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D-13.01 EXPERIMENTAL STUDIES ON BRAIN DAMAGE DUE TO HYPEROSMOLALITY. A. Yasuhara, H. NaitO, Y. Tachibana, T. Suqimoto, T. Mathumura and M. Yasuhara (Moriguchi, Japan)
larger than those of A, and the amplitudes of A were larger than those of F!. These changes were statistically significant (P < 0.01). B-5.08 POLYGRAPHIC STUDY OF RESPONSIVENESS DISTURBANCES IP! PATIENTS WITH EPILEPTOGENIC CERER. Rogozea and V. Florea-Ciocoiu BRAL TUHOURS. (Bucharest, Romania)
The relation in intracranial hemorrhage to hyperosmolatityin the newborn infant has come to be a clinical problem. In the present study, the effect of hyperosmolality on the central nervous system of the rabbit was examined electroHyperosmolality was induced physiologically. in rabbits weiahing 1.5 - 2.0 kg by continuous intravenous injection of hypertonic solutions, such as 7% sodium bicarbonate, 4.64% sodium chloride, 20% glucose and 20% mannitol and the injection lasted up to the death of the animal. Intracranial hemorrhage was regularly induced by injection of any of these solutions, when the plasma osmolality became higher than 400 mOsm/l, suggesting that intracranial hemorIn hyrhaqe is related to hyperosmolality. perosmolalityinduced by'7% sodium bicarbonate, the arousal reaction threshold rose sharply when the olasma osmolalitv exceeded 320 mOsm/l, suggesting that, clinically, plasma osmolality In adshould be maintained below 320 mOsm/l. dition to the arousal reaction, the spontaneous EEG, afferent evoked potential, evoked muscular discharge, photopalpebral reflex (PPR), evoked eyelid microvibration and H wave were examined. Results similar to those seen in the arousal reaction were obtained in the H wave and late PPR component. This suggests that the H wave and late PPR component may be good targets for the evaluation of consciousness levels. The finding with solutions other than 7% sodium bicarbonate differed, suggesting a differing mechanism of action.
A polygraphic study of the somatic (EMG), autonomic (finger plethysmogram, pulse, galvanic skin reaction, respiration) and EEG (auditory evoked potentials and EEG blocking reaction) components of the orienting response elicited by an auditory stimulus was performed in 41 patients with epileptogenic cerebral tumours and in 128 matched subjects in three control groups. The study evidenced that the orienting reaction was significantly more intense in patients with epileptogenic cerebral tumours than in control The degree of intensification depensubjects. ded on the topography and size of tumour, on the features of the EEG tracings, as well as on the electro-clinical form, frequency and hisThus, the most marked intory of seizures. crease in the intensity of the orienting reaction was found in patients with temporo-central and large-sized tumours (over 6 cm), in those with fast EEG rhythms of diffuse or focal irritative type EEG abnormalities, as well as in patients with frequent (daily) seizures, with generalized or generalized + partial seizures and with an over three-year seizure history. The responsiveness disturbances noted should be related to the effects induced by the tumour surrounding tissue on the structures involved in the control and integration of sensory messages.
D-II.05 AUDITORY MIDDLE LATENCY RESPONSES UNDER DIFFERENT CONDITIONS. I. Kadobayashi, A. Toyoshima and N. Kato (Kyoto, Japan)
A-11.07 DISTRIBUTION OF REM SLEEP IN TIME ZONE SHIFTS. T. Kitahara, M. Sasaki, H. Tamura, A. Mori, and S. Endo (Tokyo, Japan)
The middle latency components of the auditory evoked response were examined under different conditions. Normal subjects were told to look at numerals presented by a slide projector (Session l), add (Session 2), and multiply (Session 3). Clicks (0.25 msec duration,, 2 kHz) were continuously given to both ears at the rate of lO/sec at 50 dB HL. In each session, 20 different combinations of numbers were oresented for 4 sec. EEG activity was recorded from a silver disc electrode on the right mastoid referred to an electrode on the nose tip. The EEG was amplified (time constant: 0.3 set, high cut: 2 kHz) and stored on FM tape for later analysis. Three hundred responses to clicks during looking at numerals (N), adding (A), and multiplying (M) were averaged by a computer, excluding those that contained artifacts. The middle latency components included two negative peaks (latency: ca. 11 and 17 msec). Both waves changed markedly depending on the condition. The amplitudes of M were
The effects of time zone changes of REM sleep were studied by using polygraphy. On this occasion, chanqes in the amount of REM sleep and its temporal-distribution after west- and.eastward flights were investigated. The sleep of 7 young adult male subjects was polygraphically recorded in TYO to serve as baselines for comThe westbound flight to CPH & FRA parison. which are 8 hours behind TYO (N=3) and the eastbound flight to SF0 & HNL which are 17, 19 hours behind TYO (N=4), were undertaken on separate occasions. Results: 1) There was a significant increase in the amount of REM sleep and a substantial alteration in its temporal distribution within the sleep episodes, with shortened REM latency after the westbound flights (phase delayed). 2) A decrease in the amount of REM sleep and a prolonged REM latency were found after eastbound flights (phase advance). These results provide further evidence for a circadian rhythm of REM sleep, with a maximum propensity