David H. Ingvar

Abnormalities of cerebral blood flow distribution in patients with chronic schizophrenia.

Twenty patients with chronic schizophrenia were studied, m e younger group (four women and seven men, mean age 25 years) and one older group (nine women, mean age 61 years) with a mean duration of the disease of 5 years and 40 years respectively. All patients showed classical symptoms of schizophrenia with cognitive and emotional disturbances. The younger patients were well preserved intellectually. A11 the older o n e showed advanced deterioration with autism, bizarre behavior, symptoms of catatonia, ongoing hallucinations, etc. Regional cerebral blood flow (rCBF) was measured with the lS8Xenon method in the dominant hemisphere at rest and during attempts at mental activation, using a computer operated 32-detector type of equipment. Both groups showed normal mean rCBF variables. In the older group, and to some extent in the younger one, significant correlations were established between the mean hemisphere flow level and the degree of psychosis (rated with the Rockland and Pollin scale (RP-scale)). The regional rCBF distribution was by and large normal in the younger group with a predominance of high flows in frontal regions. In the older patients, another pattern was found with relatively low flows frontally, and, in many cases, relatively high flows occipito-temporally. This “hypofrontal” rCBF pattern in the deteriorated schizophrenics differed not only from the pattern found in the non-psychotic, neurologically normal reference group but afso from a group of older patients with Alzheimer’s disease. The flow level in occipito-temporal parts of the hemisphere in the schizophrenics correlated positively to the degree of cognitive disturbance rated with the RP-scale. Psychological testing with Raven’s matrices in the younger group gave by and large normal flow augmentations within expected hemisphere regions. In the most autistic older patients, only very slight flow changes, if any at all, were recorded postcentrally in connection with a simple picture test. Some of the older patients with whom contact was established, did, however, show fairly normal rCBF changes during this test. The “hypofrontal” rCBF distribution pattern at a normal flow level found in older deteriorated schizophrenics indicates that an abnormally low level of activity may prevail within the frontal lobe in such patients. Some similarities between the emotional defects, the speech and motor abnormalities seen in chronic schizophrenia, and symptoms found in patients with frontal lobe lesions are pointed out.

Brain structures participating in mental simulation of motor behavior: A neuropsychological interpretation☆

This paper reviews findings from cognitive and sport psychology, as well as from neurophysiology, concerning mental simulation of movement. A neuropsychological hypothesis is advanced to explain why mental practice can improve motor skill learning. Mental practice activates certain brain structures selectively as shown by measurements of regional cerebral blood flow. It appears likely that this activation improves the subsequent control of execution of movements. It is pointed out that the study of simulation of movements may not only be of value for sport training but also have importance for the rehabilitation of patients with motor disturbances following lesions of the central nervous system.

The blood flow of the cerebral cortex determined by radioactive krypton85

Der radioaktive indifferente Luftbestandteil Krypton85 (in Ringer-Flüssigkeit) wird in die Arteria carotis communis injiziert und die Radioaktivität über der freigelegten Gehirnoberfläche verfolgt. Die Methode ergibt reproduzierbare quantitativecorticale Perfusionswerte und eignet sich auch für andere Gewebe.

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.

Motor imagery activates the cerebellum regionally. A SPECT rCBF study with 99mTc-HMPAO.

Our earlier findings of a cerebellar activation during motor imagery (Brain Res., 535 (1990) 313-317) were made with a technique with low regional resolution. Therefore we could not elucidate the distribution of the cerebellar activation. In the present study the cerebellar regional cerebral blood flow (rCBF) changes during motor imagery (MI) was measured with a single photon emission computed tomography (SPECT) rCBF method (99mTc-HMPAO) with higher regional resolution during (1) silent counting, and (2) MI (which included silent counting) in 17 normal subjects. Comparing the SPECT results from the two tasks revealed the regional activations during MI. We confirmed that the most pronounced regional activations during MI were found in the cerebellum, especially in its infero-lateral parts on both sides.

Normal values of regional cerebral blood flow in man, including flow and weight estimates of gray and white matter. A preliminary summary

Seven normal young men (employed by the Fire Brigades of Lund and Malmci) volunteered for the study. None of them had a history of any severe disease or trauma. All were in excellent physical condition. The rCHF studies (double determinations with intracarotid injections of 5 ml isotope solution, about 15 to 20 min. apart) were carried out without prernedication. The position of the injection catheter within the internal carotid artery was checked with saline injections resulting in forehead blanching. During the studies the arterial pC& and the blood pressure was checked. Sone of the subjects had any sequelae of the procedure. For the rCBF measurements a four-channel detector equipment (Manufactured by NUKAB, Gciteborg) was used (Fig. 1). It consisted of a lead collimator block with nine parallel cylindrical holes (diameter 3.5 cm) for the detectors. The holes were set apart so as to cover the side of a human skull. In the present study four standard holes were used, covering “temporal”, “precentral”, “central”, and “postcentral” regions of the hemisphere injected. The central axis of each detector hole was marked on the skull of the subject and a control x-ray was taken in order to relate the measured regions to certain landmarks of the skull bones. Point source measurements (carried out by Mr. G. Suedberg, Department of Medical Radiophysies) showed that the overlap between two adjacent fields of measurement with the present collimator was very small. The efficiency of counting in the

REGIONAL CEREBRAL BLOOD FLOW IN ORGANIC DEMENTIA WITH EARLY ONSET

A few years after the development of the nitrous oxide technique in 1945 by Kety and Schmidt ( l ) , it was established that organic dementia, like other states of impaired function of the central nervous system, is accompanied by a reduction of the total mean cerebral oxygen uptake and blood flow (2 , 3 ) . This was later confirmed with the Lassen-Munck modification of the same method (4), and also by the 13”Xenon clearance method in measurements of the hemisphere flow ( 5 , 6). In bilateral studies it was also shown that the reduction of the cerebral metabolism and blood flow in organic dementia appeared to be most pronounced in the dominant hemisphere, a finding suggesting a “focal” nature of the pathological process underlying organic dementia ( 7 ) . In the investigation presented here, a multi-detector regional cerebral blood flow (rCBF) technique was used to study whether the cerebral circulatory abnormality in organic dementia with early onset is of a diffuse nature, or whether it shows “focal” characteristics related to the psychic symptoms. Another problem which was considered was the relation, if any, between the cerebral blood flow changes and the typical regional distribution of the patho-anatomical changes which are found in presenile dementia of the Alzheimer type (8, 9). This is a first account of the general findings in 38 patients in whom symptoms of dementia had appeared early, i. e. within the fourth or fifth decade. They were referred to one of the three following groups, the Alzheimer group, the “cerebrovascular”group, and a group of other cases (see below). In this paper some general differences between these groups are considered, but the main emphasis is placed on the multi-detector rCBF technique. The clinical part of the study is not yet finished, and it is therefore not possible to include a final discussion of the rCBF data related to the symptomatology,

SPECT measurements with 99mTc-HM-PAO in focal epilepsy.

The ability of SPECT measurements with [99mTc]–HM-PAO (Ceretec) to find the location of the epileptic focus was studied in patients under consideration for neurosurgical treatment for therapy-resistant focal epilepsy. The location of low [99mTc]–HM-PAO uptake regions found at interictal measurements, and of high [99mTc]–HM-PAO uptake regions found at ictal measurements, was compared to the findings of extensive ictal and interictal EEG examinations, and to the results of CT and MRT. While EEG revealed focal epileptic activity in all of the 14 patients, SPECT showed regional abnormalities in 13 (93%). CT and MRT showed abnormal findings in 30%.

Cerebral Complications Following Measurements of Regional Cerebral Blood Flow (rCBF) With the lntra-arterial 133Xenon Injection Method

The rate of complications was studied following measurements of regional cerebral blood flow (rCBF) with the intra-arterial 133Xenon technique. The investigation was based upon reports of rCBF measurements in close to 4,000 patients, carried out at 18 European and American centers. Two fatalities were reported. The overall rate of complication was found to be 1.3% with permanent neurological sequelae in 0.2%.Almost all complications were reported in patients with arterial or intracranial disease. The complication rates found are equal to, or lower than, corresponding rates following cerebral angiography with carotid puncture. Based upon the experiences reported, some factors are enumerated which appear important in order to keep the rate of complication low.

Dyslexia among Swedish prison inmates in relation to neuropsychology and personality.

Several investigations have reported high frequencies of reading and writing disabilities in criminal populations. The aims of the present study were to assess the frequency of dyslexia among Swedish prison inmates and to relate dyslexia to other indices of neuropsychological functions. Sixty-three prison inmates with Swedish as their native language, age 19 to 57 years, were examined by interviews, tests of academic achievement, and neuropsychological assessment. Twenty-six (41%) were diagnosed as dyslexic. As expected, the dyslexic group performed more poorly on verbal tests as compared to the normal readers among the prison inmates, but they also performed more poorly on tests measuring nonverbal abilities. The dyslexic group had higher frequencies of paranoid and avoidant personality disorders compared to the nondyslexics. They also reported higher levels of anxiety and suspicion and a lower degree of socialization. Previous studies report low IQ to be associated with criminal propensity, supporting the interpretation that a double handicap (dyslexia and low IQ) increases the risk of entering a criminal career and remaining in it.