\
VENTILATION AND SWALLOWING INTERACTIONS OF NORMAL CHILDREN AND CHILDREN WITH CEREBRAL PALSY Karen A . McPherson David J . Kenny Ruth Koheil Kazik Bablich Alex Sochaniwskyj Morris Milner
. Cerebral palsy (CP) is a general term,for a gr up of disabling symptoms that result damage to the developing brain. Ma y central and peripheral structures and functions are affected. The most obvious sign of CP is dysfunction of motor control, so it is customary to describe the child with CP according to the type of motor disturbance, such as spastic or athetoid, even though individuals rarely, if ever, have 'pure' forms, and inter-rater reliability for the classification of such children is only moderate (Blair and Stanley 1985). Ventilation is another function affected by CP. Bjure and Berg (1970) found that children with athetosis have a 50 per cent decrease in vital capacity, while those with spastic CP. have a 67 per cent decrease. Hardy (1964) also noted a reduction in vital capacity of 49 per cent in children with athetoid CP and of 65 per cent in children with spastic CP. Decreased sensory input in children with CP can lead to chronically aspirated saliva or food. This is not usually accompanied by visible signs such as coughing or gagging (Logemann 1983), and can lead to pathosis. Children with CP have a high incidence of pneumonia and upper r&pirdtory-tract problems (Helfrich-Miller et al. 1984). CP affects the oral phase of swallowing: disorders commonly described include
fr?
tongue-thrust, prolonged and exaggerated bite reflex, hyper- or hypoactive gag reflex, tactile hypersensitivity in the oral area and drooling (Mueller 1974, Helfrich-Miller et al. 1984, Patrick and Gisel 1992). Inadequate function of the oral muscles interferes with the ability to maintain lip-seal and to transport ingested material to the pharyngeal area of the oral cavity, where the involuntary swallow reflex is initiated (Sochaniswkyj et al. 1986, Griggs et &I. 1989). Poor headcontrol and impaired palatal function also affect the ability to swallow. Ventilation and swallowing are closely related functions. As the pharynx serves both a ventilatory and alimentary role, a complex system of neural reflexes must operate to separate these two functions. Since CP affects both these functions, it is likely that ventilatory-alimentary coordination is also affected. Unfortunately, very4ew studies have dealt with the effects of swallowing on respiratory patterns in either healthy or diseased states, partly because of the difficulties in measuring both patterns simultaneously. Both the spirometer and pneumotachograph require the patient to breathe into a mouthpiece or face-mask, which prevents the patient taking food or liquid into the mouth. However, the development of the respiratory inductance plethysmograph (RIP) has eliminated this problem.
p
is
B
5 77
TABLE I Children's ages Group
Normal Spastic CP Athetoid CP .~
M
.-C
-$ E
v)
U
m
-.-C
.-
m
C
>"
5 78
N
I1 I1 11
Age (yrs:mihs)
Range
Mean
4:lO-12:4 5:3-10:9 4:10-10:7
8:s 7:l 6:7
The RIP was used in this study- for analysis of the ventilatory cycle during drinking, chewing and swallowing in one group of normal children and t q o groups with CP. Numerous therapies involve techniques such as stabilization of the jaw, cooling of the fauces and application of pressure to the tongue. None of these techniques has been tested for validity; until the outcomes of these therapeutic options have been verified, much treatment is based on conjecture. Our study provides quantitative data to serve as a foundation for further investigations of ventilation and swallowing interactions.
Subjects and method Three groups of children aged between five and 12 years participated in the study, The first group consisted of 11 children without neurological impairments, the second comprised 11 children with spastic CP and the third comprised 11 children with athetosis (Tab17 I). These groups were classified according to medical diagnoses, with awareness of the limitations of such classifications (Blair and Stanley 1985). The children with CP had a wide range of feeding abilities that clearly differed from able-bodied individuals, but none had needed surgical intervention (e.g. gastrostomy). All of the children with CP lacked normal head-control. Children with upper or lower respiratory-tract infection or chrmic obstructive pulmonary disease were excluded from all groups. The RIP (Respitrace') was used to monitor respiratory movements of the chest wall and abdomen. Respiratory movements elicit changes in the crosssectional area of the rib cage and
abdominal compartments, and alter the inductances of the coils in the R I P bands. This change in inductance was measured by placing each coil in an oscillator circuit,.so that changes in the volume of the enclosed part due to ventilation and the subsequent inductance changes in the RIP bands were indicated by changes in the frequencies of the oscillators. Three channels of respiratory information-rib cage (RC), abdomen (ABD) and tidal recorded volume (RC + ABD = TV)-were on an 8-channel chart recorder', A pneum~tachograph~ was used to calibrate the RIP. A desktop computer4 was used to analyse signals from the RIP and pneumotachograph and calculate volumemotion (V-M) coefficients in the calibration procedure. The first 44 sessions were calibrated using the simultaneous equation method; the remaining 55 sessions used the multiple linear regression technique. This change in calibration did not affect this part of the study, since the data reported here are temporal and relative values of ventilatory measures. Surface electromyography (EMG) from the left infrahyoid group of muscles was used to identify. swallows. In addition, EMG activity of the left masseter muscle was monitored. Bipolar silver-silver chloride Beckman miniature surface electrodes' were used. EMG signals were monitored and pre-processed by an Autogen 1700 myograph6. The 100 to 200Hz bandpass was selected; the signals were full-wave rectified and integrated over 50ms. Each child participated in three sessions, each of which followed this Drotocol: Quiet breathing until the childCwas comfortable and at ease Three minutes of monitored quiet breathing Child asked to take as big a breath as possible, hold it for as long as they felt comfortable and then relax Repeat big breath 'Ambulatory Monitoring Inc., Ardsley, NY 1052. 'Could No. 481: Gould Inc., Cleveland, OH 441 14. 'Fleisch Pneurnotachograph No. 73 19: Bionetics {Distfibutor), Toronto, Ontario. Zenith 158 (IBM PC-XT Compatible). 'Beckman 650414: Beckman Instruments Inc., Schiller Park, IL 60176. 6Autogen 1700 Feedback Myograph: Autogenic Systems Inc., Berkley, CA 94710.
TABLE I1 Big-breath task L
-
C
-
.
-
-
-
-
*
Could not do (%)*
Meah
0 12-3 58.5 35.4
14-2 7.3 2.8 5.8
Group
p
Normal Spastic CP ~
Athetoid CP >'Ail CP
-
BTl (s)
BT2 (s)f
(SO) Mean
(SO)
(6.1) (7-2) (2-4) (6.4)
(5.8) (6.3) (7-5) (6.7)
11.9 9.8 11.4 10.3
BI
d
(%)?
m
40.0 29.8 25-9 28.6
'
*p
VENTILATION AND SWALLOWING INTERACTIONS OF NORMAL CHILDREN AND CHILDREN WITH CEREBRAL PALSY Karen A . McPherson David J . Kenny Ruth Koheil Kazik Bablich Alex Sochaniwskyj Morris Milner
. Cerebral palsy (CP) is a general term,for a gr up of disabling symptoms that result damage to the developing brain. Ma y central and peripheral structures and functions are affected. The most obvious sign of CP is dysfunction of motor control, so it is customary to describe the child with CP according to the type of motor disturbance, such as spastic or athetoid, even though individuals rarely, if ever, have 'pure' forms, and inter-rater reliability for the classification of such children is only moderate (Blair and Stanley 1985). Ventilation is another function affected by CP. Bjure and Berg (1970) found that children with athetosis have a 50 per cent decrease in vital capacity, while those with spastic CP. have a 67 per cent decrease. Hardy (1964) also noted a reduction in vital capacity of 49 per cent in children with athetoid CP and of 65 per cent in children with spastic CP. Decreased sensory input in children with CP can lead to chronically aspirated saliva or food. This is not usually accompanied by visible signs such as coughing or gagging (Logemann 1983), and can lead to pathosis. Children with CP have a high incidence of pneumonia and upper r&pirdtory-tract problems (Helfrich-Miller et al. 1984). CP affects the oral phase of swallowing: disorders commonly described include
fr?
tongue-thrust, prolonged and exaggerated bite reflex, hyper- or hypoactive gag reflex, tactile hypersensitivity in the oral area and drooling (Mueller 1974, Helfrich-Miller et al. 1984, Patrick and Gisel 1992). Inadequate function of the oral muscles interferes with the ability to maintain lip-seal and to transport ingested material to the pharyngeal area of the oral cavity, where the involuntary swallow reflex is initiated (Sochaniswkyj et al. 1986, Griggs et &I. 1989). Poor headcontrol and impaired palatal function also affect the ability to swallow. Ventilation and swallowing are closely related functions. As the pharynx serves both a ventilatory and alimentary role, a complex system of neural reflexes must operate to separate these two functions. Since CP affects both these functions, it is likely that ventilatory-alimentary coordination is also affected. Unfortunately, very4ew studies have dealt with the effects of swallowing on respiratory patterns in either healthy or diseased states, partly because of the difficulties in measuring both patterns simultaneously. Both the spirometer and pneumotachograph require the patient to breathe into a mouthpiece or face-mask, which prevents the patient taking food or liquid into the mouth. However, the development of the respiratory inductance plethysmograph (RIP) has eliminated this problem.
p
is
B
5 77
TABLE I Children's ages Group
Normal Spastic CP Athetoid CP .~
M
.-C
-$ E
v)
U
m
-.-C
.-
m
C
>"
5 78
N
I1 I1 11
Age (yrs:mihs)
Range
Mean
4:lO-12:4 5:3-10:9 4:10-10:7
8:s 7:l 6:7
The RIP was used in this study- for analysis of the ventilatory cycle during drinking, chewing and swallowing in one group of normal children and t q o groups with CP. Numerous therapies involve techniques such as stabilization of the jaw, cooling of the fauces and application of pressure to the tongue. None of these techniques has been tested for validity; until the outcomes of these therapeutic options have been verified, much treatment is based on conjecture. Our study provides quantitative data to serve as a foundation for further investigations of ventilation and swallowing interactions.
Subjects and method Three groups of children aged between five and 12 years participated in the study, The first group consisted of 11 children without neurological impairments, the second comprised 11 children with spastic CP and the third comprised 11 children with athetosis (Tab17 I). These groups were classified according to medical diagnoses, with awareness of the limitations of such classifications (Blair and Stanley 1985). The children with CP had a wide range of feeding abilities that clearly differed from able-bodied individuals, but none had needed surgical intervention (e.g. gastrostomy). All of the children with CP lacked normal head-control. Children with upper or lower respiratory-tract infection or chrmic obstructive pulmonary disease were excluded from all groups. The RIP (Respitrace') was used to monitor respiratory movements of the chest wall and abdomen. Respiratory movements elicit changes in the crosssectional area of the rib cage and
abdominal compartments, and alter the inductances of the coils in the R I P bands. This change in inductance was measured by placing each coil in an oscillator circuit,.so that changes in the volume of the enclosed part due to ventilation and the subsequent inductance changes in the RIP bands were indicated by changes in the frequencies of the oscillators. Three channels of respiratory information-rib cage (RC), abdomen (ABD) and tidal recorded volume (RC + ABD = TV)-were on an 8-channel chart recorder', A pneum~tachograph~ was used to calibrate the RIP. A desktop computer4 was used to analyse signals from the RIP and pneumotachograph and calculate volumemotion (V-M) coefficients in the calibration procedure. The first 44 sessions were calibrated using the simultaneous equation method; the remaining 55 sessions used the multiple linear regression technique. This change in calibration did not affect this part of the study, since the data reported here are temporal and relative values of ventilatory measures. Surface electromyography (EMG) from the left infrahyoid group of muscles was used to identify. swallows. In addition, EMG activity of the left masseter muscle was monitored. Bipolar silver-silver chloride Beckman miniature surface electrodes' were used. EMG signals were monitored and pre-processed by an Autogen 1700 myograph6. The 100 to 200Hz bandpass was selected; the signals were full-wave rectified and integrated over 50ms. Each child participated in three sessions, each of which followed this Drotocol: Quiet breathing until the childCwas comfortable and at ease Three minutes of monitored quiet breathing Child asked to take as big a breath as possible, hold it for as long as they felt comfortable and then relax Repeat big breath 'Ambulatory Monitoring Inc., Ardsley, NY 1052. 'Could No. 481: Gould Inc., Cleveland, OH 441 14. 'Fleisch Pneurnotachograph No. 73 19: Bionetics {Distfibutor), Toronto, Ontario. Zenith 158 (IBM PC-XT Compatible). 'Beckman 650414: Beckman Instruments Inc., Schiller Park, IL 60176. 6Autogen 1700 Feedback Myograph: Autogenic Systems Inc., Berkley, CA 94710.
TABLE I1 Big-breath task L
-
C
-
.
-
-
-
-
*
Could not do (%)*
Meah
0 12-3 58.5 35.4
14-2 7.3 2.8 5.8
Group
p
Normal Spastic CP ~
Athetoid CP >'Ail CP
-
BTl (s)
BT2 (s)f
(SO) Mean
(SO)
(6.1) (7-2) (2-4) (6.4)
(5.8) (6.3) (7-5) (6.7)
11.9 9.8 11.4 10.3
BI
d
(%)?
m
40.0 29.8 25-9 28.6
'
*p
