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Sleep patterns in malnutrition: a longitudinal study of anorexic patients
FREE COMMUNICATIONS IN EEG or caudate stimulation were more effective in causing a potentiation than the antidromic stimulation. These findings will be illustrated, and discussed. Relations to behavioral experiments are assumed. It is suggested that the potentiation is a similar nonspecific, cortical effect as the depression.
74.
A sixteen channel wave pattern digitizer.-E. Kaiser, R. Magnusson and I. Petersen (C openhagen, Denmark, and Goteborg, Sweden).
The digitizer is programmed to convert and codify full-wave EEG sections into 14-bit computer words. The routines comprise conversion of fullwave duration to frequency (five bits), indication whether the ratio of the durations in a half-wave pair is outside a preset interval (one bit), classification of the peak-to-peak amplitude in eight classes (three bits), indication of the number of secondary waves in the full wave (three bits), and indication of the presence and polarity of spikes (two bits).
75.
Sleep patterns in malnutrition: a longitudinal study of anorexic patients.-G. W. Fenton and T. M. Elphieke (London, G.B.).
It is a common clinical observation that patients with anorexia nervosa often display sleep disturbance and it has been suggested that this may be related to the malnutrition. The following study was carried out (in collaboration with P. B. C. Fenwick) in order to investigate these observations. Six patients in the Maudsley Hospital metabolic unit suffering from anorexia nervosa were examined longitudinally. All night sleep EEG recordings were performed in the ward on four consecutive nights within ten to fourteen days of admission and the same procedure was repeated when the patients had gained their o p t i m u m weight six to eight weeks later. The treatment consisted of refeeding only, no psychotropic drugs being used. Two patients received hypnotics, the doses being maintained unchanged throughout the study. Daily ratings of mood and behavior were recorded throughout their stay in hospital. Five of the patients responded well to treatment, each gaining at least 10Kg; one failed to show an appreciable weight change. All the.recordings were performed by a single investigator, who also rated the depth of sleep for each 20-sec period using the Loomis classification. These alphabetic ratings were converted into numerical data to facilitate processing, put on punched tape and analysed by digital computer. The subjects who gained weight displayed changes in their sleep pattern, significantly more time being spent awake and in stage A
681
before treatment while after weight gain the duration of deep sleep (stage D and E) were increased. A significant increase in REM sleep time was also observed on refeeding. The length of time from retiring for the night to first onset of stage C was reduced on retest. The latency of onset of REM appeared to be delayed initially but was significantly less after weight gain. Data concerning changes in sleep pattern throughout each hour of the night were collected and will be presented. No consistent association between change in sleep pattern and alteration in mood could be detected. The patient whose weight remained essentially unchanged did not show any alteration in sleep pattern. These findings confirm the importance of regarding malnutrition and loss of weight as variables which may influence the pattern of an individual's sleep.
76.
Contrasting reactions of the evoked auditory response and amplitude histogram to mental arithmetic and eye opening in man.-A. Glass (Birmingham, G.B.).
In earlier studies, the separate and combined effects on the total amplitude histogram (AH) of the EEG of mental arithmetic and eye opening were compared. Visual evoked responses are known to be reduced in amplitude during mental arithmetic, so it was decided to compare the effects of the two main factors, eye opening and calculation, on the overall amplitude of the evoked response to an auditory stimulus (AER). The EEG was recorded by a Beckman Dynograph in conjunction with an Ampex tape recorder. A trigger pulse was also recorded. Silver disc electrodes were placed at Pz, C3, C4 and P3, P4 positions on the scalp with a reference on the right mastoid. Responses were averaged to a 1000 c/sec tone lasting 150 msec with rise and fall times of 20 msec approximately. The repetition rate of tone was 1 / 2 . 7 - 3 sec. Sixty-four sweeps were averaged by the Biomac 1000 computer both on and off-line. The subject sat in a sound-isolated chamber. As before with the AHs, the AERs (and AHs) were recorded with eyes closed; eyes closed during mental arithmetic (continuous subtraction of 7's); eyes open; eyes open during mental arithmetic. Any possible order effect was balanced out by the design of the experiment. With the AER there was little difference in peak-to-peak amplitude whether eyes were open or shut. Continuous subtraction of 7's reduced the peak-to-peak amplitude by up to 50%. This occurred with eyes open or shut, in contrast to the results of AH measures. It is suggested that this evidence on amplitudes supports the view that the AER is subserved
74.
A sixteen channel wave pattern digitizer.-E. Kaiser, R. Magnusson and I. Petersen (C openhagen, Denmark, and Goteborg, Sweden).
The digitizer is programmed to convert and codify full-wave EEG sections into 14-bit computer words. The routines comprise conversion of fullwave duration to frequency (five bits), indication whether the ratio of the durations in a half-wave pair is outside a preset interval (one bit), classification of the peak-to-peak amplitude in eight classes (three bits), indication of the number of secondary waves in the full wave (three bits), and indication of the presence and polarity of spikes (two bits).
75.
Sleep patterns in malnutrition: a longitudinal study of anorexic patients.-G. W. Fenton and T. M. Elphieke (London, G.B.).
It is a common clinical observation that patients with anorexia nervosa often display sleep disturbance and it has been suggested that this may be related to the malnutrition. The following study was carried out (in collaboration with P. B. C. Fenwick) in order to investigate these observations. Six patients in the Maudsley Hospital metabolic unit suffering from anorexia nervosa were examined longitudinally. All night sleep EEG recordings were performed in the ward on four consecutive nights within ten to fourteen days of admission and the same procedure was repeated when the patients had gained their o p t i m u m weight six to eight weeks later. The treatment consisted of refeeding only, no psychotropic drugs being used. Two patients received hypnotics, the doses being maintained unchanged throughout the study. Daily ratings of mood and behavior were recorded throughout their stay in hospital. Five of the patients responded well to treatment, each gaining at least 10Kg; one failed to show an appreciable weight change. All the.recordings were performed by a single investigator, who also rated the depth of sleep for each 20-sec period using the Loomis classification. These alphabetic ratings were converted into numerical data to facilitate processing, put on punched tape and analysed by digital computer. The subjects who gained weight displayed changes in their sleep pattern, significantly more time being spent awake and in stage A
681
before treatment while after weight gain the duration of deep sleep (stage D and E) were increased. A significant increase in REM sleep time was also observed on refeeding. The length of time from retiring for the night to first onset of stage C was reduced on retest. The latency of onset of REM appeared to be delayed initially but was significantly less after weight gain. Data concerning changes in sleep pattern throughout each hour of the night were collected and will be presented. No consistent association between change in sleep pattern and alteration in mood could be detected. The patient whose weight remained essentially unchanged did not show any alteration in sleep pattern. These findings confirm the importance of regarding malnutrition and loss of weight as variables which may influence the pattern of an individual's sleep.
76.
Contrasting reactions of the evoked auditory response and amplitude histogram to mental arithmetic and eye opening in man.-A. Glass (Birmingham, G.B.).
In earlier studies, the separate and combined effects on the total amplitude histogram (AH) of the EEG of mental arithmetic and eye opening were compared. Visual evoked responses are known to be reduced in amplitude during mental arithmetic, so it was decided to compare the effects of the two main factors, eye opening and calculation, on the overall amplitude of the evoked response to an auditory stimulus (AER). The EEG was recorded by a Beckman Dynograph in conjunction with an Ampex tape recorder. A trigger pulse was also recorded. Silver disc electrodes were placed at Pz, C3, C4 and P3, P4 positions on the scalp with a reference on the right mastoid. Responses were averaged to a 1000 c/sec tone lasting 150 msec with rise and fall times of 20 msec approximately. The repetition rate of tone was 1 / 2 . 7 - 3 sec. Sixty-four sweeps were averaged by the Biomac 1000 computer both on and off-line. The subject sat in a sound-isolated chamber. As before with the AHs, the AERs (and AHs) were recorded with eyes closed; eyes closed during mental arithmetic (continuous subtraction of 7's); eyes open; eyes open during mental arithmetic. Any possible order effect was balanced out by the design of the experiment. With the AER there was little difference in peak-to-peak amplitude whether eyes were open or shut. Continuous subtraction of 7's reduced the peak-to-peak amplitude by up to 50%. This occurred with eyes open or shut, in contrast to the results of AH measures. It is suggested that this evidence on amplitudes supports the view that the AER is subserved