Profiles of cognitive decline in Alzheimer disease

Most recent studies have used only two observations to estimate the rate of cognitive decline in patients with Alzheimer disease (AD); few have data taken from more than a 2-year period; and none report on autopsy-verified cases. Repeated observations over the complete course of the disease are necessary to quantitatively evaluate hypotheses such as the triphasic linear model of Brooks et al. (1993). The goal of this study is to compare the triphasic linear and quadratic models of decline in a group of 12 AD patients confirmed at autopsy with a group of age- and sex-matched normal control subjects. Both groups were taken from the University of Western Ontario Dementia Study, and the Extended Scale for Dementia was used as the outcome measure. The squared multiple correlation as a measure of goodness of fit suggested the superiority of the more parsimonious quadratic model over the triphasic linear model. Quantitative models more accurately reflect the profiles of change in AD and may prove more sensitive in measuring the effects of drugs on these patterns.

Connexin43 null mutation increases infarct size after stroke

Glial-neuronal interactions have been implicated in both normal information processing and neuroprotection. One pathway of cellular interactions involves gap junctional intercellular communication (GJIC). In astrocytes, gap junctions are composed primarily of the channel protein connexin43 (Cx43) and provide a substrate for formation of a functional syncytium implicated in the spatial buffering capacity of astrocytes. To study the function of gap junctions in the brain, we used heterozygous Cx43 null mice, which exhibit reduced Cx43 expression. Western blot analysis showed a reduction in the level of Cx43 protein and GJIC in astrocytes cultured from heterozygote mice. The level of Cx43 is reduced in the adult heterozygote cerebrum to 40% of that present in the wild-type. To assess the effect of reduced Cx43 and GJIC on neuroprotection, we examined brain infarct volume in wild-type and heterozygote mice after focal ischemia. In our model of focal stroke, the middle cerebral artery was occluded at two points, above and below the rhinal fissure. Four days after surgery, mice were killed, the brains were sectioned and analyzed. Cx43 heterozygous null mice exhibited a significantly larger infarct volume compared with wild-type (14.4 +/- 1.4 mm(3) vs. 7.7 +/- 0.82 mm(3), P < 0.002). These results suggest that augmentation of GJIC in astrocytes may contribute to neuroprotection after ischemic injury.

Internal borderzone infarction: a marker for severe stenosis in patients with symptomatic internal carotid artery disease. For the North American Symptomatic Carotid Endarterectomy (NASCET) Group

BACKGROUND AND PURPOSE

Among subcortical infarctions, internal borderzone infarcts (IBI) are considered to be separate entities from perforating artery infarcts (PAI). The purpose of the present study is to examine the relationship between the presence of IBI and the degree of angiographically defined internal carotid artery (ICA) stenosis in symptomatic patients.

METHODS

A review of 1253 brain CTs from patients recruited by the North American Symptomatic Carotid Endarterectomy Trial was performed, using templates for the identification of subcortical and cortical vascular territories.

RESULTS

A total of 413 patients had visible ischemic lesions on the side ipsilateral to their symptomatic ICA. Of these, 138 had PAI, 108 had IBI, 122 had cortical infarcts, and 45 had a combination of different lesions. Mean (+/-SD) lesion diameter was larger for IBI (11.0+/-5.9 mm) than for PAI (7.1+/-4.7 mm) (P<0.001 for comparing 2 means). IBI was associated with higher degrees of ICA stenosis (P<0. 001). Sixty-three percent of the patients with IBI had severe (70% to 99%) ICA stenosis compared with 42% of patients with PAI; 18% of the IBI patients had stenosis of 90% or more compared with 8% of the patients with PAI. Multiple logistic regression did not identify any patient characteristics as confounders.

CONCLUSIONS

Among subcortical infarctions, IBI are associated with higher degrees of ICA stenosis in symptomatic patients. Differentiating between internal borderzone and perforating artery infarcts is important, because each may arise from different mechanisms, namely, carotid disease and small-vessel disease, respectively.

Vascular Cognitive Impairment

Although vascular dementia remains the only form of dementia that is preventable, available treatment is limited to the primary and secondary prevention of cerebrovascular disease. Strokes are highly responsive to different forms of prevention and treatment. The effectiveness of the same measures in the prevention of vascular dementia remains unclear, however, owing mainly to the lack of agreement on the definition and management of cognitive impairment. The successful treatment of "vascular dementia" involves the recognition of this term as obsolete, for it falsely implies that the underlying cognitive impairment has an unknown degenerative cause, is progressive, and responds neither to currently available preventive measures nor to treatments. Although dementia resulting from multiple strokes can be a terminal manifestation of this form of cognitive impairment, most patients have treatable cerebrovascular disease. A rational therapeutic approach to the treatment of this cognitive syndrome necessitates an understanding of its broad clinical spectrum and the diverse causes that may be responsive to currently available treatments, from the clinical asymptomatic "brain-at-risk" stage to full-blown dementia.

The cognitive syndrome of vascular dementia: implications for clinical trials

Dementia is common among patients with cerebrovascular disease, particularly in a setting of one or more clinically evident strokes. Prior cohort and case studies have suggested that the cognitive syndrome of vascular dementia is characterized by predominant executive dysfunction, in contrast to the deficits in memory and language function that are typical of patients with Alzheimer disease. The course of cognitive decline may also differ between those dementia subtypes, with many, but not all, patients with vascular dementia exhibiting a stepwise course of decline caused by recurrent stroke and most patients with Alzheimer disease exhibiting a gradually progressive course of decline. The findings of prior studies of the cognitive syndrome of vascular dementia must be interpreted with caution, however, because of (1) possible inaccuracies in the determination of the dementia subtype and the loss of precision that might result from pooling heterogeneous subgroups of patients with vascular dementia, (2) difficulties inherent in identifying a pattern of strengths and weaknesses in patients who are required to have memory impairment and other deficits to meet operationalized criteria for dementia, and (3) the use of limited test batteries whose psychometric properties are incompletely understood. Specific questions that should be addressed by future studies are discussed.

The North American Symptomatic Carotid Endarterectomy Trial : surgical results in 1415 patients

BACKGROUND AND PURPOSE

This study reports the surgical results in those patients who underwent carotid endarterectomy in the North American Symptomatic Carotid Endarterectomy Trial (NASCET).

METHODS

The rates of perioperative stroke and death at 30 days and the final assessment of stroke severity at 90 days were calculated. Regression modeling was used to identify variables that increased or decreased perioperative risk. Nonoutcome surgical complications were summarized. The durability of carotid endarterectomy was examined.

RESULTS

In 1415 patients there were 92 perioperative outcome events, for an overall rate of 6.5%. At 30 days the results were as follows: death, 1.1%; disabling stroke, 1.8%; and nondisabling stroke, 3.7%. At 90 days, because of improvement in the neurological status of patients judged to have been disabled at 30 days, the results were as follows: death, 1.1%; disabling stroke, 0.9%; and nondisabling stroke, 4.5%. Thirty events occurred intraoperatively; 62 were delayed. Most strokes resulted from thromboembolism. Five baseline variables were predictive of increased surgical risk: hemispheric versus retinal transient ischemic attack as the qualifying event, left-sided procedure, contralateral carotid occlusion, ipsilateral ischemic lesion on CT scan, and irregular or ulcerated ipsilateral plaque. History of coronary artery disease with prior cardiac procedure was associated with reduced risk. The risk of perioperative wound complications was 9.3%, and that of cranial nerve injuries was 8.6%; most were of mild severity. At 8 years, the risk of disabling ipsilateral stroke was 5.7%, and that of any ipsilateral stroke was 17.1%.

CONCLUSIONS

The overall rate of perioperative stroke and death was 6.5%, but the rate of permanently disabling stroke and death was only 2.0%. Other surgical complications were rarely clinically important. Carotid endarterectomy is a durable procedure.

Benefit of carotid endarterectomy in patients with symptomatic moderate or severe stenosis. North American Symptomatic Carotid Endarterectomy Trial Collaborators

BACKGROUND

Previous studies have shown that carotid endarterectomy in patients with symptomatic severe carotid stenosis (defined as stenosis of 70 to 99 percent of the luminal diameter) is beneficial up to two years after the procedure. In this clinical trial, we assessed the benefit of carotid endarterectomy in patients with symptomatic moderate stenosis, defined as stenosis of less than 70 percent. We also studied the durability of the benefit of endarterectomy in patients with severe stenosis over eight years of follow-up.

METHODS

Patients who had moderate carotid stenosis and transient ischemic attacks or nondisabling strokes on the same side as the stenosis (ipsilateral) within 180 days before study entry were stratified according to the degree of stenosis (50 to 69 percent or <50 percent) and randomly assigned either to undergo carotid endarterectomy (1108 patients) or to receive medical care alone (1118 patients). The average follow-up was five years, and complete data on outcome events were available for 99.7 percent of the patients. The primary outcome event was any fatal or nonfatal stroke ipsilateral to the stenosis for which the patient underwent randomization.

RESULTS

Among patients with stenosis of 50 to 69 percent, the five-year rate of any ipsilateral stroke (failure rate) was 15.7 percent among patients treated surgically and 22.2 percent among those treated medically (P=0.045); to prevent one ipsilateral stroke during the five-year period, 15 patients would have to be treated with carotid endarterectomy. Among patients with less than 50 percent stenosis, the failure rate was not significantly lower in the group treated with endarterectomy (14.9 percent) than in the medically treated group (18.7 percent, P=0.16). Among the patients with severe stenosis who underwent endarterectomy, the 30-day rate of death or disabling ipsilateral stroke persisting at 90 days was 2.1 percent; this rate increased to only 6.7 percent at 8 years. Benefit was greatest among men, patients with recent stroke as the qualifying event, and patients with hemispheric symptoms.

CONCLUSIONS

Endarterectomy in patients with symptomatic moderate carotid stenosis of 50 to 69 percent yielded only a moderate reduction in the risk of stroke. Decisions about treatment for patients in this category must take into account recognized risk factors, and exceptional surgical skill is obligatory if carotid endarterectomy is to be performed. Patients with stenosis of less than 50 percent did not benefit from surgery. Patients with severe stenosis (> or =70 percent) had a durable benefit from endarterectomy at eight years of follow-up.

Meta-analysis of the Hachinski Ischemic Score in pathologically verified dementias

Our objectives were to investigate the utility of the Hachinski Ischemic Score (HIS) in differentiating patients with pathologically verified Alzheimer's disease (AD), multi-infarct dementia (MID), and "mixed" (AD plus cerebrovascular disease) dementia, and to identify the specific items of the HIS that best discriminate those dementia subtypes. Investigators from six sites participated in a meta-analysis by contributing original clinical data, HIS, and pathologic diagnoses on 312 patients with dementia (AD, 191; MID, 80; and mixed, 41). Sensitivity and specificity of the HIS were calculated based on varied cutoffs using receiver-operator characteristic curves. Logistic regression analyses were performed to compare each pair of diagnostic groups to obtain the odds ratio (OR) for each HIS item. The mean HIS (+/- SD) was 5.4 +/- 4.5 and differed significantly among the groups (AD, 3.1 +/- 2.5; MID, 10.5 +/- 4.1; mixed, 7.7 +/- 4.3). Receiver-operator characteristic curves showed that the best cutoff was < or = 4 for AD and > or = 7 for MID, as originally proposed, with a sensitivity of 89.0% and a specificity of 89.3%. For the comparison of MID versus mixed the sensitivity was 93.1% and the specificity was 17.2%, whereas for AD versus mixed the sensitivity was 83.8% and the specificity was 29.4%. HIS items distinguishing MID from AD were stepwise deterioration (OR, 6.06), fluctuating course (OR, 7.60), hypertension (OR, 4.30), history of stroke (OR, 4.30), and focal neurologic symptoms (OR, 4.40). Only stepwise deterioration (OR, 3.97) and emotional incontinence (OR, 3.39) distinguished MID from mixed, and only fluctuating course (OR, 0.20) and history of stroke (OR, 0.08) distinguished AD from mixed. Our findings suggest that the HIS performed well in the differentiation between AD and MID, the purpose for which it was originally designed, but that the clinical diagnosis of mixed dementia remains difficult. Further prospective studies of the HIS should include additional clinical and neuroimaging variables to permit objective refinement of the scale and improve its ability to identify patients with mixed dementia.

Comparative evolution of Alzheimer disease, vascular dementia, and mixed dementia

OBJECTIVE

To compare the evolution of Alzheimer disease (AD), vascular dementia (VaD), and mixed dementia by cognitive domain.

SETTING

The University of Western Ontario Dementia Study, which is a registry of cases of dementia seen for secondary and tertiary assessment in a university memory disorders clinica with extensive follow-up data and histopathological confirmation of clinical diagnoses.

PATIENTS

One hundred twenty-nine patients with definite or probable AD, 12 patients with definite or probable VaD, and 36 patients with definite or probable mixed dementia.

METHODS

Patients were grouped as having an early, moderate, or advanced stage of disease according to the extended scale for dementia (ESD). The ESD was subdivided into cognitive domains, and the domain scores were compared for each stage of disease by diagnostic category with the use of a 2-way analysis of variance with repeated measures.

RESULTS

As expected, the scores in all domains decreased significantly with increasing severity. There was a significant difference in the decline in memory among the diagnostic groups (P = .02) that was mostly attributable to the difference between AD and mixed dementia (P = .03), with the difference between AD and VaD only approaching significance (P = .06). There was a similar finding for praxis. The interaction between diagnosis (AD and VaD) and severity was significant only for memory (P = .02), showing a less severe memory deficit at onset but a proportionately more rapid progression in VaD and arithmetic ability (AD and mixed dementia [P = .03]).

CONCLUSIONS

Alzheimer disease, VaD, and mixed dementia evolve similarly as assessed using cognitive domains obtained by subdivision of the ESD in a patient population derived from a memory clinic and by analyzing VaD as a single entity. Only memory impairment evolves differently between AD and VaD, with this depending on the severity. Memory is more severely impaired in the early stage of AD; however, with increasing severity of dementia, memory impairment in VaD accelerates and catches up with AD at the level of moderate impairment. The differences between AD and mixed dementia are greater than those between mixed dementia and VaD, suggesting an important role for the ischemic component of mixed dementia. Simple neuropsychological tools (eg, the ESD) may be incapable of distinguishing between AD and VaD, and more focused instruments may be required. Inherent bias in case selection may prevent extrapolation of these results to VaD in general, but the neuropsychological criteria for VaD may need to vary, depending on the severity.

Cardiovascular response to stress after middle cerebral artery occlusion in rats

Previously, we have shown cardiovascular and autonomic disturbances in male Wistar rats following middle cerebral artery occlusion (MCAO). Using this model, neurochemical changes, that were maximal at 3-5 days and subsiding by day 10, were observed unilaterally in the insular cortex and amygdala. The amygdalar neurochemical changes may be related to the stroke-induced cardiovascular disturbances, since the amygdala is critical in mediating the cardiovascular responses to stress. We examined the cardiovascular responses to intermittent and continuous noise and air-jet stimulation in male Wistar rats on days 2-10 after right-sided MCAO or sham MCAO. Compared to the sham MCAO rats, intermittent noise elicited significant tachycardiac responses on days 5 and 7 after stroke. Air-jet stimulation also elicited a significant tachycardic response on day 5, whereas continuous noise produced significant tachycardiac and pressor responses at days 5 and 7, respectively, in the MCAO rats compared to the control rats. Analyses on the heart rate variability using fast Fourier transformation revealed significant increases in the normalized mid-frequency spectral power on day 7 for intermittent noise and air-jet stimulation, suggesting increases in the sympathetic activity. These results indicate a time-course of exaggerated cardiovascular responses to stress and suggest a state of susceptibility to cardiac perturbations in rats following stroke.

[Management of patients with acute phase of stroke]

At the moment, the only treatment of proven efficacy in reducing mortality and improving evolution of patients with ischemic stroke is management of these patients by specialized personal, in specific units (stroke units) to provide an adequate and early program of general care, control of complications and rehabilitation. On the basis of physiopathological knowledge, other specific therapeutical agents are being investigated, following essentially two ways: 1) to provide early reperfussion of ischemic tissue by an adequate control of hemodinamics, use of antithrombotic agents and/or use of trombolytic agents, and 2) to inhibit the ischemia-reperfussion injury mediators (acidosis, cytoplasmic overload of calcium and excess of free radicals) using cytoprotectors. Probably, optimum results will be obtained only with an adequate combination of both reperfussion and cytoprotection.

Prognosis for patients following a transient ischemic attack with and without a cerebral infarction on brain CT. North American Symptomatic Carotid Endarterectomy Trial (NASCET) Group

BACKGROUND

Although cerebral infarctions are commonly observed on brain CTs of patients with TIAs, their prognostic importance is unknown.

METHOD

The association between appropriately sited brain infarctions (ie, lesions located in the anterior circulation of the brain and ipsilateral to the symptomatic stenosed carotid artery) visualized on CT and the risk of subsequent stroke was assessed by Cox proportional hazards regression in 164 patients presenting with TIA (and no history of previous stroke) and severe angiographically defined carotid stenosis (70 to 99%) from the North American Symptomatic Carotid Endarterectomy Trial.

RESULTS

Patients with a TIA and CT-verified brain lesions were older and were more likely to have higher degrees of carotid stenosis and carotid plaque ulceration, a longer duration of symptoms, and a history of hypertension. With regard to prognosis, after adjusting for all known risk factors (patient characteristics) in a regression analysis, the presence of ischemic lesions observed on CT was not associated with an increased risk of ipsilateral stroke at 2 years (adjusted hazard ratio = 1.00; 95% CI: 0.39 to 2.58; p value = 0.99).

CONCLUSION

Considered in combination with other patient characteristics, the mere presence of an appropriately sited cerebral infarction on CT does not alter the prognosis (risk of ipsilateral strokes) of severely stenosed patients with TIA. Therefore, there is no clinical rationale in differentiating patients with TIA on the basis of CT findings alone.

The risk of stroke in patients with first-ever retinal vs hemispheric transient ischemic attacks and high-grade carotid stenosis. North American Symptomatic Carotid Endarterectomy Trial

BACKGROUND

The prognosis of amaurosis fugax has been considered to be favorable compared with that of hemispheric transient ischemic attacks. However, this has remained uncertain for patients with significant carotid stenosis as the assessment of progression of the disease has been confounded when patients undergo carotid endarterectomy. In the North American Symptomatic Carotid Endarterectomy Trial, patients with high-grade (70% to 99%) carotid stenosis were randomized to receive either medical or surgical treatment, thus making an unconfounded analysis possible.

METHOD

We identified 129 medically treated patients with high-grade carotid stenosis who had their first-ever transient ischemic attack as the entry event into the trial. Fifty-nine patients with retinal transient ischemic attacks (RTIAs) were compared with 70 patients with hemispheric transient ischemic attacks (HTIAs).

RESULTS

Patients with HTIAs were older, with a higher prevalence of most risk factors for stroke. Average time of delay from the onset of transient ischemic attacks to medical treatment was longer for patients with RTIAs than for patients with HTIAs (48.5 vs 15.2 days). Kaplan-Meier estimates of the risk of ipsilateral stroke at 2 years were 16.6% +/- 5.6% for patients with RTIAs and 43.5% +/- 6.7% for patients with HTIAs (P = .002 for the difference in risk between RTIAs and HTIAs). From corresponding Cox's proportional hazards regression analyses, the risk of ipsilateral stroke ranged from 11.2% to 28.9% for patients with RTIAs and from 37.4% to 96.3% for patients with HTIAs across stenoses, spanning 75% to 95%. Overall, the relative risk of ipsilateral stroke (HTIAs compared with RTIAs) was 3.23 (95% confidence interval, 1.47 to 7.12), regardless of the degree of high-grade stenosis.

CONCLUSION

To our knowledge, this study is the first report on the expected outcome for medically treated patients with high-grade (70% to 99%) carotid stenosis in whom the first-ever event was either an RTIA or HTIA. The presence of RTIAs carries a considerable risk of ipsilateral strokes, particularly at higher degrees of stenosis. However, in comparison with HTIAs, patients with RTIAs still have a better prognosis.

Patterns of deterioration in senile dementia of the Alzheimer type

OBJECTIVE

To determine rates of decline in Alzheimer's disease.

DESIGN

A longitudinal review of patients diagnosed as having dementia during life, tested serially with the Extended Scale for Dementia, and confirmed by autopsy as having Alzheimer's disease.

SUBJECTS AND SETTING

Twenty-nine dead patients with Alzheimer's disease from the participants in the University of Western Ontario Dementia Study Project, confirmed at autopsy as having Alzheimer's disease.

METHODS

Analysis of the Extended Scale for Dementia data according to a trilinear model.

FINDINGS

In the middle phase of the trilinear model, there was a mean annual change of 13% (range, 2.5% to 51.7%).

CONCLUSIONS

It is likely that the common method of averaging a group of different individual scores from the initial and middle phases of observation of Alzheimer's disease collapses together individuals at different stages of the disorder, some of whom are in the initial plateau phase and whose conditions are not declining rapidly. The trilinear model of decline avoids this difficulty and the present study provides postmortem confirmed figures on rate of change.

Lack of relationship between leukoaraiosis and carotid artery disease. The North American Symptomatic Carotid Endarterectomy Trial

OBJECTIVE

Leukoaraiosis (LA) (white matter changes) is frequently observed on computed tomographic scans of the brain of elderly patients at risk of stroke. A localized vascular-ischemic cause has been suggested for its underlying mechanism. Our aim was to assess whether high-grade carotid stenosis is associated with LA.

DESIGN/SETTING

Patients enrolled in the North American Symptomatic Carotid Endareterectomy Trial (also known as NASCET) were evaluated for LA using a recently proposed grading scale. Ordinal regression analysis was used to assess the association between the severity of carotid artery stenosis and the extent of LA observed on computed tomographic scans. The patients' brain hemisphere was selected as the unit of analysis.

RESULTS

Of the 2394 brain hemispheres contributed to the analyses, 352 (14.7%) had signs of LA. After controlling for known stroke risk factors in the ordinal regression analysis, only the history of stroke and increasing age were significantly related to LA. Severity of stenosis was observed to be unrelated (odds ratio [severe vs mild stenosis] = 1.08; 95% confidence interval, 0.73-1.62; P = .952) as were a history of hypertension and a history of myocardial infarction.

CONCLUSION

Leukoaraiosis is not associated with severe carotid artery stenosis.

The importance of family history in cerebrovascular disease

BACKGROUND AND PURPOSE

The role of genetics in cerebrovascular disease remains controversial. The purpose of this study was to assess the influence of family history on atherothrombotic infarction or transient ischemic attack.

METHODS

Ninety patients with stroke or transient ischemic attack and 90 age- and sex-matched community control subjects were studied prospectively. Medical and family histories were obtained from all subjects, and a complete physical examination was performed.

RESULTS

Eighty-five patients and 86 control subjects knew their family history for ischemic heart disease and stroke. A positive history for ischemic heart disease was present in 62 (73%) of the patients and 46 (53%) of the control subjects (P = .019), and a positive family history for stroke was present in 38 (47%) of the patients and 21 (24%) of the control subjects (P = .014).

CONCLUSIONS

Although a positive vascular family history was not an independent risk factor in a multivariate analysis, it was an excellent marker of the presence of other established vascular risk factors. Personal histories of ischemic heart disease, hypertension, and hyperlipidemia were found to be significant independent risk factors for stroke.

Angiographic detection of carotid plaque ulceration. Comparison with surgical observations in a multicenter study. North American Symptomatic Carotid Endarterectomy Trial

BACKGROUND AND PURPOSE

Carotid plaque ulceration is used as one of the determinants in deciding which patients should be submitted to carotid endarterectomy. Uncertainties about its importance persist. Its detection by angiography is an important consideration.

METHODS

The detection of ulceration by angiography was compared with observations during endarterectomy in the first 500 patients recruited into the North American Symptomatic Carotid Endarterectomy Trial. This represents the first multicenter compilation of data on this subject and the largest series of patients with both arteriographic and direct surgical observation.

RESULTS

Sensitivity and specificity of detecting ulcerated plaques were 45.9% and 74.1%, respectively. The positive predictive value of identifying an ulcer was 71.8%. These results remained unchanged with differing degrees of carotid stenosis and were confirmed by analyses based on receiver operating characteristic (ROC) methodology. The area under the ROC curve (Az) was estimated to be 0.61 (95% confidence interval, 0.55 to 0.67).

CONCLUSIONS

These observations from a multicenter study confirm that little agreement exists between angiography and surgical observation in detecting carotid plaque ulceration.

Electroencephalography as an aid in the exclusion of Alzheimer's disease

OBJECTIVE

To determine the usefulness or otherwise of the awake electroencephalogram (EEG) in the diagnosis of Alzheimer's disease (AD).

DESIGN

Prospective collection of one or more awake EEGs in patients diagnosed as having AD or mixed AD and multi-infarct dementia according to current systematic criteria with analysis of those cases confirmed by postmortem examination. Systematized blind interpretation of EEGs.

SETTING

Tertiary care practice with both ambulatory and hospitalized patients, ie, neurological department in general hospital and psychogeriatric unit in psychiatric hospital.

PATIENTS

A series of 86 subjects with AD and 17 with mixed AD and multi-infarct dementia being those members of a consecutive series on whom postmortem information was available. Awake EEGs in 56 age- and sex-matched control subjects.

RESULTS

Seventy-five patients with AD (87.2%) and 13 of the mixed group (76.5%) had abnormal EEGs on first testing, giving a sensitivity of 87.2% for uncomplicated AD. Ultimately, 79 (92%) of 86 patients with AD had abnormal EEGs. Twenty (35%) of 56 EEGs for matching control subjects were abnormal. Moderately abnormal or severely abnormal EEGs were found in 10 (50%) of 20 of the patients with AD of less than 4 year's duration compared with two (4.1%) of 49 of the control subjects, giving a specificity of 95.9% for EEGs with this degree of abnormality. The normal EEG had a negative predictive value of 0.825 with respect to the diagnosis of AD in these populations.

CONCLUSIONS

Widespread availability, low cost, and high sensitivity support the use of the awake EEG in the diagnosis of AD.

Lack of difference in brain hyperintensities between patients with early Alzheimer's disease and control subjects

OBJECTIVE

To rate magnetic resonance image signal hyperintensities in clearly defined white and deep gray matter areas in patients with early Alzheimer's disease and controls.

DESIGN

Prospective series. The National Institute for Neurological Disorders and Stroke--The Alzheimer's Disease and Related Disorders Association criteria for probable Alzheimer's disease. Blinded assessment.

SETTING

University hospital, dementia study group.

SUBJECTS

Thirty-four patients with Alzheimer's disease. Thirty-eight age-matched healthy community volunteers.

MEASURES

Frequency of hyperintensities in axial magnetic resonance images (1.5-T system) seen both in the proton density and T2-weighted scans examined in vascular centrencephalon, centrum semiovale, watershed, periventricular, and subcortical white matter. Periventricular hyperintensities classification include caps, thin lining, and smooth and irregular halo. Hyperintensities in other areas include small and large focal, focal confluent, and diffusely confluent. The hyperintensities were counted and rated using a five-point scale and the Fazekas method.

RESULTS

No difference in the ratings, frequency, or extent of the hyperintensities between patients with early Alzheimer's disease and controls. Majority of patients and controls had two or fewer hyperintensities and they were mostly small foci, caps, and thin linings. The hyperintensities are associated with arterial hypertension, diabetes, cardiac disorder, and age in different combinations, but not with Alzheimer's disease.

CONCLUSION

Tiny hyperintensities on magnetic resonance images are frequent both in patients with early Alzheimer's disease and in healthy controls; most of the lesions are not related to brain ischemia. When age and vascular risk factors were taken into account, no difference between patients with early Alzheimer's disease and control subjects could be detected.

Significance of plaque ulceration in symptomatic patients with high-grade carotid stenosis. North American Symptomatic Carotid Endarterectomy Trial

BACKGROUND AND PURPOSE

The importance of carotid plaque ulceration as a cause of cerebral ischemic symptoms remains uncertain. Moreover, its prominence in symptomatic patients with severe carotid stenosis is unknown.

METHODS

The association between angiographically defined plaque ulceration and risk of subsequent stroke was assessed using Cox proportional hazards regression in 659 patients with severe (70% to 99%) carotid stenosis from the North American Symptomatic Carotid Endarterectomy Trial.

RESULTS

Treatment assignment (medical versus surgical) and degree of ipsilateral stenosis were identified as having a significant influence on the results. The risk of ipsilateral stroke at 24 months for medically treated patients with ulcerated plaques increased incrementally from 26.3% to 73.2% as the degree of stenosis increased from 75% to 95%. For patients with no ulcer, the risk of stroke remained constant at 21.3% for all degrees of stenosis. The net result yielded relative risks of stroke (ulcer versus no ulcer) ranging from 1.24 (95% confidence interval, 0.61 to 2.52) to 3.43 (95% confidence interval, 1.49 to 7.88). Conversely, for surgically treated patients with antecedent presence of an ulcerated plaque, the risk of stroke increased slightly at the highest degrees of stenosis. Overall, carotid endarterectomy reduced the risk of ipsilateral stroke at 24 months by at least 50%. Similar results were obtained for risk of major ipsilateral stroke and risk of all strokes and death.

CONCLUSIONS

The presence of angiographically defined ulceration for medically treated symptomatic patients is associated with an increased risk of stroke. The risk of stroke more than doubles at higher degrees of stenosis. Carotid endarterectomy is beneficial in substantially reducing the risk of stroke, regardless of plaque ulceration and degree of severe carotid stenosis.

The clinical problem of brain and heart

Observations in an intensive care stroke unit showed that patients recovering from stroke sometimes perish unexpectedly from cardiac complications or sudden death. Compared with control subjects, stroke patients more often have cardiac arrhythmias, raised cardiac enzymes, and elevated plasma norepinephrine, suggesting a hypersympathetic state. We have found that involvement of the insula by experimental cerebral infarction is crucial in mediating the cardiac complications. Age and right as opposed to left hemisphere involvement represent additional risks for the cardiac complications of experimental stroke. These experimental observations now need to be tested clinically.

Cardiac and sympathetic effects of middle cerebral artery occlusion in the spontaneously hypertensive rat

Acute increases in sympathetic activity, plasma catecholamine concentrations and myocardial damage, occur following middle cerebral artery occlusion (MCAO) in Wistar rats. Hypertension is a major risk factor for stroke. The autonomic responses to MCAO in the spontaneously hypertensive (SHR) and Wistar-Kyoto (WKY) rats were therefore investigated. Arterial pressure (AP), heart rate (HR), renal sympathetic nerve discharge (SND), plasma catecholamines and ECG were measured in 16 SHR and 16 WKY male urethane-anesthetized rats, which were subjected to either MCAO or sham MCAO. Cerebral infarct size did not differ between SHR and WKY rats, as shown by tetrazolium staining. Initial AP was significantly higher in SHR (96 +/- 4 mmHg) than in WKY (70 +/- 1 mmHg; P < 0.05). No significant differences in initial HR or plasma catecholamine levels were observed between SHR and WKY. By 6 hours after MCAO, AP, SND and plasma epinephrine in SHR decreased significantly, while HR showed a significant increase. SND and plasma catecholamines in the WKY showed increases that did not reach significant levels following MCAO. The QT interval of the ECG was significantly prolonged in the WKY MCAO rats, which also had a higher frequency of cardiac myocytolysis than the other groups. Unlike the increases in autonomic variables following MCAO in Wistar rats, SHR exhibit significant decreases in SND and AP, while WKY show slight, but non-significant increases. These differences in the autonomic reaction to MCAO may reflect genetic differences in the response to cerebral ischemia.

Pathologic correlates of increased signals of the centrum ovale on magnetic resonance imaging

The pathologic correlates of increased signal in the white matter of the centrum ovale in postmortem magnetic resonance imaging were investigated in an unselected series of 15 autopsies. Two types of magnetic resonance imaging hyperintensities could be separated on the basis of size (10-mm cutoff): extensive and punctate. The pathologic basis of extensive hyperintensities was large areas of pallor with ill-defined margins, located in the central white matter and sparing the subcortical U fibers on both myelin and axonal stains. Microscopically, these areas showed diffuse vacuolation and significant reduction in the areal densities of glial cells. This change was never seen in areas that did not show extensive white matter hyperdensities on magnetic resonance imaging. The correlates of punctate magnetic resonance imaging hyperintensities were less well defined; dilated Virchow-Robin spaces probably represent a common cause of this phenomenon.

Temporal lobe atrophy on magnetic resonance imaging in the diagnosis of early Alzheimer's disease

OBJECTIVE

To evaluate the use of simple ratings and linear measures of atrophy in the temporal lobe structures obtained with magnetic resonance imaging coronal scans in the diagnosis of early Alzheimer's disease.

DESIGN

Prospective series. The National Institute for Neurological Disorders and Stroke-Alzheimer's Disease and Related Disorders Association criteria for probable Alzheimer's disease. Blinded assessment.

SETTING

Dementia study in a university hospital.

SUBJECTS

Patients with Alzheimer's disease (n = 34), scoring 150 or more on the Extended Scale for Dementia, and age-matched healthy community volunteers (n = 39) who had both magnetic resonance imaging coronal scans and a psychometric assessment using the Extended Scale for Dementia within 6 months were included.

MEASURES

MAIN MEASURES

T1-weighted magnetic resonance imaging coronal scans, a 1.5-T system. The degree of atrophy rated (0 to 4) in both sides of the temporal neocortex, entorhinal cortex, hippocampal formation, temporal horns, third ventricle, lateral ventricles, and frontal and parietal cortex. Linear measures: the area of hippocampus and the maximal transverse width of temporal horns.

RESULTS

Differentiation between patients with Alzheimer's disease and controls was limited by considerable variations in sensitivity and specificity. Receiver operating characteristics analysis revealed a clear order of discrimination, the entorhinal cortex and the temporal neocortex being the two best, followed by the temporal horns and hippocampal formation. For a given specificity of 90%, the corresponding sensitivity for the entorhinal cortex, temporal neocortex, temporal horns, and hippocampal formation was 95%, 63%, 56%, and 41%, respectively. Linear measures differed significantly but showed considerable overlap.

CONCLUSION

The presence of rated atrophy in selected temporal structures makes the diagnosis of Alzheimer's disease more likely, but the absence does not rule out the possibility of early Alzheimer's disease.

Prevention of ischemic stroke: the role of carotid endarterectomy in symptomatic patients

Carotid endarterectomy (CE) has recently been proved to be beneficial in symptomatic patients with severe (70-99%) appropriate carotid stenosis. After discussing the historical evolution of CE as a possible preventive treatment of ischemic stroke, we review the results of North American and European trials in order to give practical information for the management of cerebrovascular patients.

Cardiovascular effects of human insular cortex stimulation

Recent investigations indicate a site of cardiac representation within the left insular cortex of the rat. Moreover, the results of lesion studies suggest left-sided insular dominance for sympathetic cardiovascular effects. It is unclear whether similar representation exists within the human insular cortex. Five epileptic patients underwent intraoperative insular stimulation prior to temporal lobectomy for seizure control. On stimulation of the left insular cortex, bradycardia and depressor responses were more frequently produced than tachycardia and pressor effects (p less than 0.005). The converse applied for the right insular cortex. We believe this to be the first demonstration of cardiovascular changes elicitable during insular stimulation in humans, and of lateralization of such responses for a cortical site. In humans, unlike the rat, there appears to be right-sided dominance for sympathetic effects. These findings may be of relevance in predicting the autonomic effects of stroke in humans and in the explanation of sudden unexpected epileptic death.

Asymmetry of sympathetic consequences of experimental stroke

Asymmetries of sympathetic regulation at the level of the inferior cervical ganglia have long been recognized. Lateralization of autonomic representation may also occur in the brain, since inactivation of the left and right hemispheres by intracarotid amobarbital produces an increase and decrease in heart rate, respectively. However, this conclusion has remained tentative, since the differential effect of lateralized brain lesions on sympathetic activity has not been studied systematically. Forty-eight urethan-anesthetized Wistar rats were divided into three groups: a group given left middle cerebral artery occlusion, and a group given sham operation. Heart rate, mean arterial blood pressure, renal sympathetic nerve discharge, and electrocardiogram were monitored throughout the 4-hour experiments. Plasma epinephrine and norepinephrine levels were measured at baseline and 1 and 4 hours after occlusion or sham occlusion. The mean arterial pressure decreased in the group given sham operation and to lesser extent in the group given left middle cerebral artery occlusion. By contrast, mean arterial pressure did not fall in the group given right middle cerebral artery occlusion and at 4 hours was significantly higher than control values in the sham-occluded rats. Renal sympathetic nerve discharge was decreased in the sham-occluded group, increased significantly from 20 minutes to 2 hours in the group given left middle cerebral artery occlusion, and increased from about 20 minutes to the end of the experiment in the group given right middle cerebral artery occlusion. The plasma norepinephrine level was significantly elevated at 1 hour (93%) and 4 hours (44%) only in the group given right middle cerebral artery occlusion.(ABSTRACT TRUNCATED AT 250 WORDS)

Effect of age on autonomic and cardiac responses in a rat stroke model

The cardiovascular system and its responses change with increasing age. This has seldom been considered in experimental models of stroke, although most strokes occur in the elderly. We studied 57 male Wistar rats in three age groups: 47 to 70 days old (juvenile), 110 to 152 days old (young adult), and 186 to 245 days old (mature adult), each group being subdivided into experimental and sham operation groups. All rats underwent occlusion or sham occlusion of the left middle cerebral artery and monitoring of the mean arterial blood pressure, heart rate, sympathetic nerve activity, plasma catecholamine levels, and electrocardiogram. Eight of the 12 rats in the oldest group died within 6 hours of the middle cerebral artery occlusion; of these, the youngest was 186 days old. The mature adult rats that died before completion of the experiment showed the highest level of sympathetic nerve activity and the only significant increase in the QT interval of the electrocardiogram. Following middle cerebral artery occlusion, sympathetic nerve activity increased in the young adult rats but most strikingly in the mature adult rats that died before the end of the 6-hour experiments. Plasma norepinephrine levels were significantly elevated at 4 and 6 hours after middle cerebral artery occlusion in the oldest group and only at 6 hours in the juvenile rats. The results of this study are consistent with impaired sympathetic and cardiovascular regulation in the mature adult rat. High sympathetic activity may represent one mechanism leading to fatal cardiac arrhythmias. Age-related impairment of sympathetic regulation may contribute to the higher mortality seen among elderly patients with stroke.

Endarterectomy for symptomatic carotid stenosis. Review of the European and North American Symptomatic Carotid Surgery Trials

The recent results of two major multicenter trials, ECST (European Carotid Surgery Trialists') and NASCET (North American Symptomatic Carotid Endarterectomy Trial), show benefit of carotid endarterectomy for patients with recent (4-6 months), nondisabling, carotid distribution, cerebral ischemic events (hemispheric and retinal TIA or stroke) and ipsilateral severe (70-99%) carotid stenosis provided that perioperative mortality remains low. ECST, in addition, failed to demonstrate the benefit of surgery for patients with mild stenosis (0-29%). The comparisons between the studies in regards to methodology, measurements, and complications are discussed.

The impact of magnetic resonance imaging on the management of acute ischemic stroke

Despite rapid advances in imaging technology, the etiology of stroke remains unestablished in 40% of patients. MRI improves localization in acute stroke. However, it is not known whether "accurate localization" results in better management. We reviewed the hospital records of all patients admitted with a diagnosis of acute ischemic stroke and who had had cranial CTs and MRI within 10 days of admission. Between January 1987 and June 1990, 116 patients (69 men, 47 women; mean age, 66 years) were identified. Compared with CT localization, infarcts were better localized in nine of 39 patients with cerebral cortical lesions, in 20 of 22 patients with brainstem and cerebellar lesions, and in three of three patients with isolated cerebellar lesions. In 22 patients (18.9%), MRI showed multiple infarcts in two or more vascular territories, suggesting embolic disease and leading to anticoagulation. MRI also showed arterial occlusions in 11 patients (9.5%). Based on the information obtained with MRI, the clinical diagnosis was changed in 19 patients (16.3%), resulting in changes in the management of most of those patients. Thus, we confirm earlier reports that MRI improves localization after acute cerebral infarction and show that such information alters patient management.

The cardiac consequences of stroke

Stroke, whether ischemic or hemorrhagic, induces cardiac damage by nonischemic mechanisms. The evidence derives from autopsy studies and investigation of ECG, cardiac enzyme changes, and plasma catecholamine changes after stroke. Increased sympathoadrenal tone, resulting from damage to cortical areas involved in cardiac and autonomic control is the likely cause. Recent experimental evidence indicates that the insular cortex plays a principal role in stroke-related cardiac damage.

The cardiac factor in stroke

Cardiac disorders associated with cerebral embolism including cardiac surgery, myocardial infarction, endocarditis and non-valvular atrial fibrillation (NVAF) are reviewed along with methods to detect cardioembolic sources. Warfarin and aspirin are effective in the primary prevention of stroke in NVAF but the relative efficacy remains to be determined.

An examination of psychometric properties of the extended scale for dementia in three different populations

The Extended Scale for Dementia (ESD), a development of the Mattis Dementia Rating Scale, has been used in the evaluation of dementia and aging and has shown substantial clinical utility. We report on analyses of its properties and internal structure in three samples of older people: 153 normals, 101 psychiatric hospital residents, and 114 patients with Alzheimer disease. The results showed good internal consistency in the two clinical samples, with much lower reliability in the normals, for whom the test was too easy. A review of the item statistics led to the use of 17 of the 23 ESD items in item component analyses in the three samples. Use of Horn's parallel analysis criterion led to the retention of three components in the normal group and one in both the hospital and Alzheimer groups. The results are compared with other work and are in accordance with the view that cognitive structure becomes more simple with increasing dementia.

Clinical correlates of white-matter changes on magnetic resonance imaging scans of the brain

We report our observations on the clinical and radiologic correlates of changes in cerebral white matter based on 94 subjects undergoing magnetic resonance imaging in a prospective study of dementia. Periventricular hyperintensity occurred twice as often in patients with Alzheimer's disease as in healthy control subjects. Within the control group, the presence of periventricular hyperintensity correlated significantly with one measure of cerebral atrophy and with the presence of changes in the adjoining deep white matter. The significance of white-matter changes distinct from the ventricles (leuko-araiosis) remains unsettled. Leuko-araiosis on the magnetic resonance imaging scan, unlike its correlate on the computed tomographic scan, was not shown to relate to cognitive decline or to the presence of focal abnormalities on neurologic examination. This is likely to reflect the heterogeneity of the changes detected with magnetic resonance imaging and their limited extent in our subjects.

Improved recognition of leukoaraiosis and cognitive impairment in Alzheimer's disease

We identified 85 patients in a longitudinal study of dementia who had uncomplicated Alzheimer's disease and in whom computed tomography of the head and psychometric testing were conducted within a 6-month period following their entry into the study. Thirty-four patients (40%) had leukoaraiosis, which was disproportionately common in female patients (62% vs 15% in male patients). Analysis of covariance demonstrated a relative reduction of scores on the Extended Scale for Dementia in those patients who had leukoaraiosis, after adjusting for the confounding effects of age, sex, educational level, and duration of illness. Leukoaraiosis was also much more common in women, even after adjusting for the possible confounding effects of age, duration of illness, Extended Scale for Dementia score, and hypertension. Multiple regression analysis showed that leukoaraiosis accounted for 11.6% of the variance of the Extended Scale for Dementia scores. Leukoaraiosis, together with duration of illness, accounted for 18.2% of the variance. Leukoaraiosis is associated with a greater degree of cognitive impairment in patients with Alzheimer's disease.

Mechanisms and management of stroke in the elderly

OBJECTIVE

To highlight the mechanisms, common causes and management of stroke in the elderly.

DATA SOURCES

MEDLINE was searched for articles published from 1967 to 1990. The following key words were used: "stroke," "cerebrovascular disease," "elderly," "aging," "hypertension," "drug interactions," "etiology," "evaluation," "management" and "recovery of function." Original articles with large series of patients were reviewed in detail.

STUDY SELECTION

Of about 750 original articles reviewed 116 were finally selected for detailed analysis. Those that dealt with cause, pathophysiologic features and management of stroke with emphasis on the elderly were chosen.

DATA SYNTHESIS

With increasing age the incidence of stroke increases, cardiovascular reserve decreases, catecholamine responsiveness diminishes and cardiac arrhythmias become more common. Blood pressure, especially systolic, rises, and the benefits of its treatment become both more difficult to assess and less certain. In the elderly population embolic stroke, particularly that due to nonvalvular atrial fibrillation, is seen with increasing frequency. Because of postural hypotension, cardiac arrhythmias and overmedication, watershed infarction occurs more frequently with increasing age. Amyloid angiopathy now represents the most common cause of spontaneous intracerebral hemorrhage.

CONCLUSIONS

Because of the altered drug metabolism and pharmacodynamics in the elderly the therapeutic armamentarium is growing, and so are the risks of such treatments. Stroke in the elderly poses unique problems that deserve distinctive solutions. Further research is needed to study the effect of cerebral ischemia to understand better how the older brain handles the stress of the ischemic insult.

Beneficial effect of carotid endarterectomy in symptomatic patients with high-grade carotid stenosis

BACKGROUND

Without strong evidence of benefit, the use of carotid endarterectomy for prophylaxis against stroke rose dramatically until the mid-1980s, then declined. Our investigation sought to determine whether carotid endarterectomy reduces the risk of stroke among patients with a recent adverse cerebrovascular event and ipsilateral carotid stenosis.

METHODS

We conducted a randomized trial at 50 clinical centers throughout the United States and Canada, in patients in two predetermined strata based on the severity of carotid stenosis--30 to 69 percent and 70 to 99 percent. We report here the results in the 659 patients in the latter stratum, who had had a hemispheric or retinal transient ischemic attack or a nondisabling stroke within the 120 days before entry and had stenosis of 70 to 99 percent in the symptomatic carotid artery. All patients received optimal medical care, including antiplatelet therapy. Those assigned to surgical treatment underwent carotid endarterectomy performed by neurosurgeons or vascular surgeons. All patients were examined by neurologists 1, 3, 6, 9, and 12 months after entry and then every 4 months. End points were assessed by blinded, independent case review. No patient was lost to follow-up.

RESULTS

Life-table estimates of the cumulative risk of any ipsilateral stroke at two years were 26 percent in the 331 medical patients and 9 percent in the 328 surgical patients--an absolute risk reduction (+/- SE) 17 +/- 3.5 percent (P less than 0.001). For a major or fatal ipsilateral stroke, the corresponding estimates were 13.1 percent and 2.5 percent--an absolute risk reduction of 10.6 +/- 2.6 percent (P less than 0.001). Carotid endarterectomy was still found to be beneficial when all strokes and deaths were included in the analysis (P less than 0.001).

CONCLUSIONS

Carotid endarterectomy is highly beneficial to patients with recent hemispheric and retinal transient ischemic attacks or nondisabling strokes and ipsilateral high-grade stenosis (70 to 99 percent) of the internal carotid artery.

Assessment of therapeutic effects in ischemic stroke

The three fundamental methods of assessing the therapeutic effects in ischemic stroke are measurements of mortality, morbidity and quality of life. Increasingly more sophisticated cerebral blood flow and metabolism determinations are allowing insights into pathophysiology and giving guidance to the most promising therapeutic approaches. Experimental work and pathophysiological studies provide the scientific basis for therapy, but the assessments that ultimately matter to the patient are clinical, and preferably ones derived from controlled clinical trials.

Stroke and hypertension and its prevention

Systolic and diastolic hypertension in both men and women is a well-established risk factor for the development of ischemic and hemorrhagic stroke. Antihypertensive treatment decreases the risk, but questions remain as to the precise level of hypertension to be treated, whether the effects of antihypertensive treatment are blunted with increasing age, and the best type of antihypertensive drug or combination of drugs to be used. Further questions remain concerning the incidence of pseudohypertension and the potentially harmful effects of its treatment on the brain, and the possibility that fluctuations in blood pressure may be worse than elevation alone. A pragmatic approach would be to treat hypertension with vigor in the young, with caution in the mature, and with reluctance in the old.

Multi-infarct dementia: a reappraisal

Multi-infarct dementia (MID) may not be the only or even the most important form of vascular dementia. Vascular factors probably contribute to dementia through cerebral infarcts and white matter changes more often than they cause it. More subtle ischemic insults affecting synapses, cells, or protein synthesis without causing frank infarction remain plausible but unproven postulates. Lest we regress to vague and comforting notions of silting blood vessels and ailing neurons, let us recognize that although MID may not explain all of vascular dementia, it has the virtue of being a firm, testable concept. As such it has not been overthrown or even seriously challenged. But it is time for a reappraisal.

Racial differences in the anterior circulation in cerebrovascular disease. How much can be explained by risk factors?

The entry characteristics of 1367 patients enrolled into the Extracranial/Intracranial Bypass Study were examined to determine if site differences in intracranial and extracranial arterial lesions among racial groups could be explained by differences in risk factors. Blacks were more often hypertensive, diabetic, or cigarette smokers, while whites had higher systolic blood pressure and hemoglobin values. Orientals had the lowest prevalence of vascular risk factors. Despite these differences in risk factors, multivariate analysis showed race to be an independent and strong predictor of the location of cerebrovascular lesions. To our knowledge, this study is unique in documenting risk factors prospectively and systematically in three racial groups simultaneously. Although generalization is limited by possible biases related to patient selection, the results affirm previous tentative conclusions about the role of race in determining the location of cerebrovascular disease.

Clinical recovery and sleep architecture degradation

We achieved a unique and timely recording of cerebral activity in a 70 year old woman immediately pre- and post-stroke, while studying the effect of acute cerebral infarction on sleep-electroencephalogram (EEG) patterns. Normal patterns, except for increased wakefulness, were recorded during two pre-infarct polysomnograms. Immediately following cerebral infarction increased delta activity was recorded from the infarcted hemisphere only. Initially, REM sleep could not be recorded from either side; however, on the third post infarct day REM sleep returned. Background EEG levels from both hemispheres became progressively slower, flatter and simpler. In addition, sleep spindles and the distinctive saw-tooth wave forms of sleep almost disappeared. At one year post-stroke sleep-EEG rhythm recordings from both hemispheres became more similar except for persisting delta activity from the left hemisphere. Unexpected deterioration of sleep-EEG pattern recordings from the undamaged hemisphere taken during the patient's clinical recovery remains unexplained. Serial sleep recording may facilitate the study of brain recovery, activity and reorganization following stroke.