Biomedical subjects
Publications and source records attributed to C Logar.
A method for comparison of EEG mapping findings on the basis of numeric data, i.e. the numeric power values measured at the electrode sites for each frequency band, is described. Examples for the clinical use of comparison studies in epileptic patients are given. The problems regarding methodological issues are discussed.
The value of long-term EEG recordings for diagnosis and differential diagnosis of epilepsy is described. It is emphasized that long-term EEF monitoring increases the scope of EEG techniques and improves the diagnostic value of standard EEG recordings providing up to 90% positive diagnostic information. In particular, the value of ambulatory cassette recording is stressed. Allowing quantification of epileptic activity recorded in real-life situation, useful information not available by means of standard EEG recordings can be obtained. Recording and scoring all-night sleep, it enables studying abnormalities of sleep patterns. In addition the value of long-term EEG recordings in therapy and control of epileptic patients is pointed out and discussed.
The impact of major risk factors for stroke on EEG mapping and routine EEG findings was evaluated in volunteers with no clinical signs of cerebrovascular or other neuropsychiatric disease. Focal changes were seen in 22 subjects (30%) by means of EEG mapping, but in only 12 cases (16%) when routine-EEG was used (p < .05). 4/35 (11%) volunteers without RF had focal changes while this was seen in 18/39 (46%) subjects in whom risk factors (RF) were found (p < .01). An association was seen between the presence of EEG foci and number of RF. 59% of subjects with 2 or 3 RF had focal abnormalities as opposed to 36% of those with 1 RF and 11% of RF free individuals (p < .05). The findings could be confirmed by averaging the EEG data according to the different number of RF revealing statistically significant differences between each of the 3 groups. Using routine EEG alone no significant correlation to the presence or number of RF was found. Our data demonstrate EEG abnormalities in a considerable portion of normal middle aged individuals which in part may be attributed to the presence of RF.
In 62 patients with late onset epilepsy the findings of EEG mapping routine EEG and CT were compared. Forty four patients had generalized, 18 partial seizures. In 39 patients (63%) EEG mapping revealed focal changes but only in 24 patients (39%) using routine EEG alone. Thus the EEG mapping showed focal abnormalities significantly more often and this could be demonstrated in the separated groups of patients with generalized or partial seizures as well. Lesions in CT occurred in 39 patients (63%). The focal abnormalities in EEG mapping were significantly related to the lesions in CT. Moreover focal changes corresponding to CT lesions were obtained by means of EEG mapping in 32 patients (82%) but only in 20 patients (51%) using routine EEG and in that way the EEG mapping could indicate focal lesions in CT significantly more often than routine EEG. Regarding etiology this was especially seen in the group with vascular origin of epilepsy.
In 163 patients with focal cerebral lesions, 43 of them with completed stroke, 43 patients with TIA, 33 patients with ICH and 29 patients with malignant and 15 patients with benign tumors EEG mapping and CT was performed. The results of EEG mapping obtained using automated artifact detection were compared to those achieved by means of visual control of raw EEG. Furthermore the impact of long (850 +/- 250s) or short (32s) analysis time was studied. Eliminating artifacts by means of visual control of raw EEG significantly more positive results were obtained than using automated artifact detection. That was found in patients with as well as in patients without lesions in CT. In relation to etiology a significant difference was found only in cerebrovascular diseases but not in the other patients-groups. Corresponding results were found in 75% of the patients. The visual control provided additional lateralization especially in patients with CS (37%) and TIA (26%). A longer duration of analysed EEG epochs did not increase the number of focal changes in EEG mapping.
33 patients with intracerebral hemorrhage were studied and the findings of EEG mapping, routine EEG and CT were compared. It could be shown, that the EEG mapping revealed in 6 patients additional focal changes corresponding with the clinical signs compared to conventional EEG. Identical results of EEG mapping and CT were found in 27 patients. In 5 patients the focal changes were localised contralateral to the hyperdense lesion in CT, and in 1 patient the EEG mapping failed to show any lateralisation. A negative intercorrelation between the size of the hematoma and the frequency, which revealed the focal signs in EEG mapping, could be shown.
In 148 patients with focal cerebral lesions the findings of EEG mapping, routine EEG and CT were compared. Regarding etiology 43 patients suffered from completed stroke (CS), 43 patients from transient ischemic attack (TIA), 33 patients had an intracerebral hemorrhage (ICH) and 29 an hemispheric tumor. In 37 patients with CS (86%) and 27 patients with TIA (63%) the EEG mapping revealed focal changes, but only in 28 patients with CS (65%) and in 11 patients (26%) with TIA using routine EEG alone. Thus the EEG mapping showed focal abnormalities significantly more often. In the remaining patient groups no significant difference in the results of EEG mapping or routine EEG could be demonstrated. Focal abnormalities corresponding to focal lesions seen in CT were obtained by means of EEG mapping in 27 patients (90%) with CS and 10 patients (77%) with TIA, but only in 17 patients (57%) with CS and 4 patients (31%) with TIA using routine EEG and in that way the EEG mapping could indicate focal lesions in CT significantly more often than routine EEG. In the remaining patient groups no significant difference in the number of focal changes corresponding to lesions in CT could be seen.
70 patients with Completed stroke were studied and the findings of routine EEG, EEG mapping and CT were compared. It could be shown, that the EEG mapping revealed significantly more often focal changes corresponding with the clinical signs (83%) than the routine EEG (57%). Hypodense lesions in CT were seen in 54 patients. Identical results of EEG mapping and CT were found in 50 patients, EEG mapping and routine EEG were identical in 46 patients. The EEG mapping provided additional lateralisation in 12 patients with negative CT findings and in 21 patients with negative routine EEG. In patients with hypodense lesions in CT the EEG mapping revealed significantly more often focal changes (85%) than the routine EEG (59)%).
1. The results of brain mapping had been studied in 27 patients with different stages of ischemic stroke and in 20 patients with dementia, ten of SDAT and ten of vascular type. 2. It has been shown that in ischemic stroke the mapping correlates better with the severity of clinical symptoms than with anatomical and hemodynamic imaging methods. For the differentiation of SDAT and VD the mapping showed a clear cut possibility of differentiation.
The nature and extent of EEG changes in 114 patients with tick-borne encephalitis were reported. The diagnosis was confirmed by the clinical picture, as well as the pathological increase in cells in the liquor and serologically by positive Ig-M titres. EEG findings were compared in patients with or without involvement of the brain. The EEG revealed pathological results in 76 patients, whereby the dominant pathological change was frequently occurring synchronous bursts of generalized slow bilateral waves. 12 patients with involvement of the brain all showed pathological EEG changes, a much higher rate than in the remaining patients and these findings were also more marked. However, 64 patients with clinical evidence of meningitic involvement showed pathological EEG changes, too.
The clinical features, complications and course of barbiturate poisoning are described and illustrated by two case histories in order to recommend therapeutic guidelines on the basis of practical experience. For the intensive care physician it is essential to get information on the composition of barbiturate-containing drugs as rapidly as possible in order to determine the correct therapeutic management. A table is presented of the components of the most commonly used barbiturates.
EEG recordings were carried out on 36 patients with the verified diagnosis of bruxism and unilateral headache. Occlusal splints were applied in the long-term management of these patients. Initial EEG recordings showed pathological changes in 56% of the patients. The EEG recordings were repeated two and six weeks later in these patients and following improvement in the clinical symptomatology pathological EEG patterns were detected in only 22% of all cases. This decrease is of statistical significance.
124 patients with cerebrovascular ischemic disease were studied, 67 of them with irreversible neurological deficits, and the EEG-findings of patients with (50) or without cardiac arrhythmia (74) were compared. Moreover, the EEG-diagnoses of these patients were compared with 40 controls without cerebrovascular ischemic disease. Patients with irreversible neurological deficit had significantly more often cardiac dysrhythmia (51%) than patients with reversible neurological symptoms (28%). In patients with reversible neurological symptoms and in the control group no difference between patients with or without disturbance of the heart rhythm could be found. But in patients with irreversible neurological deficit in presence of cardiac dysrhythmia significantly more pathological EEG-findings could be found with significantly more pronounced EEG changes especially in presence of atrial fibrillation.
EEG-investigations before and after long-term-treatment with occlusal-splints were carried out in 36 bruxism patients suffering from unilateral headache. The results of the latter group were compared to those of 41 patients with classical migraine and to those of a healthy control-group. 20 (56%) of our patients showed pathological EEG-pattern in which focal abnormalities (39%) were dominating. After a long-term-treatment, mentioned before, there was a significant decrease of pathological EEG-pattern combined with a distinct improvement of all clinical symptoms. In patients with classical migraine a higher number of pathological EEG-recordings were seen during attack as well as during interval. Comparing the EEG-findings of bruxism after treatment to those of the healthy controls, no significant differences were found anymore.
Character and extent of changes in EEG in 45 patients with senile dementia of Alzheimer type (SDAT) were reported and the EEG-findings of patients with moderate (18) or severe (27) dementia were compared. The EEG-findings in these patients were compared with a group of 82 patients with multi-infarct dementia (MID). The EEG showed pathological results in 37 patients with predominating general changes (59%). In patients with severe dementia significantly more pathological results especially a significantly slower basic rhythm could be found. The degree of the cerebral atrophy verified by CT did not correspond with character and extent of the changes in EEG. The comparison between patients with SDAT and 82 patients with MID, revealed a significantly more frequent occurrence of unilateral slowing of the basic rhythm but a less frequent occurrence of focal changes. However, there was no significant difference in the number of normal and pathological EEG. The comparison between patients with SDAT and patients with MID without neurological deficit failed to show a significant difference in the number of normal and pathological EEG as well. It could be shown that in patients with severe dementia the EEG revealed significantly more pathological results as well as a significantly slower basic rhythm. However, the EEG could not differentiate between SDAT and MID.
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Eighteen EEG long-term recordings were carried out in patients with generalized fits of different etiologies using a mobile 4-channel monitoring system in order to observe individual patterns of epileptic activity. In patients with idiopathic tonic-clonic seizures (A) no connection of frequency of spike-wave bursts with the sleep-wakefulness cycle was observed. In patients suffering from fits of organic nature (B) a peak of paroxysms was obtained in the hours before sleep onset, whereas in patients with absence seizures (C) a maximum was found in the morning hours after awakening. In patients with idiopathic fits (tonic-clonic and absence seizures) the minimum of bursts was observed in REM sleep, whereas stage 0 (tonic-clonic) and stage 1 (absence) were most prone to discharges. Patients with secondary generalized epilepsy had most spike-wave bursts in deep sleep. In the absence seizure group the transitional periods within the light non-REM-sleep stages were more susceptible to paroxysms than the retained stages. In patients with idiopathic grand mal seizures, the highest frequency of paroxysmal discharges was found during time spent awake in the night when retained over a longer period of time. The group including cases with attacks of organic nature did not show any preference to shifting times or preservation episodes of sleep stages.
In 31 patients with tranquilizer-and 13 patients with drug abuse the character and extent of changes in EEG during withdrawal period were studied and the influence of additional abuse of alcohol or barbiturates was investigated. The EEG showed pathological results in 22 patients (50%). Generalised spike activity was dominant, which was found more often in patients with tranquilizer abuse (35%) than in patients with drug abuse (15%). In patients with abuse of tranquilizers and additional alcoholism pathological EEGs were found more often (65%) than in the remaining patients (36%). Also in patients with additional abuse of barbiturates pathological EEGs (67%) were found more often. In patients with drug abuse with or without additional abuse of alcohol or barbiturates there was no difference between the number of normal and pathological EEGs. In patients with longer persistence of the tranquilizer abuse the number of pathological EEGs increased. Controls of the EEG revealed with increasing time interval an increasing number of normalised EEGs especially in patients without alcoholism of barbiturate abuse. Therefore the EEG revealed functional disturbances in the withdrawal period after abuse of tranquilizers or drugs which were more pronounced in patients with additional abuse or alcohol or barbiturates.