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The relationship between nocturnal motility and the enuresis alarm device
Psychosomatic Research,
Journal of Printed in Great Britain.
Vol. 30. No.
THE RELATIONSHIP
I, pp. 63-65,
1986
0
BETWEEN NOCTURNAL
THE ENURESIS ALARM
0022-39996036 $3.00 + 0.W 1986 Pergamon Press Ltd.
MOTILITY
AND
DEVICE
A. J. MACAULAY, M. GUPTA, A. H. CRISP and A. V. BHAT (Received 22 February 1985; accepted in revised form 29 May 1985) Abstract-The mode of action of the enuresis alarm is not clear. Earlier work suggested that the wire mesh itself may alter sleep and in this way affect nocturnal enuresis. Seven healthy males have been studied within a two-period cross-over design in which their nocturnal motility, on and off an enuresis wire mesh, was recorded using a motility bed. There were no order, treatment or day effects in any of the variables studied. However, the mean hourly motility for each subject averaged over the three nights shows a substantial trend towards increased motility on the mesh. This lends some support to the hypothesis and merits further study.
IN 1974 CRISP and Hafner [ 1 ] reported a significant relationship between nocturnal enuresis and nocturnal motility. Enuresis was associated with low motility. In this context nocturnal motility is defined as movement whilst in bed during the night and it includes movements from turning over to minor changes in body position. The pad and buzzer is known to be an effective treatment for nocturnal enuresis. It is possible that the effect on motility of sleeping on a wire pad could account for a reduction in enuresis. However, in recent studies this hypothesis [ 1] was not borne out [2, 31. In these reports, in addition to recording nocturnal motility, the subjects were also wired up for polysomnography. The intrusiveness of this recording procedure might perhaps have affected sleep and nocturnal motility in ways that obscured any specific effect of the pad on motility. The purpose of the present experiment was to investigate the effect of sleeping on an enuresis alarm wire mesh pad whilst recording the night’s motility and using only the sleep motility recording apparatus.
METHOD The nocturnal motility recording device is connected to the bed frame and mattress base. The subject would be unaware of its presence unless specifically shown the apparatus and it should not, therefore, itself influence sleep. Movement of the subject causes a rod to move up and down between a light and a photocell [4]. A microprocessor counts the number of times the photocell is triggered in each 5 min period. These are summated to assess hourly motility and the results are printed out the following morning. The wire mesh was connected to the alarm in the usual way and remained live throughout the night. The modes of action of this equipment and of the motility bed were demonstrated to the subjects at the outset. Eight healthy non-enuretic male volunteers in the age range 18-25 yr took part. Seven were medical students and one was a male nurse. They reported no sleep difficulties and were not on any medication. The study had a two-period cross-over design. Half the subjects slept first on the wire mesh for five nights. After a break of one month control motility in the absence of the wire mesh was assessed for five nights. In the other subjects the order of the control and experimental situations was reversed. The individuals were randomly allocated to the two groups. The first night was regarded as an adaptation night. The subjects were instructed to refrain from alcohol and to retire to bed when they chose. The first hour’s data after retiring to bed were discarded. Measurements were made of total motility, total time in bed and motility hour by hour.
Department U.K.
of Psychiatry,
St George’s
Hospital
Medical School, Cranmer
63
Terrace,
London
SW17 ORE,
A. J. MACAULAY
64
et al.
The data were analysed using the BMD P2V program from the BMDP suite of programs [5]. This is the analysis of variance and co-variance, including repeated measures program. The method of analysis used was the usual one associated with a two-period cross-over design. (For a detailed description see [6] or [7] .) The method first tests to see if there is an order effect (i.e. do the subjects who sleep on the mesh first have different motility to those who have it in the second experimental period?). It then goes on to test whether there is a treatment effect (i.e. whether motility differs with or without the mesh) and then finally whether there is a ‘day’ effect; in other words, whether motility systematically changes from day to day under any particular experimental condition. We compared these exposures in terms of the three measures made, i.e. total motility, average motility and motility hour by hour.
RESULTS
One subject completed only the first week of the experiment and was dropped from the analysis. Due to equipment failure the second night was lost in each session for two subjects, so this night was dropped from the analysis for all subjects thus leaving a two-period study having three days in each of control and experimental situations. The analysis was performed as described in the methodology section above. There were found to be no statistically significant order, treatment or day effects, when using any of the three measures, i.e. total motility, average motility or motility hour by hour. However, Table I shows the mean hourly motility for each subject, averaged over the three nights, for both on-mesh and off-mesh experimental conditions. TABLE I.-AVERAGE
Subject
MOTILITY PER SUBJECT ON AND OFF MESH
On mesh Mean hourly motility
number
131.54 134.30 130.99 63.09 116.47 66.41 116.45 108.461
I
2 3 4 5 6 7 Average t= 1.91730;
HOURLY
p=O.O53
SD
2.16 3.17 16.77 7.90 22.63 12.17 20.58 30.721
Off mesh Mean hourly motility 109.64 143.53 69.34 32.90 95.70 73.50 110.51 90.73 1
SD
30.62 38.07 21.05 4.20 24.23 30.76 17.34 35.73
(one-tailed).
As can be seen there seems to be a trend towards greater motility in the on-mesh condition. A crude pairwise t-test to test for a difference between experimental conditions (i.e. using just the mean hourly motility over each of the three day periods and ignoring order and daily variation) gave a t-value of 1.92. This gave a one-tailed probability, given that this would be the expected direction for the difference, of 0.053, though obviously this result must be interpreted with caution.
DISCUSSION
Although there were no statistically significant trend shown by the mean hourly motility supports does alter nocturnal motility. It may thus lighten enuresis in subjects with this disability treated by the finding is in accord with that of a previous case
order, treatment or day effects, the the hypothesis that the wire mesh sleep and thereby reduce nocturnal the pad and buzzer. To this extent report [ 1] where pharmacologically
Nocturnal
motility
and the enuresis
alarm
device
65
induced nocturnal activation in an enuretic patient was associated with remission followed by subsequent relapse as the subject habituated to the drug and nocturnal activity diminished. A previous study similar to the present one failed to reveal any specific activating effect of the wire mesh but this may have been obscured by the blanket intrusiveness of EEG leads throughout the experiment. The present finding invites further investigation of the hypothesis, including investigation of the role of the wire mesh as a nocturnally activating agent in the treatment of nocturnal enuresis. Meanwhile, it is noteworthy that manufacturers are making the wire mesh more comfortable and, therefore less activating! Acknowledgement-This for which the authors
work has been supported are most grateful.
by a grant to AHC by the Wolfson
Charitable
Trust
REFERENCES activity and enuresis: a study of a 35year old male. J Neural 1. CRISP AH, HAFNER J. Nocturnal Neurosurgery Psychiat 1974; 31: 610-613. 2. SIRELING LI, CRISP AH. Sleep and the enuresis alarm device. J Sot Med 1983; 76: 131-133. activity and the enuresis alarm device. Postgrad Med 3. CRISP AH, SIRELING LI, FAIZEY J. Nocturnal J 1984; 60: 280-281. for the 4. CRISP AH, STONE~ILL E, EVERSDEN ID. The design of a motilitv bed including its calibration subject’s weight. Med Bio Eng 1970; 8: 455-463. Press. 1974. 5. DIXON WJ. BROWN MB. BMDP-7a. Berkelev: University of California cross:over clinical trial. Br J Clin Pha~rnacol 1979; 8: 7-20. 6. HILLS M, ARMITAGE P. The two-period 7. GRIZZLE JE. The two-period change-over design and its use in clinical trials. Biometrics 1968; 21: 467-480 and corrigenda 1974; 30: 727.
Journal of Printed in Great Britain.
Vol. 30. No.
THE RELATIONSHIP
I, pp. 63-65,
1986
0
BETWEEN NOCTURNAL
THE ENURESIS ALARM
0022-39996036 $3.00 + 0.W 1986 Pergamon Press Ltd.
MOTILITY
AND
DEVICE
A. J. MACAULAY, M. GUPTA, A. H. CRISP and A. V. BHAT (Received 22 February 1985; accepted in revised form 29 May 1985) Abstract-The mode of action of the enuresis alarm is not clear. Earlier work suggested that the wire mesh itself may alter sleep and in this way affect nocturnal enuresis. Seven healthy males have been studied within a two-period cross-over design in which their nocturnal motility, on and off an enuresis wire mesh, was recorded using a motility bed. There were no order, treatment or day effects in any of the variables studied. However, the mean hourly motility for each subject averaged over the three nights shows a substantial trend towards increased motility on the mesh. This lends some support to the hypothesis and merits further study.
IN 1974 CRISP and Hafner [ 1 ] reported a significant relationship between nocturnal enuresis and nocturnal motility. Enuresis was associated with low motility. In this context nocturnal motility is defined as movement whilst in bed during the night and it includes movements from turning over to minor changes in body position. The pad and buzzer is known to be an effective treatment for nocturnal enuresis. It is possible that the effect on motility of sleeping on a wire pad could account for a reduction in enuresis. However, in recent studies this hypothesis [ 1] was not borne out [2, 31. In these reports, in addition to recording nocturnal motility, the subjects were also wired up for polysomnography. The intrusiveness of this recording procedure might perhaps have affected sleep and nocturnal motility in ways that obscured any specific effect of the pad on motility. The purpose of the present experiment was to investigate the effect of sleeping on an enuresis alarm wire mesh pad whilst recording the night’s motility and using only the sleep motility recording apparatus.
METHOD The nocturnal motility recording device is connected to the bed frame and mattress base. The subject would be unaware of its presence unless specifically shown the apparatus and it should not, therefore, itself influence sleep. Movement of the subject causes a rod to move up and down between a light and a photocell [4]. A microprocessor counts the number of times the photocell is triggered in each 5 min period. These are summated to assess hourly motility and the results are printed out the following morning. The wire mesh was connected to the alarm in the usual way and remained live throughout the night. The modes of action of this equipment and of the motility bed were demonstrated to the subjects at the outset. Eight healthy non-enuretic male volunteers in the age range 18-25 yr took part. Seven were medical students and one was a male nurse. They reported no sleep difficulties and were not on any medication. The study had a two-period cross-over design. Half the subjects slept first on the wire mesh for five nights. After a break of one month control motility in the absence of the wire mesh was assessed for five nights. In the other subjects the order of the control and experimental situations was reversed. The individuals were randomly allocated to the two groups. The first night was regarded as an adaptation night. The subjects were instructed to refrain from alcohol and to retire to bed when they chose. The first hour’s data after retiring to bed were discarded. Measurements were made of total motility, total time in bed and motility hour by hour.
Department U.K.
of Psychiatry,
St George’s
Hospital
Medical School, Cranmer
63
Terrace,
London
SW17 ORE,
A. J. MACAULAY
64
et al.
The data were analysed using the BMD P2V program from the BMDP suite of programs [5]. This is the analysis of variance and co-variance, including repeated measures program. The method of analysis used was the usual one associated with a two-period cross-over design. (For a detailed description see [6] or [7] .) The method first tests to see if there is an order effect (i.e. do the subjects who sleep on the mesh first have different motility to those who have it in the second experimental period?). It then goes on to test whether there is a treatment effect (i.e. whether motility differs with or without the mesh) and then finally whether there is a ‘day’ effect; in other words, whether motility systematically changes from day to day under any particular experimental condition. We compared these exposures in terms of the three measures made, i.e. total motility, average motility and motility hour by hour.
RESULTS
One subject completed only the first week of the experiment and was dropped from the analysis. Due to equipment failure the second night was lost in each session for two subjects, so this night was dropped from the analysis for all subjects thus leaving a two-period study having three days in each of control and experimental situations. The analysis was performed as described in the methodology section above. There were found to be no statistically significant order, treatment or day effects, when using any of the three measures, i.e. total motility, average motility or motility hour by hour. However, Table I shows the mean hourly motility for each subject, averaged over the three nights, for both on-mesh and off-mesh experimental conditions. TABLE I.-AVERAGE
Subject
MOTILITY PER SUBJECT ON AND OFF MESH
On mesh Mean hourly motility
number
131.54 134.30 130.99 63.09 116.47 66.41 116.45 108.461
I
2 3 4 5 6 7 Average t= 1.91730;
HOURLY
p=O.O53
SD
2.16 3.17 16.77 7.90 22.63 12.17 20.58 30.721
Off mesh Mean hourly motility 109.64 143.53 69.34 32.90 95.70 73.50 110.51 90.73 1
SD
30.62 38.07 21.05 4.20 24.23 30.76 17.34 35.73
(one-tailed).
As can be seen there seems to be a trend towards greater motility in the on-mesh condition. A crude pairwise t-test to test for a difference between experimental conditions (i.e. using just the mean hourly motility over each of the three day periods and ignoring order and daily variation) gave a t-value of 1.92. This gave a one-tailed probability, given that this would be the expected direction for the difference, of 0.053, though obviously this result must be interpreted with caution.
DISCUSSION
Although there were no statistically significant trend shown by the mean hourly motility supports does alter nocturnal motility. It may thus lighten enuresis in subjects with this disability treated by the finding is in accord with that of a previous case
order, treatment or day effects, the the hypothesis that the wire mesh sleep and thereby reduce nocturnal the pad and buzzer. To this extent report [ 1] where pharmacologically
Nocturnal
motility
and the enuresis
alarm
device
65
induced nocturnal activation in an enuretic patient was associated with remission followed by subsequent relapse as the subject habituated to the drug and nocturnal activity diminished. A previous study similar to the present one failed to reveal any specific activating effect of the wire mesh but this may have been obscured by the blanket intrusiveness of EEG leads throughout the experiment. The present finding invites further investigation of the hypothesis, including investigation of the role of the wire mesh as a nocturnally activating agent in the treatment of nocturnal enuresis. Meanwhile, it is noteworthy that manufacturers are making the wire mesh more comfortable and, therefore less activating! Acknowledgement-This for which the authors
work has been supported are most grateful.
by a grant to AHC by the Wolfson
Charitable
Trust
REFERENCES activity and enuresis: a study of a 35year old male. J Neural 1. CRISP AH, HAFNER J. Nocturnal Neurosurgery Psychiat 1974; 31: 610-613. 2. SIRELING LI, CRISP AH. Sleep and the enuresis alarm device. J Sot Med 1983; 76: 131-133. activity and the enuresis alarm device. Postgrad Med 3. CRISP AH, SIRELING LI, FAIZEY J. Nocturnal J 1984; 60: 280-281. for the 4. CRISP AH, STONE~ILL E, EVERSDEN ID. The design of a motilitv bed including its calibration subject’s weight. Med Bio Eng 1970; 8: 455-463. Press. 1974. 5. DIXON WJ. BROWN MB. BMDP-7a. Berkelev: University of California cross:over clinical trial. Br J Clin Pha~rnacol 1979; 8: 7-20. 6. HILLS M, ARMITAGE P. The two-period 7. GRIZZLE JE. The two-period change-over design and its use in clinical trials. Biometrics 1968; 21: 467-480 and corrigenda 1974; 30: 727.