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Inspiratory pressure threshold training in a case of congenital bilateral abductor vocal fold paralysis
International Journal of Pediatric Otorhinolaryngology (2003) 67, 413 /416
www.elsevier.com/locate/ijporl
CASE REPORT
Inspiratory pressure threshold training in a case of congenital bilateral abductor vocal fold paralysis Susan E. Bakera,*, Christine M. Sapienzab, Savita Collinsc a
Department of Communication Sciences and Disorders, University of Florida, 63 Dauer Hall, P.O. Box 117420, Gainesville, FL 32611, USA b Department of Communication Sciences and Disorders, University of Florida, Gainesville, FL, USA c Department of Otolaryngology, University of Florida, Gainesville, FL, USA Received 11 July 2002; received in revised form 6 November 2002; accepted 6 November 2002
KEYWORDS Vocal fold paralysis; Respiratory muscle training; Exercise; Voice
Summary We present a non-surgical treatment option to decrease symptoms of dyspnea in a 6 year-old child with congenital bilateral abductor vocal fold paralysis. A respiratory muscle strength-training program was used to strengthen her inspiratory muscles for 8 months, 3 to 5 days per week. Inspiratory muscle strength increased over the course of training, resulting in reported decreases in dyspnea by both the child and parents during speech and exercise. – 2002 Elsevier Science Ireland Ltd. All rights reserved.
1. Introduction Vocal fold paralysis, a common cause of stridor and hoarseness in children, is estimated to be the second most frequent congenital abnormality of the upper airway [1,2]. Incidences of bilateral abductor paralysis of the vocal folds in a paramedian or midline position are less common than a unilateral paralysis [3] but when it does occur results in airway comprises requiring a tracheostomy in some patients. Surgical lateralization of the vocal folds is generally the recommended treatment for these patients to open the airway thus minimizing or negating the need for a tracheotomy. However, lateralization is not without complications as vocal quality and/or swallowing may be affected. This article presents a non-surgical treatment option implemented with a pediatric patient *Corresponding author. Tel.: /1-352-392-2046; fax: /1-352392-6170. E-mail address: [email protected] (S.E. Baker).
with congenital bilateral abductor vocal fold paralysis. This treatment emphasizes increasing inspiratory muscle strength training as a mechanism of compensating for a limited glottal airway and increased airway resistance.
2. Case 2.1. Patient history This 6 year-old female with congenital bilateral abductor vocal fold paralysis was seen at our clinic. The patient’s chief complaint was a feeling of breathlessness during exercise and difficulty speaking while walking even short distances. Her parents reported the presence of stridor during physical exertion, heard occasionally during breathing at rest. She was a full term baby and her parents reported that the childbirth was unremarkable. The parents reported, however, that the patient failed to thrive for approximately the first 9
0165-5876/03/$ - see front matter – 2002 Elsevier Science Ireland Ltd. All rights reserved. PII: S 0 1 6 5 - 5 8 7 6 ( 0 2 ) 0 0 3 8 9 - 0
414
S.E. Baker et al.
months of life, although she was never tracheotomized prior to enrollment in therapy. There was no history of dysphagia or any other major medical conditions with the exception of a lazy eye on the left side. Flexible laryngoscopy revealed limited vocal fold abduction bilaterally with greater amplitude of left vocal fold movement noted. There appeared to be a shelf of tissue or tethering between the arytenoids. A bronchoscopy was recommended, but has not yet been performed, to determine if there is an anatomic abnormality preventing full vocal fold abduction. The patient presented with a normal vocal quality characterized by occasional disruptions in fluency due to more frequent and longer inspirations. The patient demonstrated a normal range of loudness and pitch variability according to a clinically certified speech pathologist. Her average fundamental frequency prior to training was 275 Hz which is within normal limits for her age [4].
2.2. Intervention An inspiratory pressure-threshold training program was recommended for this patient to increase the strength of the inspiratory muscles. This recommendation was based on previous research in our laboratory at the University of Florida with two adult patients presenting with breathlessness during exercise and speech resulting from upper airway limitation. Both of these adult patients were able to strengthen inspiratory muscles with the threshold training program and reported a decreased sensation of breathlessness during exercise and speech [5,6]. The training is completed with an inspiratory pressure-threshold trainer that is cylindrical in shape and consists of a mouthpiece and a oneway valve controlled by a spring (Fig. 1). The one-
way valve is blocked until a sufficient amount of air pressure is sent through the cylinder to overcome the spring force of the valve. To achieve this pressure threshold, the patient must breathe in with sufficient inspiratory effort. As long as the threshold pressure is maintained, air flows through the device. The spring in the device is adjustable, allowing the required threshold pressure to be increased. At higher threshold pressures, greater inspiratory pressures are required of the patient. A weekly training program using the pressurethreshold device was prescribed for the patient. One training set consisted of the patient inspiring through the device five times in a row with brief 30 s to 1 min rests between each inspiration. Initially, the patient was instructed to complete three sets of these inspirations, five times during the week. Maximum inspiratory pressure (MIP) was the measure used to indicate inspiratory muscle strength. The measure was obtained with a pressure gauge at the beginning of training to guide the clinician to set the pressure-threshold on the trainer at the appropriate pressure threshold. Pressure-threshold settings were marked on the cylinder of the device in cmH2O. In order to obtain MIP, the patient was asked to expire to residual volume and then inspire as hard and fast as possible through a mouthpiece connected to a pressure gauge. In our previous studies of adult patients employing the use of this device, the pressure threshold setting was placed at 75% of MIP. This percentage is based on skeletal muscle training research that demonstrates that the most effective muscle strengthening occurs when a near maximal load is placed on the muscle [7]. However, this patient was not able to initially ‘break’ the threshold at 75% of her baseline MIP. Therefore, the clinician lowered the threshold to a level at which she could successfully complete the task. This level was set at 50% of her MIP or 21 cmH2O. The previously trained adult patients completed the training tasks at five sets, five times per week. A conservative approach was taken in regard to the expected endurance for this pediatric patient. This patient was instructed to initially complete three sets of the training tasks, five times per week. The number of sets was gradually increased to five.
3. Results
Fig. 1
Schematic of inspiratory muscle trainer.
The initial MIP for this patient was 41 cmH2O. Her MIP steadily increased during each week of the training (see Fig. 2). Her highest recorded MIP was 81 cmH2O during the third week of training. The trainer had been set at approximately 50% of the
Inspiratory pressure threshold training
415
Fig. 2 Average (MIP) before and after each training week. The above figure represents (MIP) taken at baseline and then following specified time points during the training. For example, the measure for Week 1 was taken after the first week of training.* It is suspected that there was equipment malfunction for this measurement.** The patient suffered from an upper respiratory infection for several weeks prior to this measurement.*** The patient completed the program at a reduced frequency to increase compliance.
average MIP each week. The measure of MIP is in question following the third week due to apparent equipment malfunction. Following the fifth week of training the patient suffered an upper respiratory infection and had to cease training for several weeks. During this break in the training program, the patient’s MIP decreased to 61 cmH2O, therefore the threshold setting and frequency of training were decreased to accommodate for the patient’s loss of strength. After approximately 4 months of training, the patient’s parents noted the length of the training program was beginning to become cumbersome for this child. In order to increase patient compliance with this program, the number of training sets was decreased to three. The patient maintained an average MIP of 63 cmH2O for several months, which was 50% higher than her initial MIP. A recent measurement of this patient’s MIP at 8 months of training revealed a substantial increase to 81 cmH2O. (Fig. 2). Currently, the patient reports less breathlessness during physical activity and ease of speaking during light exercise. Her parents report that she is occasionally able to speak during heavy exercise. They also stated that she appears to be able to tolerate an increased amount of exertion. The patient and her parents have provided anecdotal reports of changes in her activity level such as: a.) she recently broke her record in running distance during her physical education class at school, b.) she is able to swim farther during her swimming lessons than she was able to 1 year ago, c.) she is able to participate in physical activities at similar intensities and duration to her peers.
4. Discussion The sensation of dyspnea is debilitating from a functional standpoint making day-to-day living activities difficult to accomplish. Walking, lifting, speaking and exercising as well as other physical, mental and social tasks become difficult [8]. Combining these activities heightens the sensation of dyspnea, causing the patient to voluntarily diminish or stop engaging in them. The parents of this pediatric patient reported changes in the child’s tolerance of certain physical tasks and a decreased sensation of dyspnea when speaking and exercising in combination. Most notable that her dyspnea was reduced without the aid of further surgery or pharmacological intervention, but rather with a behavioral, shortterm, device driven therapy. Compliance with the therapy was very good; the patient attended all therapy sessions and only showed deterioration in the training effect when becoming ill with an upper respiratory infection. Reducing the number of days per week of training became necessary during a time when the child becomes less compliant. Issues of compliance arise during any behavioral therapy program and as such always need to be considered when attempting to modify behavior. The patient continues to train and maintain her initial training effect of /50% from baseline and most recently has improved her effect to 100% from baseline. Benefits of pressure threshold training include its substantial effect on reducing dyspnea in cases of upper airway limitation, its ability to be used in the home environment and its short training duration per day. Finally, it provides, particularly for the
416
S.E. Baker et al.
pediatric patient and parents, a tangible device driven program where outcome can be tracked and documented. The physiological outcome of threshold inspiratory muscle strength training is measurable and produces a positive functional outcome with regard to both exercise and speech production.
5. Conclusion Pressure threshold training is a treatment paradigm that has been developed through previous findings obtained from resistance-based techniques used in limb and respiratory muscle strength training. Conditions such as bilateral abductor vocal fold paralysis are challenging from a surgical standpoint because vocal quality may be sacrificed as a result of surgery to lateralize the vocal folds. This training program represents a possible rehabilitation modality to explore with other types of upper airway limitations prior to making major surgical decisions.
.
References [1] E. Friedman, A.L. deJong, M. Sulek, Pediatric bilateral vocal fold immobility: the role of carbon dioxide laser posterior transverse partial cordectomy, Ann. Otol. Rhinol. Laryngol. 110 (2001) 723 /728. [2] K.M. Grundfast, E. Harley, Vocal fold paralysis, Otolaryngol. Clin. North Am. 22 (1989) 569 /599. [3] R.I. Zbar, R.J. Smith, Vocal fold paralysis in infants twelve months of age and younger, Otolaryngol Head Neck Surg. 114 (1996) 18 /21. [4] Kent, R. Reference Manual for Communication Sciences and Disorders, PRO-ED Inc.,AustinTX, 1994. [5] C. Sapienza, J. Brown, D. Martin, P. Davenport, Inspiratory pressure threshold training for glottal airway limitation in laryngeal papilloma, J. Voice 13 (1999) 382 /388. [6] S. Baker, C. Sapienza, P. Davenport, D. Martin, B. Hoffman Ruddy, G. Woodson, Inspiratory muscle strength training in a patient with bilateral abductor vocal fold paralysis, J. Voice in press. [7] American College of Sports Medicine. Position stand on the recommended quantity and quality of exercise for developing and maintaining cardiorespiratory and muscular fitness, and flexibility in healthy adults, Med. Sci. Sports Exerc. (1998) 30. [8] E. Breslin, C. van der Schans, S. Bruekink, P. Meek, K. Mercer, W. Volz, S. Louie, Perception of fatigue and quality of life in patients with COPD, Chest 114 (1998) 958 /964.
www.elsevier.com/locate/ijporl
CASE REPORT
Inspiratory pressure threshold training in a case of congenital bilateral abductor vocal fold paralysis Susan E. Bakera,*, Christine M. Sapienzab, Savita Collinsc a
Department of Communication Sciences and Disorders, University of Florida, 63 Dauer Hall, P.O. Box 117420, Gainesville, FL 32611, USA b Department of Communication Sciences and Disorders, University of Florida, Gainesville, FL, USA c Department of Otolaryngology, University of Florida, Gainesville, FL, USA Received 11 July 2002; received in revised form 6 November 2002; accepted 6 November 2002
KEYWORDS Vocal fold paralysis; Respiratory muscle training; Exercise; Voice
Summary We present a non-surgical treatment option to decrease symptoms of dyspnea in a 6 year-old child with congenital bilateral abductor vocal fold paralysis. A respiratory muscle strength-training program was used to strengthen her inspiratory muscles for 8 months, 3 to 5 days per week. Inspiratory muscle strength increased over the course of training, resulting in reported decreases in dyspnea by both the child and parents during speech and exercise. – 2002 Elsevier Science Ireland Ltd. All rights reserved.
1. Introduction Vocal fold paralysis, a common cause of stridor and hoarseness in children, is estimated to be the second most frequent congenital abnormality of the upper airway [1,2]. Incidences of bilateral abductor paralysis of the vocal folds in a paramedian or midline position are less common than a unilateral paralysis [3] but when it does occur results in airway comprises requiring a tracheostomy in some patients. Surgical lateralization of the vocal folds is generally the recommended treatment for these patients to open the airway thus minimizing or negating the need for a tracheotomy. However, lateralization is not without complications as vocal quality and/or swallowing may be affected. This article presents a non-surgical treatment option implemented with a pediatric patient *Corresponding author. Tel.: /1-352-392-2046; fax: /1-352392-6170. E-mail address: [email protected] (S.E. Baker).
with congenital bilateral abductor vocal fold paralysis. This treatment emphasizes increasing inspiratory muscle strength training as a mechanism of compensating for a limited glottal airway and increased airway resistance.
2. Case 2.1. Patient history This 6 year-old female with congenital bilateral abductor vocal fold paralysis was seen at our clinic. The patient’s chief complaint was a feeling of breathlessness during exercise and difficulty speaking while walking even short distances. Her parents reported the presence of stridor during physical exertion, heard occasionally during breathing at rest. She was a full term baby and her parents reported that the childbirth was unremarkable. The parents reported, however, that the patient failed to thrive for approximately the first 9
0165-5876/03/$ - see front matter – 2002 Elsevier Science Ireland Ltd. All rights reserved. PII: S 0 1 6 5 - 5 8 7 6 ( 0 2 ) 0 0 3 8 9 - 0
414
S.E. Baker et al.
months of life, although she was never tracheotomized prior to enrollment in therapy. There was no history of dysphagia or any other major medical conditions with the exception of a lazy eye on the left side. Flexible laryngoscopy revealed limited vocal fold abduction bilaterally with greater amplitude of left vocal fold movement noted. There appeared to be a shelf of tissue or tethering between the arytenoids. A bronchoscopy was recommended, but has not yet been performed, to determine if there is an anatomic abnormality preventing full vocal fold abduction. The patient presented with a normal vocal quality characterized by occasional disruptions in fluency due to more frequent and longer inspirations. The patient demonstrated a normal range of loudness and pitch variability according to a clinically certified speech pathologist. Her average fundamental frequency prior to training was 275 Hz which is within normal limits for her age [4].
2.2. Intervention An inspiratory pressure-threshold training program was recommended for this patient to increase the strength of the inspiratory muscles. This recommendation was based on previous research in our laboratory at the University of Florida with two adult patients presenting with breathlessness during exercise and speech resulting from upper airway limitation. Both of these adult patients were able to strengthen inspiratory muscles with the threshold training program and reported a decreased sensation of breathlessness during exercise and speech [5,6]. The training is completed with an inspiratory pressure-threshold trainer that is cylindrical in shape and consists of a mouthpiece and a oneway valve controlled by a spring (Fig. 1). The one-
way valve is blocked until a sufficient amount of air pressure is sent through the cylinder to overcome the spring force of the valve. To achieve this pressure threshold, the patient must breathe in with sufficient inspiratory effort. As long as the threshold pressure is maintained, air flows through the device. The spring in the device is adjustable, allowing the required threshold pressure to be increased. At higher threshold pressures, greater inspiratory pressures are required of the patient. A weekly training program using the pressurethreshold device was prescribed for the patient. One training set consisted of the patient inspiring through the device five times in a row with brief 30 s to 1 min rests between each inspiration. Initially, the patient was instructed to complete three sets of these inspirations, five times during the week. Maximum inspiratory pressure (MIP) was the measure used to indicate inspiratory muscle strength. The measure was obtained with a pressure gauge at the beginning of training to guide the clinician to set the pressure-threshold on the trainer at the appropriate pressure threshold. Pressure-threshold settings were marked on the cylinder of the device in cmH2O. In order to obtain MIP, the patient was asked to expire to residual volume and then inspire as hard and fast as possible through a mouthpiece connected to a pressure gauge. In our previous studies of adult patients employing the use of this device, the pressure threshold setting was placed at 75% of MIP. This percentage is based on skeletal muscle training research that demonstrates that the most effective muscle strengthening occurs when a near maximal load is placed on the muscle [7]. However, this patient was not able to initially ‘break’ the threshold at 75% of her baseline MIP. Therefore, the clinician lowered the threshold to a level at which she could successfully complete the task. This level was set at 50% of her MIP or 21 cmH2O. The previously trained adult patients completed the training tasks at five sets, five times per week. A conservative approach was taken in regard to the expected endurance for this pediatric patient. This patient was instructed to initially complete three sets of the training tasks, five times per week. The number of sets was gradually increased to five.
3. Results
Fig. 1
Schematic of inspiratory muscle trainer.
The initial MIP for this patient was 41 cmH2O. Her MIP steadily increased during each week of the training (see Fig. 2). Her highest recorded MIP was 81 cmH2O during the third week of training. The trainer had been set at approximately 50% of the
Inspiratory pressure threshold training
415
Fig. 2 Average (MIP) before and after each training week. The above figure represents (MIP) taken at baseline and then following specified time points during the training. For example, the measure for Week 1 was taken after the first week of training.* It is suspected that there was equipment malfunction for this measurement.** The patient suffered from an upper respiratory infection for several weeks prior to this measurement.*** The patient completed the program at a reduced frequency to increase compliance.
average MIP each week. The measure of MIP is in question following the third week due to apparent equipment malfunction. Following the fifth week of training the patient suffered an upper respiratory infection and had to cease training for several weeks. During this break in the training program, the patient’s MIP decreased to 61 cmH2O, therefore the threshold setting and frequency of training were decreased to accommodate for the patient’s loss of strength. After approximately 4 months of training, the patient’s parents noted the length of the training program was beginning to become cumbersome for this child. In order to increase patient compliance with this program, the number of training sets was decreased to three. The patient maintained an average MIP of 63 cmH2O for several months, which was 50% higher than her initial MIP. A recent measurement of this patient’s MIP at 8 months of training revealed a substantial increase to 81 cmH2O. (Fig. 2). Currently, the patient reports less breathlessness during physical activity and ease of speaking during light exercise. Her parents report that she is occasionally able to speak during heavy exercise. They also stated that she appears to be able to tolerate an increased amount of exertion. The patient and her parents have provided anecdotal reports of changes in her activity level such as: a.) she recently broke her record in running distance during her physical education class at school, b.) she is able to swim farther during her swimming lessons than she was able to 1 year ago, c.) she is able to participate in physical activities at similar intensities and duration to her peers.
4. Discussion The sensation of dyspnea is debilitating from a functional standpoint making day-to-day living activities difficult to accomplish. Walking, lifting, speaking and exercising as well as other physical, mental and social tasks become difficult [8]. Combining these activities heightens the sensation of dyspnea, causing the patient to voluntarily diminish or stop engaging in them. The parents of this pediatric patient reported changes in the child’s tolerance of certain physical tasks and a decreased sensation of dyspnea when speaking and exercising in combination. Most notable that her dyspnea was reduced without the aid of further surgery or pharmacological intervention, but rather with a behavioral, shortterm, device driven therapy. Compliance with the therapy was very good; the patient attended all therapy sessions and only showed deterioration in the training effect when becoming ill with an upper respiratory infection. Reducing the number of days per week of training became necessary during a time when the child becomes less compliant. Issues of compliance arise during any behavioral therapy program and as such always need to be considered when attempting to modify behavior. The patient continues to train and maintain her initial training effect of /50% from baseline and most recently has improved her effect to 100% from baseline. Benefits of pressure threshold training include its substantial effect on reducing dyspnea in cases of upper airway limitation, its ability to be used in the home environment and its short training duration per day. Finally, it provides, particularly for the
416
S.E. Baker et al.
pediatric patient and parents, a tangible device driven program where outcome can be tracked and documented. The physiological outcome of threshold inspiratory muscle strength training is measurable and produces a positive functional outcome with regard to both exercise and speech production.
5. Conclusion Pressure threshold training is a treatment paradigm that has been developed through previous findings obtained from resistance-based techniques used in limb and respiratory muscle strength training. Conditions such as bilateral abductor vocal fold paralysis are challenging from a surgical standpoint because vocal quality may be sacrificed as a result of surgery to lateralize the vocal folds. This training program represents a possible rehabilitation modality to explore with other types of upper airway limitations prior to making major surgical decisions.
.
References [1] E. Friedman, A.L. deJong, M. Sulek, Pediatric bilateral vocal fold immobility: the role of carbon dioxide laser posterior transverse partial cordectomy, Ann. Otol. Rhinol. Laryngol. 110 (2001) 723 /728. [2] K.M. Grundfast, E. Harley, Vocal fold paralysis, Otolaryngol. Clin. North Am. 22 (1989) 569 /599. [3] R.I. Zbar, R.J. Smith, Vocal fold paralysis in infants twelve months of age and younger, Otolaryngol Head Neck Surg. 114 (1996) 18 /21. [4] Kent, R. Reference Manual for Communication Sciences and Disorders, PRO-ED Inc.,AustinTX, 1994. [5] C. Sapienza, J. Brown, D. Martin, P. Davenport, Inspiratory pressure threshold training for glottal airway limitation in laryngeal papilloma, J. Voice 13 (1999) 382 /388. [6] S. Baker, C. Sapienza, P. Davenport, D. Martin, B. Hoffman Ruddy, G. Woodson, Inspiratory muscle strength training in a patient with bilateral abductor vocal fold paralysis, J. Voice in press. [7] American College of Sports Medicine. Position stand on the recommended quantity and quality of exercise for developing and maintaining cardiorespiratory and muscular fitness, and flexibility in healthy adults, Med. Sci. Sports Exerc. (1998) 30. [8] E. Breslin, C. van der Schans, S. Bruekink, P. Meek, K. Mercer, W. Volz, S. Louie, Perception of fatigue and quality of life in patients with COPD, Chest 114 (1998) 958 /964.