246
Proc. roy. Soc. Med. Volume 68 April 1975
Professor A C Dornhorst (Medical Unit, St George's Hospital, London SWI) A Prospective View
There has been agreement among the speakers on the broad outline of interaction of anoxic and capnaeic drives. However, there have been interesting disagreements, as for instance between Dr Cunningham and Dr Weil, over the immediate response to high altitude. When experienced workers get conflicting results the explanation usually lies in some unconsidered difference in technique, and indeed breathing is very liable to be so influenced. Although a uniform pattern of response to the chemical stimuli can be established, there is a surprisingly great variation in the vigour of response among normal individuals. One of the baffling problems in respiratory medicine is why
16 some patients with airways obstruction hypoventilate and develop anoxic cor pulmonale, while others, perhaps with greater obstruction, do not. The variability among normal subjects means that the hypothesis that the outcome in disease is determined by the premorbid constitution must be taken seriously, though it does not easily explain the negative association of hypoventilation and emphysema. One clinical fact that has not been discussed here is that patients with increased work-cost of breathing often hyperventilate, and this is true not only of acute states like asthma and left ventricular failure, but also of primary emphysema and sclerosing alveolitis. This behaviour contrasts strongly with the effects of adding external loads, and reminds us that abnormal afferent impulses from lungs and airways can contribute to ventilatory drive in disease. A deficiency in this mechanism is thus another possible factor in the genesis of anoxic cor pulmonale.
Meeting 18 November 1974
Work in Progress The Place of EEG Telemetry and Closed-circuit Television in the Diagnosis and Management of Epileptic Patients
telemetry room buffer
amplif iers
by A N Bowden MB MRCP, P Fitch MSC, Professor R W Gilliatt DM FRCP and R G Willison DM FRCPEd (Institute of Neurology, National Hospital, Queen Square, London WC]) The development of EEG telemetry over the past two decades has provided a valuable technique for the study of epileptic patients (Stevens et al. 1971, Ives et al. 1973, Sato et al. 1973, Geier et al. 1974). The earlier literature has been reviewed by Porter et al. (1971). A research programme supported by the Department of Health and Social Security has been set up at the National Hospital,- Queen Square, in which patients with epilepsy or with suspected epilepsy are observed over relatively long periods of time, using EEG telemetry and closed-circuit television. This has been a combined enterprise involving both the University Department of Clinical Neurology and the Hospital Department of Clinical Neurophysiology.
receiver
TVcamera 1
8 EEG channels
_
time code generator
TVcamera2
11 2130
TV monitor
vision mixer
EEG display
video number
generator
cable link to lob
Fig 1 Black diagram of system in telemetry room on wardfloor
17
Section of Measurement in Medicine recording laboratory 8 EEG channels
E:
2f47
Table I Proportion of epileptic patients showing discharges during recording No. of No. in whom epileptic patients discharges recorded 75 31
Preliminary routine recording in EEG Department (mean duration 20 min) Long recording with 75 telemetry and television (mean duration 300 min) coble link from telemetry room
Fig 2 Block diagram ofsystem in basement recording laboratory
A recording room on the ward floor has been set aside in which a patient can be under continuous observation by closed-circuit television for 4-6 hours. During this time the EEG is also monitored, using a small 8-channel transmitter (Datel Inc, Florida, USA, supplied by SLE, Croydon) pinned to the patient's shirt or carried in the pocket. The aerial and receiver are in the same room as the patient (Fig 1) and the amplified EEG and television signals are passed through a cable to a laboratory in the basement where the EEG is recorded on a 14-channel FM taperecorder, additional channels being used for real time and speech (Fig 2). Four channels of EEG are also recorded on a memory monitor (SEM 434, SE Labs (EMI) Ltd) and viewed by the second television camera shown in Fig 1. The picture is then mixed with that of the patient on a split screen which also shows real time (Fig 3). Observation and recording are started in midmorning and continued during lunch, which is followed by a period of post-prandial sleep. An infra-red television camera is used so that the room can be darkened to encourage natural sleep. The main advantages of the technique are as follows:
66
(2) Since the television picture of the patient and four channels of EEG are stored on videotape, the sequence of an attack can be reexamined at leisure. In this way, extra details can be observed which would not have been obvious when the attack originally occurred. (3) Since real time is displayed on the television picture, the full 8-channel EEG for a period covering a clinical attack can be obtained from the FM tape-recorder afterwards and written out on paper in the conventional way. Unless positive phenomena are seen, no bulky paper records need be kept. In the case of 'difficult' epileptics whose management presents special problems, we have found the technique particularly useful in answering the following questions: (1) Are the patient's attacks epileptic or not ? (2) Are the attacks associated with focal or generalized EEG discharges ? (3) Are there specific factors which precipitate clinical attacks or discharges in the EEG? For teaching or record purposes cine-films can be made from videotapes, using an Arriflex camera with a continuously variable frame speed to allow synchronization with the television picture.
(1) When the patient is allowed to relax comfortably, to eat and to sleep, more EEG abof television display; it shows a normalities and clinical attacks occur than in the Fig 3 Photograph at the onset ofa petit-mal seizure while eating. artificial conditions of a conventional EEG patient The digital clock (bottom right) gives the time of the recording session (Table 1). attack
248
Proc. roy. Soc. Med. Volume 68 April 1975
Acknowledgments: We are most grateful to Mrs Carolyn Jacobson and Mr A H Prentice for technical assistance. The work has been supported by grants from the Department of Health and Social Security, the Goldsmiths' Company, Latymer School and the Victoria Butler Fund. REFERENCES Geier S, Bancaud J, Talairach J & Enjelvin M (1974) Electroencephalography and Clinical Neurophysiology 37, 89 Ives J R, Thompson C J & Woods J F (1973) Ekctroencephalography and Clinical Neurophysiology 34, 665 Porter R J, Wolf A A & Penry J K (1971) Amerean Journal ofEEG Technology 11, 145 Sato S, Dreifus F E & Penry J K (1973) Neurology 23. 1335 Stevens J R. Kodama H, Lonsbury B & Mills L 1971) Ekctroencephalography and Clinical Neurophyalology 31, 313
18 Evaluation of Use of ""I1n-labelled Bleomycin in Investigation of Squamous Cell Neoplasia Dr I E Burton, Dr J Todd and Dr R L Turner (Postgraduate School of Studies in Medical and Surgical Sciences, Bradford, BD7 1DP)
Development ofa Chronic Animal Preparation for Pharmacological Research Dr M R Cross, Dr C Weller and Dr E B Raftery (Clinical Research Centre, Harrow, HAI 3UJ)
Meeting 14 June 1974 A visit was made to Imperial Chemical Industries Ltd, Pharmaceutical Division, Macclesfield. Papers were read and a cardiovascular demonstration was given.
The following papers were also read: A Vibrating and Force Measuring Cervical Dilator Dr M M Black, Dr D H Melcher, Mr H A H Melville and Mr J Morgon (University ofSussex and Brighton Area Health Authority)
Continuous Flow Method for Calibrating and Electron Capture Halogen Detector Dr ID W Bethune (Papworth Hospital, Cambridge, CB3 8RE)
Reproducibility of Transcutaneous Aortovelography Dr C B Frazer (Brompton Hospital, London SW3), Dr A E Buchthal, Dr M J R Healy, Dr L H Light and Dr E A Shineboume
Pilot Assessment of Transcutaneous Aortovelography Dr Gillian C Hanson, Dr A R Peisach and Dr Anna E Buchtal (Whipps Cross Hospital, London EllJJ WR) Measurement of Weight Change in Groups of Children Dr N M Cohen, Dr A D Clayden (Department of Community Health, University ofNottingham) and Dr B King (St James' Hospital, Lesotho, Southern Africa)
Measurement of Ataxia Dr B M Wright (Clinical Research Centre, Harrow, HA] 3UJ)
Meeting 18 October 1974 with Section ofRadiology The following papers were read:
Colour Reconstruction Imaging in the Analysis of Serial Angiograms Dr B S Worthington (General Hospital, Nottingham, NG] 6HA)
Reading Chest X-rays for Pneumoconiosis by Computer Dr Keith A Paton (Division ofMedical Computing Clinical Research Centre, Harrow, HAI 3UJ)
Diagnostic X-ray Beam Quality with Special Reference to 350kV Chest Radiography Dr G M Ardran (Nuffield Institute for Medical Research, Oxford; Environmental and Medical Sciences Division, AERE, Harwell) REFERENCE Ardran G M & Crooks H E (1974) Radiography40
Computerized Transverse Axial Scanning Tomography Mr G N Hounsfield (EMI Central Research Laboratories, Schoenberg House, Trevor Road, Hayes, UB3 IHH) (see British Journal of Radiology, 1973, 46, 1016-1022) Practical Experience with the EMI Scanner Dr Jeffrey Gawler (National Hospital, Queen Square, London WC1) REFERENCE Gawler J, DuBoulay G H, BuU J W D & Marshall J (1974) Lancet ii, 419-423
Proc. roy. Soc. Med. Volume 68 April 1975
Professor A C Dornhorst (Medical Unit, St George's Hospital, London SWI) A Prospective View
There has been agreement among the speakers on the broad outline of interaction of anoxic and capnaeic drives. However, there have been interesting disagreements, as for instance between Dr Cunningham and Dr Weil, over the immediate response to high altitude. When experienced workers get conflicting results the explanation usually lies in some unconsidered difference in technique, and indeed breathing is very liable to be so influenced. Although a uniform pattern of response to the chemical stimuli can be established, there is a surprisingly great variation in the vigour of response among normal individuals. One of the baffling problems in respiratory medicine is why
16 some patients with airways obstruction hypoventilate and develop anoxic cor pulmonale, while others, perhaps with greater obstruction, do not. The variability among normal subjects means that the hypothesis that the outcome in disease is determined by the premorbid constitution must be taken seriously, though it does not easily explain the negative association of hypoventilation and emphysema. One clinical fact that has not been discussed here is that patients with increased work-cost of breathing often hyperventilate, and this is true not only of acute states like asthma and left ventricular failure, but also of primary emphysema and sclerosing alveolitis. This behaviour contrasts strongly with the effects of adding external loads, and reminds us that abnormal afferent impulses from lungs and airways can contribute to ventilatory drive in disease. A deficiency in this mechanism is thus another possible factor in the genesis of anoxic cor pulmonale.
Meeting 18 November 1974
Work in Progress The Place of EEG Telemetry and Closed-circuit Television in the Diagnosis and Management of Epileptic Patients
telemetry room buffer
amplif iers
by A N Bowden MB MRCP, P Fitch MSC, Professor R W Gilliatt DM FRCP and R G Willison DM FRCPEd (Institute of Neurology, National Hospital, Queen Square, London WC]) The development of EEG telemetry over the past two decades has provided a valuable technique for the study of epileptic patients (Stevens et al. 1971, Ives et al. 1973, Sato et al. 1973, Geier et al. 1974). The earlier literature has been reviewed by Porter et al. (1971). A research programme supported by the Department of Health and Social Security has been set up at the National Hospital,- Queen Square, in which patients with epilepsy or with suspected epilepsy are observed over relatively long periods of time, using EEG telemetry and closed-circuit television. This has been a combined enterprise involving both the University Department of Clinical Neurology and the Hospital Department of Clinical Neurophysiology.
receiver
TVcamera 1
8 EEG channels
_
time code generator
TVcamera2
11 2130
TV monitor
vision mixer
EEG display
video number
generator
cable link to lob
Fig 1 Black diagram of system in telemetry room on wardfloor
17
Section of Measurement in Medicine recording laboratory 8 EEG channels
E:
2f47
Table I Proportion of epileptic patients showing discharges during recording No. of No. in whom epileptic patients discharges recorded 75 31
Preliminary routine recording in EEG Department (mean duration 20 min) Long recording with 75 telemetry and television (mean duration 300 min) coble link from telemetry room
Fig 2 Block diagram ofsystem in basement recording laboratory
A recording room on the ward floor has been set aside in which a patient can be under continuous observation by closed-circuit television for 4-6 hours. During this time the EEG is also monitored, using a small 8-channel transmitter (Datel Inc, Florida, USA, supplied by SLE, Croydon) pinned to the patient's shirt or carried in the pocket. The aerial and receiver are in the same room as the patient (Fig 1) and the amplified EEG and television signals are passed through a cable to a laboratory in the basement where the EEG is recorded on a 14-channel FM taperecorder, additional channels being used for real time and speech (Fig 2). Four channels of EEG are also recorded on a memory monitor (SEM 434, SE Labs (EMI) Ltd) and viewed by the second television camera shown in Fig 1. The picture is then mixed with that of the patient on a split screen which also shows real time (Fig 3). Observation and recording are started in midmorning and continued during lunch, which is followed by a period of post-prandial sleep. An infra-red television camera is used so that the room can be darkened to encourage natural sleep. The main advantages of the technique are as follows:
66
(2) Since the television picture of the patient and four channels of EEG are stored on videotape, the sequence of an attack can be reexamined at leisure. In this way, extra details can be observed which would not have been obvious when the attack originally occurred. (3) Since real time is displayed on the television picture, the full 8-channel EEG for a period covering a clinical attack can be obtained from the FM tape-recorder afterwards and written out on paper in the conventional way. Unless positive phenomena are seen, no bulky paper records need be kept. In the case of 'difficult' epileptics whose management presents special problems, we have found the technique particularly useful in answering the following questions: (1) Are the patient's attacks epileptic or not ? (2) Are the attacks associated with focal or generalized EEG discharges ? (3) Are there specific factors which precipitate clinical attacks or discharges in the EEG? For teaching or record purposes cine-films can be made from videotapes, using an Arriflex camera with a continuously variable frame speed to allow synchronization with the television picture.
(1) When the patient is allowed to relax comfortably, to eat and to sleep, more EEG abof television display; it shows a normalities and clinical attacks occur than in the Fig 3 Photograph at the onset ofa petit-mal seizure while eating. artificial conditions of a conventional EEG patient The digital clock (bottom right) gives the time of the recording session (Table 1). attack
248
Proc. roy. Soc. Med. Volume 68 April 1975
Acknowledgments: We are most grateful to Mrs Carolyn Jacobson and Mr A H Prentice for technical assistance. The work has been supported by grants from the Department of Health and Social Security, the Goldsmiths' Company, Latymer School and the Victoria Butler Fund. REFERENCES Geier S, Bancaud J, Talairach J & Enjelvin M (1974) Electroencephalography and Clinical Neurophysiology 37, 89 Ives J R, Thompson C J & Woods J F (1973) Ekctroencephalography and Clinical Neurophysiology 34, 665 Porter R J, Wolf A A & Penry J K (1971) Amerean Journal ofEEG Technology 11, 145 Sato S, Dreifus F E & Penry J K (1973) Neurology 23. 1335 Stevens J R. Kodama H, Lonsbury B & Mills L 1971) Ekctroencephalography and Clinical Neurophyalology 31, 313
18 Evaluation of Use of ""I1n-labelled Bleomycin in Investigation of Squamous Cell Neoplasia Dr I E Burton, Dr J Todd and Dr R L Turner (Postgraduate School of Studies in Medical and Surgical Sciences, Bradford, BD7 1DP)
Development ofa Chronic Animal Preparation for Pharmacological Research Dr M R Cross, Dr C Weller and Dr E B Raftery (Clinical Research Centre, Harrow, HAI 3UJ)
Meeting 14 June 1974 A visit was made to Imperial Chemical Industries Ltd, Pharmaceutical Division, Macclesfield. Papers were read and a cardiovascular demonstration was given.
The following papers were also read: A Vibrating and Force Measuring Cervical Dilator Dr M M Black, Dr D H Melcher, Mr H A H Melville and Mr J Morgon (University ofSussex and Brighton Area Health Authority)
Continuous Flow Method for Calibrating and Electron Capture Halogen Detector Dr ID W Bethune (Papworth Hospital, Cambridge, CB3 8RE)
Reproducibility of Transcutaneous Aortovelography Dr C B Frazer (Brompton Hospital, London SW3), Dr A E Buchthal, Dr M J R Healy, Dr L H Light and Dr E A Shineboume
Pilot Assessment of Transcutaneous Aortovelography Dr Gillian C Hanson, Dr A R Peisach and Dr Anna E Buchtal (Whipps Cross Hospital, London EllJJ WR) Measurement of Weight Change in Groups of Children Dr N M Cohen, Dr A D Clayden (Department of Community Health, University ofNottingham) and Dr B King (St James' Hospital, Lesotho, Southern Africa)
Measurement of Ataxia Dr B M Wright (Clinical Research Centre, Harrow, HA] 3UJ)
Meeting 18 October 1974 with Section ofRadiology The following papers were read:
Colour Reconstruction Imaging in the Analysis of Serial Angiograms Dr B S Worthington (General Hospital, Nottingham, NG] 6HA)
Reading Chest X-rays for Pneumoconiosis by Computer Dr Keith A Paton (Division ofMedical Computing Clinical Research Centre, Harrow, HAI 3UJ)
Diagnostic X-ray Beam Quality with Special Reference to 350kV Chest Radiography Dr G M Ardran (Nuffield Institute for Medical Research, Oxford; Environmental and Medical Sciences Division, AERE, Harwell) REFERENCE Ardran G M & Crooks H E (1974) Radiography40
Computerized Transverse Axial Scanning Tomography Mr G N Hounsfield (EMI Central Research Laboratories, Schoenberg House, Trevor Road, Hayes, UB3 IHH) (see British Journal of Radiology, 1973, 46, 1016-1022) Practical Experience with the EMI Scanner Dr Jeffrey Gawler (National Hospital, Queen Square, London WC1) REFERENCE Gawler J, DuBoulay G H, BuU J W D & Marshall J (1974) Lancet ii, 419-423
