Slowly progressive aphasia: three cases with language, memory, CT and PET data.

Three cases of slowly progressive speech and language disturbance were studied at various points post onset (three, five and 15 years respectively). Language, neuropsychological and brain imaging (computer tomography and positron emission tomography) evaluations were completed on all three patients. The data suggest that the syndrome of "progressive aphasia": 1) does not involve a uniform symptom complex; 2) does not necessarily develop into a full blown dementia syndrome; 3) varies greatly in rate of progression from case to case; 4) is associated with normal brain structure (on computer tomography); and 5) is associated with abnormal left temporal lobe metabolism as measured by fluorodeoxyglucose (FDG) positron emission tomography (PET).

PET and P300 relationships in early Alzheimer's disease.

The P300 (P3) wave of the auditory brain event-related potential was investigated in patients with probable Alzheimer's disease to determine whether P300 latency discriminated these patients from controls and whether prolonged P300 latency correlated with rates of brain glucose metabolism as measured by Positron Emission Tomography. P300 latency was prolonged by more than 1.5 standard deviations from age expectancy in 14 of 18 patients, but none of 17 controls.

Increased false alarms in a subset of persons at-risk for Huntington's disease.

The accuracy and decision criterion of 51 persons at-risk (AR) for Huntington's disease (HD) along with 36 age-matched, healthy controls were evaluated using a word recognition memory test. Analyses revealed that the AR group was less accurate than the controls at recognizing a previously learned word list. Within the AR group, 13 AR persons were identified who committed significantly more false alarms than the remaining AR and control people.

Cerebral glucose metabolic patterns in Alzheimer's disease. Effect of gender and age at dementia onset.

No previous study of Alzheimer's disease has, to our knowledge, assessed the effect of both age at dementia onset and gender on cerebral glucose metabolic patterns. To this end, we used positron emission tomography (fludeoxyglucose F 18 method) to study 24 patients with clinical diagnoses of probable Alzheimer's disease. Comparisons of the 13 patients with early-onset dementia (less than 65 years of age) with the 11 patients with late-onset dementia (greater than 65 years of age) revealed significantly lower left parietal metabolic ratios (left posterior parietal region divided by the hemispheric average) in the early-onset group.

Memory impairments in alcoholism: effects of age and education.

Memory impairments related to alcoholism and to age (young, middle, and old) were examined as a function of educational level (low, high). Factoring of 14 different memory test scores from 93 alcoholics and 73 controls into four components indicated that alcohol-related impairments in verbal memory were observed in adults with low, but not high levels of education. Similarly, age-related decrements in visual-spatial and verbal memory tasks (Components I and II) affected mainly low-education alcoholics and controls.

Subcortical structures in aphasia. An analysis based on (F-18)-fluorodeoxyglucose, positron emission tomography, and computed tomography.

Subcortical structural damage that includes the anterior and posterior internal capsule, caudate, thalamus, lenticular nuclei, and insula has been shown to cause aphasias. A critical question that has not been resolved is whether the role of these structures on behavior is a direct one or whether it is indirect through the cortex. We have used pathway analysis to evaluate computed tomography, glucose metabolic, and language data from 47 aphasic patients to answer this question.

Apparent shift in visual field preference after unilateral stroke.

Patients with either a left- or a right-hemisphere stroke lesion scored higher in tasks of word-picture matching and of nonverbal shape matching when information was presented tachistoscopically (120 msec) to the visual field (VF) projecting to their undamaged hemisphere. Left-hemisphere stroke patients (n = 13) were dissociated from right-hemisphere stroke patients (n = 15) by low word recognition from memory and by low right VF but nearly normal left VF accuracy in word-picture matching or shape matching; the former appeared to rely upon processing of word meaning by the right hemisphere. In contrast, right-stroke patients had higher right than left VF scores in both tasks, and their discrimination of nonverbal shapes via the right VF was not different from that of controls (n = 15).

Disconnection and cerebral metabolism. The case of conduction aphasia.

Ten patients with conduction aphasia were studied with computed tomography and 18-F-fluorodeoxyglucose positron emission tomography to examine glucose metabolism. Computed tomographic results identified a postrolandic structural locus for conduction aphasia. All patients demonstrated resting glucose hypometabolism throughout the parietal and temporal regions, and half of the patients also demonstrated reduced metabolic rates in the posterior, inferior, frontal (Broca's) regions.

Cognitive and brain imaging measures of Alzheimer's disease.

Diagnosis of Alzheimer's disease (AD) during life relies upon clinical and neurobehavioral symptoms but is presumptive without microscopic verification of neuropathology. Studies in this review observed considerable heterogeneity in AD symptoms and did not agree on how to detect the earliest symptoms. Problems exist in diagnosis.

Cerebellar glucose metabolism in chronic aphasia.

(18F)-Fluorodeoxyglucose PET was used to compare left/right cerebellar hemispheric glucose metabolism in 37 aphasic patients with left hemisphere lesions and 22 age-matched controls. Sixteen aphasic subjects showed cerebellar symmetry. Twenty-one aphasic subjects were found to have cerebellar metabolic asymmetry, which (1) resulted from an absolute reduction in local cerebral metabolic rates of glucose in the right cerebellar hemisphere; (2) was associated with left less than right glucose metabolic asymmetry in the frontal, parietal, caudate, and thalamic regions; (3) was associated with Broca's region and deep hemisphere structural damage to the internal capsule and basal ganglia; (4) related to reduced functional motor performance, spontaneous speech, naming, reading, and writing; and (5) included all Broca's aphasia subjects.

Reduced cerebral glucose metabolism in asymptomatic subjects at risk for Huntington's disease.

Symptomatic patients with Huntington's disease may have reduced glucose metabolism in the caudate nuclei. We used positron emission tomography and [18F]fluorodeoxyglucose to study cerebral glucose metabolism in 95 subjects: 58 clinically asymptomatic (chorea-free) subjects at risk for Huntington's disease, 10 symptomatic patients with the disease, and 27 controls. All the symptomatic patients had marked reductions in caudate glucose metabolism.

Specificity of memory deficits in alcoholism.

Inferences of specific impairments in memory from prolonged abuse of alcohol have come from initial studies reporting that visuospatial memory and problem solving were impaired but verbal memory and learning were not. The apparent specificity, however, is demonstrated to be an artifact of the more difficult visual tests. With task complexity increased, impairments are shown also in both learning and recall of words, story, or designs.

Left hemisphere intracerebral hemorrhages studied by ( (F-18)-fluorodeoxyglucose PET.

We used PET to study patients with intracerebral hemorrhages in the left hemisphere. Three anatomic and physiologic patterns were observed. Patients 1 and 2 had midputamen hemorrhages with diffuse left less than right hemispheric metabolic asymmetry most prominent in temporal and parietal regions.

Comparison of PET measurement of local brain glucose metabolism and CAT measurement of brain atrophy in chronic schizophrenia and depression.

Using [18F]fluorodeoxyglucose and positron emission tomography (PET), the authors examined the regional brain glucose metabolism of six patients with chronic schizophrenia, six patients with chronic depression, and 12 normal control subjects. Three schizophrenic and four depressive patients had CAT scans that showed enlarged ventricles (ventricle-brain ratios higher than 9.0) and widened sylvian fissures.

Aging and delay effects on recognition of words and designs.

Based on a model of inter- and intraitem processes in recognition, this study examined age differences in word recognition (emphasizing interitem elaborative rehearsal) and in design recognition (emphasizing intraitem perceptual processes) over delays of 2, 20, and 200 min. Because repeated exposures should increase intraitem integration, targets were repeated from first to second test halves. Young and old adults showed equivalent accuracy in design recognition and equivalent increases from first to second test halves; the predicted lack of intraitem age differences was supported.

Brain glucose metabolism and memory functions: age decrease in factor scores.

The F-18 fluorodeoxyglucose (FDG) scan method with positron emission tomography was used to determine age differences in factors underlying both the performances on 18 multivariate memory tests and the rates of cerebral glucose utilization in nine left and nine right hemispheric regions of 23 healthy adults aged 27 to 78 years. Two of the five derived factors separated persons below age 42 from those above age 48 years, one reflecting secondary memory for material verbally processed together with Broca's metabolic ratio, the other defined by tests requiring sequential or organizational coding of information and metabolic measures of thalamic regions. Education did not override their parallel age decrease.

Patterns of cerebral glucose utilization in depression, multiple infarct dementia, and Alzheimer's disease.

Patterns of local cerebral glucose utilization were determined in moderately to severely disabled patients with D (N = 7), MID (N = 6), and AD (N = 6), and in normal controls (N = 6), using positron emission tomography with the 18F-fluorodeoxyglucose method. Average global metabolic rate was decreased 30% in patients with AD, but overlap among the other groups reduced the discriminant value of this measure. In depressed patients, the cerebral metabolic pattern was normal, except for evidence of hypometabolic zone in the posterior-inferior frontal cortex which was of marginal statistical significance.

Local cerebral glucose utilization in symptomatic and presymptomatic Huntington's disease.

Patterns of local cerebral glucose utilization were measured with positron emission CT using the 18F-fluorodeoxyglucose method in 13 patients with HD, 15 subjects at risk for HD, and control subjects. These data were compared with CT measures of cerebral atrophy, age, and duration and severity of symptoms. The results indicate that in HD there is a characteristic decrease in glucose utilization in the caudate and putamen and that this local hypometabolism appears early and precedes bulk tissue loss.

Cerebral metabolic relationships for selected brain regions in Alzheimer's, Huntington's, and Parkinson's diseases.

Local CMRGlc values were determined for 13 regions in each hemisphere from tomographs of patients with Alzheimer's, Huntington's, and Parkinson's diseases who were studied using [18F]fluorodeoxyglucose with positron emission computed tomography. Intercorrelations among the 26 regional measures were calculated for each disease state and for normal controls, and were accepted as reliable at p less than 0.01, uncorrected for the number of comparisons.

Awake abnormalities of control of breathing and of the upper airway. Occurrence in healthy older men with nocturnal disordered breathing.

We hypothesized that preexisting diminished chemical control of breathing and narrowing of the upper airway are associated with sleep-related disordered breathing (SRDB) in healthy older men. Twenty-six subjects, aged 55 to 70, were studied. An SRDB episode was a decrease in arterial oxygen saturation (SaO2) of at least 4 percent.

Local cerebral metabolic rates of glucose in movement and language disorders from positron tomography.

Positron-computed tomography with [18F]fluorodeoxyglucose to measure glucose metabolism has shown changes in the brain distant to a focal area of infarction, demonstrating that what appears as a focal abnormality represents a more widespread functional process. Several approaches are presented to better understand quantitative metabolic data and focus on caudate and basal ganglia function. Area-to-area correlations in Parkinson's and Huntington's diseases showed decreases in the number of cortical relationships compared with control subjects, suggesting that the basal ganglia are involved with the ability of cortical regions to function together.

Patterns of local cerebral glucose utilization determined in Parkinson's disease by the [18F]fluorodeoxyglucose method.

[18F]Fluorodeoxyglucose scans were performed on 9 patients with Parkinson's disease and 14 normal subjects. Five patients were restudied after an interval of 3 to 4 years. We found no selective metabolic change in striatum, where dopamine deficit is known to be greatest, in affected patients; cerebral glucose metabolism was reduced uniformly throughout the parkinsonian brain (average 18% decrease).

Cerebral metabolic relationships for selected brain regions in healthy adults.

The local cerebral metabolic rate for glucose was determined in 26 regions of the brain in 31 healthy subjects who underwent resting fluorodeoxyglucose positron emission tomography. Intercorrelations among the 26 regional measures were accepted as reliable at p less than 0.01 (r greater than 0.