the battery assesses a wide range of psychological functioning, specific emphasis has been placed on divided and sustained attention as well as speed of processing and retrieval from working and long-term memory. Descriptions of both the traditional clinical tests and tasks used in cognitive psychology are provided. Although the Workgroup strongly recommends the use of the extended battery in order to ensure the most sensitivity, it recognizes that there may be situations in which this is not possible. In order to increase the likelihood that neuropsychological tests will identify neurologically affected CDC Stage II and III seropositive individuals, the Workshop recommends that each patient's protocol be rated by two trained neuropsychologists using the same clinical criteria. The Workgroup also recommends that a concerted effort be made to incorporate data from the extended and the brief batteries in some central data bank.

Slowed information processing as an early cognitive change associated with HIV infection.

Slowed information processing as an early cognitive change associated with HIV infection.

Slowed information processing as an early cognitive change associated with HIV infection.

Slowed information processing as an early cognitive change associated with HIV infection.