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Biomedical subjects

D H Ingvar

Publications and source records attributed to D H Ingvar.

At least 73 records · Page 4Linked to original sources
PubMed1977

Electroencephalographic changes in the dominant hemisphere during memorizing and reasoning.

The EEG was recorded with bipolar technique in ten normal subjects in the frontal, temporal and occipital regions of the dominant hemisphere in four situations: (1) during an auditory memory test, (2) during 'auditory rest' (listening to white noise), (3) during a visual reasoning test and (4) during 'visual rest' (watching a black dot on a white screen). Computer analysis of the EEG was made by (a) an on-line automatic EEG analyser yielding measures of mean power, mean frequency and frequency spread (complexity) and (b) an off-line period-amplitude (P-A) analysis, which gave per cent activity time and mean voltage in 21 frequency bands. As compared to auditory rest the auditory memory test gave an amplitude increase frontally in the alpha, theta, and delta bands. During the visual reasoning test there was in addition an amplitude increase in the alpha band in the temporal region. During the auditory test a tendency to a decrease of the alpha activity was seen in all three regions but this decrease occurred only occipitally during the visual test. The two types of mental activity thus induced two patterns of regional EEG changes. These showed principal similarities to regional cerebral blood flow patterns which have been recorded during visual and auditory tests of about the same types as those used in the present study.

Auditory Perception↗
PubMed1977

EEG in presenile dementia related to cerebral blood flow and autopsy findings.

EEG, regional cerebral blood flow (rCBF) and neuropathological autopsy data were studied in 17 patients with presenile dementia. RCBF was measured in 14 cases using the intra-arterial-133-Xenon clearance technique. The neuropathological study included semi-serial whole brain microscopical sections in which the severity and regional distribution of the neuronal degeneration was studied, particularly in the cortex and the brain stem. There were two main diagnostic groups, seven cases of Alzheimer's disease and five cases with a cortical atrophy of the Pick (DFT) type. Both groups showed fronto-temporal cortical degeneration. In addition the Alzheimer group showed severe postcentral and posterior-temporal loss of neurons. There were also three cases with degenerative changes, suggesting Jacob-Creutzfeldt's disease. The Alzheimer cases had EEG abnormalities which progressed slowly. In contrast, the Pick (DFT) patients had normal EEGs which remained so even late in the course when the signs of dementia were marked. A positive correlation between rCBF reduction in postcentral areas (as evidence of neuronal loss in these regions) and an increase of EEG abnormality could be established. Degenerative changes confined to frontal and anterior-temporal cortical regions with concomitant flow reduction, on the other hand, appeared to leave the alpha rhythm essentially undisturbed. Finally, the relationship between bifrontal delta-episodes in EEG and neuropathological evidence of brain stem lesions was confirmed.

Age Factors↗
PubMed1977

Cerebral dysfunction in alcoholism and presenile dementia. A comparison of two groups of patients with similar reduction of the cerebral blood flow.

Fifteen chronic alcoholics and 15 presenile patients were matched in pairs with regard to their mean hemisphere cerebral blood parameters-an index of brain metabolism. The distribution of the regional cerebral blood flow was similar in the two groups. The alcoholics performed significantly better in all psychometric tests than the presenile patients and more alcoholics than presenile patients were still employed and working. Nine presenile patients and one alcoholic showed symptoms indicating brain stem dysfunction. The measurements of the cerebral blood blow were made at rest while the psychometric testings and the evaluation of the social performance gave information about the brain at work. It is suggested that cerebral dysfunction in alcoholics to some extent can be partly overcome by brain activation procedures. In contrast, the defects of higher mental functions in presenile dementia cannot be compensated for.

Alcoholism↗
PubMed1976

Functional landscapes of the dominant hemisphere.

There is abundant evidence that in non-anoxic brain tissue the blood flow is controlled mainly by the functional activity of the neurons. This enables the use of regional blood flow measurements for the localization and quantitation of events in the human brain which correlate to normal and abnormal mental activity. Measurements of regional cerebral blood flow (rCBF) by means of the 133Xe clearance technique have been demonstrated that the activity distribution in the normal resting brain shows a typical "landscape", with the highest activities in the premotor and frontal regions and the lowest in temporal and parietal ones. The resting pattern is readily changed by voluntary motor activity which gives a rolandic-postrolandic activity peak and by sensory stimulation which activates rolandic and prerolandic structures especially. Speech and reading activates the upper, anterior and posterior speech cortices, as well as the face, tongue and mouth area. Problem solving also activates premotor and frontal regions especially and, if visual activity is involved, the occipital pole is also activated. These normal patterns confirm by and large well known aspects of the functional anatomy of the human dominant hemisphere.

Blood Pressure↗
PubMed1976

Regional cerebral blood flow in focal cortical epilepsy.

Regional cerebral blood flow (rCBF) was studied in ten patients with focal cortical epilepsy. The blood flow was measured by the intra-arterial injection of xenon 133 (133Xe), and the isotope clearance was recorded by a multidetector scintillation camera with 254 detectors. Three patients were studied both during a seizure and (in the same setting) in the interictal period; six patients were studied only in the interictal period, and one patient was studied only during a seizure. Studies during seizures all showed marked flow increases in areas presumed to participate in the seizure activity. This finding accords with earlier studies. All nine patients studied in the interictal phase showed, either spontaneously or during activation by intermittent light, focal flow increases in areas presumed to comprise the epileptic focus. These interictal hyperemic foci probably reflect subictal neuronal hyperactivity in epileptogenic nervous tissue. Only two of the patients had distinct epileptic electroencephalographic foci. It appears that rCBF studies can be a valuable diagnostic tool in the investigation of cortical epileptogenic lesions.

Adult↗
PubMed1976

Correlation between dominant EEG frequency, cerebral oxygen uptake and blood flow.

In 32 chronic patients the EEG in temporal and occipito-parietal bipolar leads was analyzed with a manual method giving a period frequency index. The cerebral oxygen uptake (CMRO2) was calculated from the arteriovenous oxygen difference between samples from the internal carotid artery and the jugular bulb respectively, and from measurement of cerebral blood flow with the 133Xenon clearance method. A strong correlation (r = 0.78, P less than 0.001) was found between the EEG frequency indices and the CMRO2 of the hemisphere from which the EEG was recorded. Significant correlations between the EEG indices and gray matter cerebral blood flow were also demonstrated, while the correlation between the EEG indices and the blood flow of the white matter was weak. No correlation at all was found between the EEG indices and the relative weight of the gray matter. We conclude that the EEG carries information about the metabolic activity of the brain tissue. The EEG frequency also correlates with the blood flow of the gray matter of the brain when tissue anoxia has not uncoupled the normal function--flow relationship prevailing in the brain.

Adult↗
PubMed1976

Cognitive reduction in presenile dementia related to regional abnormalities of the cerebral blood flow.

Fifty-five patients with presenile dementia were examined. There were 28 women and 27 men, and the mean age was 59 and 56 years respectively at the time of the study. A large series of psychometric tests was used, and with the aid of age-matched non-demented controls five significantly different cognitive reduction groups could be identified. In the demented patients the regional cerebral blood flow (rCBF) was determined with an eight-detector or 32-detector equipment. There was a rough proportionality between the cognitive reduction and a decrease of the cerebral blood flow (especially the flow in the grey matter). In addition, certain regional flow abnormalities correlated with specific cognitive functions in a manner resembling the cognitive defects found in focal brain lesions in the same region. Thus, patients who showed only memory disturbances demonstrated a focal flow reduction in the temporal region. More severely affected patients, with reduction of verbal abilities and signs of agnosia, showed very low flows in occipito-temporo-parietal parts of the hemisphere. The results offer a principal confirmation of the dynamic field theory concerning the functional organization of the cerebral cortex.

Age Factors↗
PubMed1975

Effects of promethazine on nocturnal sleep in normal man.

The effects of a phenothiazine, on sleep in ten healthy volunteers were investigated in two double blind polygraphic studies. The first part consisted of a single dose study with promethazine 50, 100, and 200 mg, using pentobarbital 100 mg as a reference substance. In the second part, four subjects spent 20 consecutive nights with nine drug nights (promethazine 100 mg), followed by a placebo withdrawal period of six nights, in the sleep laboratory. Promethazine showed a dose related REM-depressing effect with a greater decrease, the higher the dose. The placebo value was 20.7% REM of total sleep time and gave 16.3, 13.5 and 11.4 respectively, for promethazine 50, 100 and 200 mg. Pentobarbital gave 16.2% REM. There was also an increase of stage II and with the highest dose an increase of stage III + IV. An increase of REM-latency together with a decrease of REM-periods was also seen, and while pentobarbital gave a decrease in REM-density, promethazine did not cause any changes in the phasic REM-component. A REM-rebound was seen in the first night of withdrawal with an increase of per cent REM from 19.9%-25.1%. The mean for the whole withdrawal period was 23.1%. Promethazine in the highest dose, 200 mg, gave drowsiness and hangover effects in 14 nights out of 20. The REM-depressing effect of promethazine together with its relatively weak REM-rebound effect may explain its value in the treatment of withdrawal symptoms following abuse of alcohol and barbiturates.

Adult↗
PubMed1975

Effects of a new butyrophenone derivate (Buronil) on nocturnal sleep in normal man.

Nocturnal sleep was studied in eight young normal volunteers (3 female and 5 male students) with polygraphic technique during 2 periods of 10 night each. After 2 adaptation and 2 baseline nights with placebo, they were given methylperone (Buronil) 10 or 50 mg per night during three nights and then again placebo for three withdrawal nights. The study was made double blind. The scoring of the records was done according to the manual by Rechtschaffen and Kales (1968). No changes of sleep stages were seen during the drug periods. The lower dose gave an increase of sleep latency but a decrease of number of awakenings during the night. An increase of REM-periods was shown after 50 mg and also a decrease of REM-latency and REM-density. The only significant change during withdrawal periods was a decrease of REM-sleep after methylperone 50 mg, so there was no "barbiturate type" of withdrawal. The change was also different from that of chloropromazine, which has no clear rebound effect.

Adult↗
PubMed1975

Effects of dixyrazine and methaqualone on the sleep pattern in normal man.

Whole night EEG and polygraphic recordings were made in ten young, healthy, male volunteers after dixyrazine (12.5 mg, 25 mg, 50 mg), methaqualone (250 mg) and Isonox (methaqualone 250 mg + etodroxizine 50 mg). A total of 156 recording nights (36 adaptation nights were not included in the analyses) were scored for different sleep stages according to accepted criteria. The smallest dose of dixyrazine (12.5 mg) had no significant effect upon sleep pattern: the larger doses (25 mg and 50 mg) caused significant decreases in REM-sleep during the first nights of administration. The decrease disappeared during the following two nights of treatment. No withdrawal effects were seen. Methaqualone also caused moderate depression of REM-sleep during the first night of treatment, and this effect, too, disappeared during prolonged administration. Isonox (methaqualone + etodroxizine) had a somewhat stronger surpressive effect upon REM-sleep than methaqualone alone.

Adult↗