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Biomedical subjects

W H Riege

Publications and source records attributed to W H Riege.

At least 37 records · Page 2Linked to original sources
PubMed1984

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). With increased severity of bradykinesia and the development of mild to moderate dementia, global brain metabolism in Parkinson's disease decreased further. In one moderately demented patient with Parkinson's disease, severe parietal cortex hypometabolism was found, similar to that seen in Alzheimer's disease. In contrast, mildly to moderately demented patients with Huntington's disease have marked caudate hypometabolism, but cerebral glucose metabolism is normal elsewhere. It appears that in addition to the well-known neurotransmitter loss in the nigrostriatal system, there is an abnormal metabolic process involving neurons throughout the parkinsonian brain.

Aged↗
PubMed1984

Patterns of cerebral glucose utilization in Parkinson's disease and Huntington's disease.

Patterns of local cerebral glucose utilization were measured with positron emission tomography using the fluorine-18-labeled fluorodeoxyglucose (18FDG) method in 8 patients with Parkinson's disease, in 13 patients with Huntington's disease, in 15 subjects at risk for Huntington's disease, and in aged-matched normal control subjects. On the average, global cerebral metabolism in patients with Parkinson's disease was moderately reduced (20%), but the relative distribution of glucose utilization throughout the brain in these patients was normal. These results support the conclusion that alterations of the nigrostriatal pathway in Parkinson's disease have no major selective effect on the metabolism of particular cerebral regions. In Huntington's disease, however, there was a characteristic decrease in glucose utilization in the caudate nuclei and putamen, and this local hypometabolism appeared early and preceded bulk tissue loss. In patients with Huntington's disease, glucose utilization typically was normal throughout the rest of the brain, regardless of the severity of symptoms and despite the apparent shrinkage of brain tissue. The results also suggest the possibility that the caudate nuclei may be hypometabolic in some asymptomatic subjects who are potential carriers of the autosomal dominant gene for Huntington's disease.

Adolescent↗
PubMed1984

The effect of normal aging on patterns of local cerebral glucose utilization.

When the fluorine-18-labeled fluorodeoxyglucose (18FDG) scan was applied to 40 normal volunteer subjects aged 18 to 78 years, mean local cerebral metabolic rate for glucose ( lCMRGlu ) declined with advancing age at a faster rate than was reported for mean local cerebral metabolic rate for oxygen. Slopes of decline with age were similar in the centrum semiovale, caudate nucleus, putamen, and overall frontal, temporal, parietal, and occipital cortex. Superior frontal cortex and posterior inferior frontal cortex were exceptions, undergoing more rapid metabolic decline with age than in other parts of the brain. Measurements of the rate constants for transport and phosphorylation process indicate that their change with aging had no major effect on the measurement of lCMRGlu by the 18FDG method.

Adolescent↗
PubMed1984

Correlations of glucose metabolism and structural damage to language function in aphasia.

Studies of aphasic patients using [18F]fluorodeoxyglucose positron computed tomographs have shown areas of metabolic depression in the left hemisphere larger than the area of infarction noted on CT. To evaluate these metabolic differences in relationship to language abnormalities, 11 patients had metabolic scans, CT, and were administered the Boston Diagnostic Aphasia Battery and the Porch Index of Communicative Ability. Correlation analyses were computed between metabolic, CT, and language data. CT demonstrated reliable correlations of speaking, oral reading, and repetition to Wernicke' area, consistent with current anatomic language models, while metabolic data from areas posterior, inferior, and superior to the traditional Wernicke's area and the head of the caudate nucleus also had reliable correlations with aphasic language function. The utilization of both structural and metabolic brain measures may improve our understanding of the anatomy of language as related to aphasia.

Adult↗
PubMed1984

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 0.45), uncorrected for the number of measures. From the matrix two apparently separate functional metabolic systems were identified: (1) a superior system involving the superior and middle frontal gyri, the inferior parietal lobule, and the occipital cortex; and (2) an inferior system involving the inferior frontal, Broca's, and posterior temporal regions. Evidence is presented to suggest that the superior system is involved in visual processing, memory recognition, and decision making, while the inferior system seems to at least participate in language-related functions.

Adult↗
PubMed1984

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. The number of reliable correlations was found to be decreased in Parkinson's and Huntington's diseases, two primarily subcortical disorders, and increased in Alzheimer's disease, a primarily cortical disorder. The changes suggest that one role of the basal ganglia involves coordinating or pacing the ability of cortical brain regions to function as a unit.

Aged↗
PubMed1984

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. In aphasia, caudate metabolism correlated with several language measures that suggested a role in some undefined basic process, seemingly related to Broca's area function. The studies presented suggest that the caudate may involve integrating the processing of language and cognition with the execution of the resulting response. Motor and cognitive function seem related to similar and overlapping brain systems. The disruption of such systems may result in loss of both cognitive and motor aspects of a function.

Aphasia↗
PubMed1983

Comparison of metabolic rates, language, and memory in subcortical aphasias.

Four patients with subcortical lesions and either aphasia or amnesia were compared to four patients with cortical lesions and aphasia. Each patient had [18F] fluorodeoxyglucose positron-emission computed tomography, language, and memory evaluations. Marked metabolic depression was found in the thalamus and caudate in all patients. The subcortical patients had only mild left-cortical changes, while the cortical patients showed marked cortical metabolic changes in the left hemisphere. Language changes were mild in the subcortical patients, while moderate to severe in the cortical patients. All patients showed severe verbal memory dysfunction. The only common abnormalities in the two groups were metabolic changes in the thalamus and severity of verbal memory dysfunction. These findings suggest a relationship between verbal memory and thalamic function.

Adult↗
PubMed1983

Cerebral glucose metabolism as a function of age in man: influence of the rate constants in the fluorodeoxyglucose method.

Measurement of the local cerebral metabolic rate of glucose (LCMRGlc) with the fluorodeoxyglucose (FDG) method requires the utilization of appropriate values for the rate constants of the transport and phosphorylation processes. We measured these rate constants as a function of age to determine whether a decline in LCMRGlc as a function of age, in prior studies with the FDG method, actually represents changes in the rate constants. We found that measurements of LCMRGlc are not significantly affected by changes in rate constants as a function of aging, and that LCMRGlc did not change significantly with age.

Adolescent↗
PubMed1982

Cerebral metabolism and atrophy in Huntington's disease determined by 18FDG and computed tomographic scan.

Patterns of local cerebral glucose utilization were measured with positron emission, computed tomography using the 18F-fluorodeoxyglucose method in 13 patients with Huntington's disease (HD), 15 subjects at risk for HD, and 40 normal control subjects. These data were compared with computed tomographic measures of cerebral atrophy, with age, and with 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. In contrast to patients with senile dementia, in these HD patients glucose utilization typically was normal throughout the rest of the brain, regardless of the severity of symptoms and despite apparent shrinkage of brain tissue. Our results suggest the possibility that the caudate may be hypometabolic in some asymptomatic subjects who are potential carriers of the autosomal dominant gene for HD.

Adolescent↗
PubMed1982

Decision speed and bias after unilateral stroke.

Nonverbal visual memory together with speed and bias in response decisions were evaluated in two experiments comparing patients with a left-hemisphere stroke lesion to those with a right-hemisphere stroke lesion. In the first experiment, the decision times of vocal recognition responses from aphasic (left stroke) patients did not correlate with their verbal scores on the Porch Index of Communicative Ability, taken as an estimate of severity of their language impairment. Thus, impairment of verbal processing was not reflected in speed of response. In the second experiment, 19 left and 19 right-stroke patients were compared with 19 volunteers on a recurrent recognition task of complex nonverbal art designs using measures of discriminability and decision bias derived from Theory of Signal Detection. Right stroke patients had lowest recognition scores but adopted normal decision criteria, whereas left stroke patients employed high negative decision bias (i.e., made few false as well as few correct recognitions). Both stroke groups responded significantly slower than controls; the right stroke patients, however, had markedly fewer long-latency decisions than left stroke patients. Compared with controls, only the speed and bias of decision making were deficient in left stroke patients independent of their verbal deficit; their recognition ability was relatively preserved.

Aphasia↗
PubMed1982

Effects of human aging on patterns of local cerebral glucose utilization determined by the [18F]fluorodeoxyglucose method.

The [18F]fluorodeoxyglucose (FDG) scan method with positron emission computed tomography was used to determine patterns of local cerebral glucose utilization (LCMRglu) in 40 normal volunteer subjects aged 18 to 78 years. Throughout all the studies, each subject was quiet, without movement, with eyes open and ears unplugged, exposed only to ambient room light and sound. For the entire group, whole brain mean CMRglu was 26.1 +/- 6.1 mumol 100 g-1 min-1 (mean +/- SD, n = 40). At age 78, mean CMRglu was, on the average, 26% less than at age 18, an alteration of the same order as the variance among subjects at any age. The gradual decline of mean CMRglu with advancing age occurred at a faster rate than was reported for mean cerebral oxygen utilization, possibly due to increasingly altered pathways for glucose utilization, or to increasing oxidation of ketone bodies or other alternative substrates. Glucose utilization in the hemispheres was symmetrical and mean CMRglu of overall cortex, caudate, and thalamus was equal in individuals at all ages. The slopes of decline with age were similar when LCMRglu was averaged over zones corresponding to centrum semiovale, caudate, putamen, and frontal, temporal, parietal, occipital, and primary visual cortex. However, the metabolic ratio of superior frontal cortex to superior parietal cortex declined with age, possibly due to selective degeneration of superior frontal cortex or to differences between age groups in the sensory and cognitive response to the study. These results should be useful in distinguishing age from disease effects when the FDG scan method is used.

Adolescent↗
PubMed1981

Age differences in nonverbal memory tasks.

Age significantly predicted performances of 120 volunteers, 20 to 84 years old, on six memory tests using visual, auditory, or tactile items which clearly defied verbal labeling. Low scores of persons in the sixth and seventh decade of life were responsible for the age effect. Age accounted for differences in recognition and in reproduction performances over and above the impact shared with a person's performances on the WAIS Block Design and Vocabulary tests. Neither decision criteria, derived from signal detection measures, nor Vocabulary scores differed across six age groups. The progressively lower recognition d' scores across the six age decades suggested that nonverbal memory processing through all three modalities was affected adversely by age.

Adult↗
PubMed1981

Specific memory deficits associated with prolonged alcohol abuse.

The relationship between age, education, length and amount of heavy drinking, and performance on five memory tasks was investigated in 54 chronic alcoholics and 18 age-matched controls. Alcoholics with less than 12 yr of heavy drinking differed reliably from long-term (13-22 yr) and extended long-term drinkers (greater than 23 yr) in recognition memory for visual patterns when scores were corrected for age. Compared with controls, both groups of long-term drinkers were deficient on the visual, auditory, and Faces recognition tests. Age and education of alcoholics accounted for part of performance differences; length of alcohol abuse, however, predicted reliably the decline in memory scores on all but the tactual test. The profile of memory performances seemed to decrease linearly with increasing age and length of alcohol abuse.

Adult↗
PubMed1981

Aged and error differences on Memory-for-Designs.

Age reliably predicted performance of 120 volunteers, 20 to 84 yr. old, on the Memory-for-Designs test. Scoring employed both the Graham-Kendall and a modified scoring technique in which each of 15 designs was rated within six error categories (reversal, distortion, omission, rotation, embellishment, perseveration). Inter-rater reliability of four raters indicated a marked scoring consistency and the error category scoring interacted with age, i.e., older persons (greater than 60 yr.) made more omission and distortion errors than younger persons (less than 40 yr.) who committed proportionally more reversal errors. Concomitant performance on the WAIS Block Design accounted for only part of the age differences in errors. The error category scoring was more sensitive to age differences in visual memory than the usual Graham-Kendall scoring method. In addition, it provided much needed age norms.

Adult↗