37 TABLE II-EFFECTS OF STORAGE AT
40c
ON G.A.D. ACTIVITY
be an effective method of management when surgery is not feasible. Like other laboratory investigations the test of C.S.F7 removal is not infallible especially when negative. Also symptoms fluctuate naturally and neurological assessment must take this into consideration. There may be a critical ventricular size, and at the Massachusetts General Hospital in all patients with normal pressure hydrocephalus who were improved by shunting, the ventricular span was more than 53 mm (by pneumoencephalography
equivalent). preoperative resting C.S.F. pressure may help in interpretation, and in all of our effectively shunted patients it was or
The
Results as mean+s.D. in mot/g/h.
greater than 105 mm of c.s.F. deaths it
unlikely that the reduction in G.A.D. activities observed by these workers is attributable to medication. We suggest rather that where brains of schizophrenic patients are collected from a number of distant mental hospitals while controls are collected from a local district general hospital there is always a possibility of a systematic bias in the circumstances of collection (e.g., in time before removal of the body to the mortuary refrigerator or time from removal of the brain to deep freezing) which may be reflected in neurochemical seems
changes. On the basis of our recent findings (table I) we conclude that neither the deficit in-G.A.D. activity nor the increase in dopamine concentration reported by the Cambridge workers is likely to be related to the schizophrenic disease process. Bird et al. considered the possibility that increase in dopamine might be attributable to drug therapy, a conclusion with which we agree, but we suggest that there must be another explanation for the reduction observed in the activity of G.A.D.
T. J. CROW F. OWEN Division of Psychiatry, Clinical Research Centre, Harrow, Middlesex HA13UJ
A. J. CROSS R. LOFTHOUSE A. LONGDEN
COMMUNICATING HYDROCEPHALUS
SIR,-To your excellent editorial (Nov. 12, p. 1011) I offer four practical additions. In my review of 27 hydrocephalic patients who underwent shunting, 16 were improved and 11 were not.Of the 16 who improved, a disturbance- of gait preceded mental change in 12 and was concomitant in 3. Of the 11 failures mental change came first in 9. Evidently a disturbance of gait is the cardinal feature of symptomatic normal-pressure hydrocephalus and precedes and exceeds mental change. A test removal of 20-30 ml cerebrospinal fluid (c.s.F.) may be useful in diagnosis and as a guide in management, but in 5 patients it also induced much clinical improvement. All were males and only one was demented. One patient, aged 74, with a ventricular span of 60 mm (by pneumoencephalography), was unable to turn over in bed or sit up. In 48 h he was able to take steps unaided. Another patient, aged 74 (ventricular span 64 mm) had severe ataxia of gait which improved in 36 h. A third patient, aged 62 (ventricular span 58 mm) was ataxic and demented but returned to 80% normal in 6 days. The fourth patient, aged 89 (ventricular span 72 mm) was bedridden because of imbalance; in 48 h he could walk unaided. Patient 5, aged 78, ventricular span 60 mm, was bedridden because of imbalance. In 48 h, he was able to take steps unaided.
Hydrocephalus nowadays is discovered by computerised tomography and when the simple test of c.s.F. removal is positive, other laboratory procedures may often be unnecessary. In two patients a second removal of c.s.F. was effective when symptoms recurred. In two patients improvement persisted for 5 months without shunting and repeated removal of c.s.F. may 1.
Fisher, C. M. Clin. Neurosurg. 1977, 24, 270.
Department of Neurology, Massachusetts General Hospital, Boston, Massachusetts 02114, U.S.A.
C. MILLER FISHER
LATE EFFECTS OF FEMALE STERILISATION
SIR,-We are interested in the study of hysterectomy after sterilisation by Mr Letchworth and Mr Noble (Oct. 8, p. 768) and in their interpretation of our data on post-sterilisation menstrual-pattern changes. Two methodological points in their study are questionable. The first is their reliance on the woman’s recollection of her presterilisation menstrual pattern compared with her current one, and their assumption that these women and the wives of vasectomised men are similarly able to recall and report menstrual change. The second is their use of hysterectomy as a measure of menstrual dysfunction. This surgical decision is affected by such factors as physician bias, and Noble himself has admitted that the criteria for performing hysterectomy, even as the initial sterilisation procedure, are perhaps more liberal at his institution than at others.’ Letchworth and Noble comment that the "paradoxical changes"-i.e., both increased and decreased menstrual loss-in our study2 "may have confused attempts to demonstrate measured changes in menstrual loss after female sterilisation". On the contrary, we believe that the random pattern of the changes shows that the changes were probably caused by factors other than the sterilisation procedure. 8500 women were followed up after laparoscopic sterilisation by electrocoagulation, the spring-loaded clip, and the tubal ring. Menstrual variables were examined in patients who were not using systemic contraceptives or intrauterine devices immediately before sterilisation (1862 women at 6 months and 720 women at 12 months).2 The women were asked objective questions about their menstrual cycles (length of cycle, duration of flow, amount of flow, and dysmenorrhoea) at the time of sterilisation and again at each of the follow-up contacts. The responses at the follow-up visits were compared with those at sterilisation. Neil et al.3 and others have suggested that methods of fallopian-tube occlusion which cause less disruption of the ovarian blood-supply lead to less disruption of the menstrual cycle. If this were true the changes reported by women who had had clip or ring application would be less frequent and less severe than those reported by women who had had tubal electrocoagulation. The results did not support this
hypothesis. Of the two possible directions of change, one considered disruptive to the patient was reported by a statistically similar proportion of women in each of the occlusion technique groups. A significantly higher proportion of women in the electrocoagulation group than in the clip or ring group reported changes in the various menstrual cycle indices but less disrup1.
Noble, A. D. Discussion session at the workshop on risks, benefits, and controversies in fertility control, sponsored by the Program for Applied
Research on Fertility Regulation, 1977. 2. McCann, M. F., Kessel, E. Paper presented at the 14th annual scientific meeting of the Association of Planned Parenthood Physicians, 1976. Advances in Planned Parenthood (in the press). 3. Neil, J. R., Hammond, G. T., Noble, A. D., Rushton, L., Letchworth, A. T. Lancet, 1975, ii, 699.
40c
ON G.A.D. ACTIVITY
be an effective method of management when surgery is not feasible. Like other laboratory investigations the test of C.S.F7 removal is not infallible especially when negative. Also symptoms fluctuate naturally and neurological assessment must take this into consideration. There may be a critical ventricular size, and at the Massachusetts General Hospital in all patients with normal pressure hydrocephalus who were improved by shunting, the ventricular span was more than 53 mm (by pneumoencephalography
equivalent). preoperative resting C.S.F. pressure may help in interpretation, and in all of our effectively shunted patients it was or
The
Results as mean+s.D. in mot/g/h.
greater than 105 mm of c.s.F. deaths it
unlikely that the reduction in G.A.D. activities observed by these workers is attributable to medication. We suggest rather that where brains of schizophrenic patients are collected from a number of distant mental hospitals while controls are collected from a local district general hospital there is always a possibility of a systematic bias in the circumstances of collection (e.g., in time before removal of the body to the mortuary refrigerator or time from removal of the brain to deep freezing) which may be reflected in neurochemical seems
changes. On the basis of our recent findings (table I) we conclude that neither the deficit in-G.A.D. activity nor the increase in dopamine concentration reported by the Cambridge workers is likely to be related to the schizophrenic disease process. Bird et al. considered the possibility that increase in dopamine might be attributable to drug therapy, a conclusion with which we agree, but we suggest that there must be another explanation for the reduction observed in the activity of G.A.D.
T. J. CROW F. OWEN Division of Psychiatry, Clinical Research Centre, Harrow, Middlesex HA13UJ
A. J. CROSS R. LOFTHOUSE A. LONGDEN
COMMUNICATING HYDROCEPHALUS
SIR,-To your excellent editorial (Nov. 12, p. 1011) I offer four practical additions. In my review of 27 hydrocephalic patients who underwent shunting, 16 were improved and 11 were not.Of the 16 who improved, a disturbance- of gait preceded mental change in 12 and was concomitant in 3. Of the 11 failures mental change came first in 9. Evidently a disturbance of gait is the cardinal feature of symptomatic normal-pressure hydrocephalus and precedes and exceeds mental change. A test removal of 20-30 ml cerebrospinal fluid (c.s.F.) may be useful in diagnosis and as a guide in management, but in 5 patients it also induced much clinical improvement. All were males and only one was demented. One patient, aged 74, with a ventricular span of 60 mm (by pneumoencephalography), was unable to turn over in bed or sit up. In 48 h he was able to take steps unaided. Another patient, aged 74 (ventricular span 64 mm) had severe ataxia of gait which improved in 36 h. A third patient, aged 62 (ventricular span 58 mm) was ataxic and demented but returned to 80% normal in 6 days. The fourth patient, aged 89 (ventricular span 72 mm) was bedridden because of imbalance; in 48 h he could walk unaided. Patient 5, aged 78, ventricular span 60 mm, was bedridden because of imbalance. In 48 h, he was able to take steps unaided.
Hydrocephalus nowadays is discovered by computerised tomography and when the simple test of c.s.F. removal is positive, other laboratory procedures may often be unnecessary. In two patients a second removal of c.s.F. was effective when symptoms recurred. In two patients improvement persisted for 5 months without shunting and repeated removal of c.s.F. may 1.
Fisher, C. M. Clin. Neurosurg. 1977, 24, 270.
Department of Neurology, Massachusetts General Hospital, Boston, Massachusetts 02114, U.S.A.
C. MILLER FISHER
LATE EFFECTS OF FEMALE STERILISATION
SIR,-We are interested in the study of hysterectomy after sterilisation by Mr Letchworth and Mr Noble (Oct. 8, p. 768) and in their interpretation of our data on post-sterilisation menstrual-pattern changes. Two methodological points in their study are questionable. The first is their reliance on the woman’s recollection of her presterilisation menstrual pattern compared with her current one, and their assumption that these women and the wives of vasectomised men are similarly able to recall and report menstrual change. The second is their use of hysterectomy as a measure of menstrual dysfunction. This surgical decision is affected by such factors as physician bias, and Noble himself has admitted that the criteria for performing hysterectomy, even as the initial sterilisation procedure, are perhaps more liberal at his institution than at others.’ Letchworth and Noble comment that the "paradoxical changes"-i.e., both increased and decreased menstrual loss-in our study2 "may have confused attempts to demonstrate measured changes in menstrual loss after female sterilisation". On the contrary, we believe that the random pattern of the changes shows that the changes were probably caused by factors other than the sterilisation procedure. 8500 women were followed up after laparoscopic sterilisation by electrocoagulation, the spring-loaded clip, and the tubal ring. Menstrual variables were examined in patients who were not using systemic contraceptives or intrauterine devices immediately before sterilisation (1862 women at 6 months and 720 women at 12 months).2 The women were asked objective questions about their menstrual cycles (length of cycle, duration of flow, amount of flow, and dysmenorrhoea) at the time of sterilisation and again at each of the follow-up contacts. The responses at the follow-up visits were compared with those at sterilisation. Neil et al.3 and others have suggested that methods of fallopian-tube occlusion which cause less disruption of the ovarian blood-supply lead to less disruption of the menstrual cycle. If this were true the changes reported by women who had had clip or ring application would be less frequent and less severe than those reported by women who had had tubal electrocoagulation. The results did not support this
hypothesis. Of the two possible directions of change, one considered disruptive to the patient was reported by a statistically similar proportion of women in each of the occlusion technique groups. A significantly higher proportion of women in the electrocoagulation group than in the clip or ring group reported changes in the various menstrual cycle indices but less disrup1.
Noble, A. D. Discussion session at the workshop on risks, benefits, and controversies in fertility control, sponsored by the Program for Applied
Research on Fertility Regulation, 1977. 2. McCann, M. F., Kessel, E. Paper presented at the 14th annual scientific meeting of the Association of Planned Parenthood Physicians, 1976. Advances in Planned Parenthood (in the press). 3. Neil, J. R., Hammond, G. T., Noble, A. D., Rushton, L., Letchworth, A. T. Lancet, 1975, ii, 699.
