Auditory Processing Disorder (CAPD)
Auditory Processing Literature Review
In the past, there has been difficulty in defining what is known as (central) auditory processing disorder (CAPD), its definition is constantly changing with the most recent being produced by the American Speech-Language-Hearing Association (ASHA, 2005) stating that “(C)APD is a deficit in neural processing of auditory stimuli that is not due to higher order language, cognitive, or related factors” (ASHA, 2005; Wilson et al., 2012) however, this definition is not accepted by everyone (Kamhi, 2011). Attempts to clearly define CAPD and differentiate it from other disorders continue. There is an abundance of research that comments on the difficulty in the differential diagnosis of CAPD and the comorbidity …show more content…
of CAPD with other disorders (Cook et al., 1993; Gascon et al., 1986; Gomez et al., 1999; Keller et al., 2002; Riccio et al., 1994). The disorders most commonly associated with CAPD are Attention Deficit Hyperactivity Disorder (ADHD) and Attention Deficit Disorder (ADD) with many studies documenting the relationship between the two (Cook et al., 1993; Gascon et al., 1986; Gomez et al., 1999; Kamhi, 2011; Keller et al., 2002; Riccio et al., 1994). Furthermore it is important to obtain a better understanding of the processes used to differentially diagnose this disorder as well as the similarities between other disorders. The literature indicates that CAPD often occurs with other disorders, suggesting that a multidisciplinary approach may be most beneficial for correct diagnosis (Emanuel et al., 2011).
“The integrity of CAPD as a discreet diagnostic entity has been questioned by some researchers” (Cook et al., 1993). “Ludlow et al. (1983) described a weak link between CAPD and language disabilities in children” (Cook et al., 1993), Kamhi (2011) stated “we have expended too much time, energy, and resources trying to understand and treat a disorder that has not only defied definition, but lacks clear diagnostic criteria” and Wilson et al. (2012) “suggest that calls to abandon the use of (C)APD as a global label be supported”. While others (Gascon et all., 1986; Cook et al., 1993) have suggested that the diagnostic criteria for CAPD and ADD contain many features which make the disorders clinically similar. Many common characteristics of CAPD – poor attention and concentration, distractibility and fidgeting – are also clinical symptoms for a diagnosis of ADD and ADHD (Cook et al., 1993; Gomez et al., 1999). This similarity shows how easy a misdiagnosis can be due to the overlap in the behavioural symptoms of these disorders (Cook et al., 1993; Riccio et al., 1996).
Emanuel et al. (2011) conducted a survey to determine the current protocols used by audiologists in diagnosing children with CAPD. A previous study conducted by Emanuel (2002) stated that there isn’t enough normative data on auditory processing disorder (APD) tests which complicates differential diagnosis. To date there is no consensus regarding the tests that should make up a basic auditory processing battery, “the most recent guidelines, published by ASHA (2005) and the American Academy of Audiology (AAA, 2010), indicate that APD assessment should not be driven by a minimum test battery, but instead the test battery should be based on the individual’s case history and other information provided to the audiologist” (Emanuel et al., 2011).
This lack of consensus and clear diagnostic criteria (Emanuel et al., 2011; Kamhi, 2011) aids in the difficulty with differential diagnosis of the two disorders. Emanuel et al (2011) found that clinical audiologists were completing a relatively consistent approach towards the diagnosis of APD and included input from other multidisciplinary specialists. It was also found that those participating in the study believed that diagnosing APD and recommendations for treatment and management was the responsibility of the audiologist however they believed that speech-language pathologists had the obligation of enforcing treatment (Emanuel et al., 2011).
Many studies mention the relationship between CAPD with ADD/ADHD; Gascon et al. (1986) assessed a small number of children who met the criteria for ADD on neurodevelopmental stimuli and central auditory processing (CAP) tests. A high agreement was found between the questionnaires and the CAP tests, participants then received stimulant treatment and were re-assessed, the results after treatment again showed a high concordance and it was concluded that the CAP test battery used was more sensitive to the effects of stimulant medication than neurodevelopmental assessments (Gascon et al., 1986). Cook et al. (1993) conducted a study to further assess the effect of stimulant treatment and comorbidity of CAPD and ADHD. The participants also showed a positive response to treatment as seen in the follow up assessment results. It was concluded that CAPD and ADHD are closely related and the use of stimulants to treat both CAPD and ADHD is beneficial (Cook et al., 1993). Conversely, Tillery et al. (2000) conducted a study to examine the effects of methylphenidate on auditory processing tests in children diagnosed with both CAPD and ADHD. Participants were divided into two groups of 16, one group received the dose of methylphenidate first and the other received the placebo first. Participants were tested after each period of receiving either methylphenidate or the placebo. The results of the Tillery et al. (2000) study found that “although methylphenidate reduced impulsivity and enhanced attention, it did not eliminate auditory dysfunction.” It was also found from the results of this study “one might infer that CAPD and ADHD are independent, but often occur together” (Tillery et al., 2000). The differences in results of this study (Tillery et al., 2000) to the other two studies (Cook et al., 1993; Gascon et al., 1986) could be due to “the participants’ diagnosis of ADHD being made just before the beginning of their assessments” meaning that stimulant medication used may not have been titrated properly, this differs from the Tillery et al. (2000) study as participants had an existing diagnosis of ADHD, meaning that “medication dosages had already been titrated” (Tillery et al., 2000).
Review of the literature available relating to central auditory processing disorder (CAPD) shows that while there have been many studies conducted which have been able to provide insight into CAPD it is clear that further investigation needs to be undertaken.
The formulation of test batteries and standardized measures along with normative data is an important step to take in the advancement of understanding central auditory processing disorder. Many of the studies reviewed used similar methods along with small sample sizes preventing the results from being generalized to a greater population. From this it is clear that when conducting studies regarding CAPD, different methods need to be taken in order to produce “more conclusive findings” (Riccio et al., 1996) not only about CAPD including its diagnosis, but also about the relationship between CAPD and ADHD and how they differ. Due to limitations seen from the studies reviewed, a number of studies have questioned whether CAPD is “truly a distinct clinical entity” (Kamhi, 2011). Gomez et al. (1999) suggested that CAPD’s are more likely to be associated with learning disabilities than ADHD, proving that “CAPD and ADHD can occur as two distinct disorders” (Riccio et al., 1996). The use of stimulant medication to treat CAPD symptoms has achieved various results suggesting that further studies need to be undertaken to determine whether stimulant treatment is a reliable and beneficial treatment for CAPD. Keller et al. (2002) …show more content…
suggested that the use of subtypes for APD may be an important role in the differential diagnosis of APD as well as ADHD and other learning disabilities to prevent the occurrence of a misdiagnosis. Furthermore it is important to use a multidisciplinary approach to effectively and correctly diagnose CAPD, input from speech pathologists, audiologists, psychologists, teachers and parents should be taken into account to ensure a correct diagnosis. Not only does input from all these professionals help with obtaining a correct diagnosis it also assists with providing the correct treatment, whether that be from medication or other therapies. Without correct assessment procedures, differential diagnosis is not possible and the necessary intervention along with treatment and therapies cannot be determined (Riccio et al., 1996).
RESOURCES
American Speech-Language-Hearing Association. (2005). (Central) auditory processing disorders. Available from http://www.asha.org/policy/TR2005-00043.htm#sec1.3 -**
Cook, J. R., Mausback, T., Burd, L., Gascon, G. G., Slotnick, H. B., Patterson, B., Johnson, R. D., Hankey, B., & Reynolds, B. W. (1993). A preliminary study of the relationship between central auditory processing disorder and attention deficit disorder. Journal of Psychiatry & Neuroscience, 18(3), 130-137.
Emanual, D. (2002). The Auditory Processing Battery: Survey of Common Practices. Journal of the American Academy Audiology, 13:93-117.
Emanuel, D. C., Ficca, K. N., & Korczak, P. (2011). Survey of the diagnosis and management of auditory processing disorder. American Journal of Audiology, 20(1), 48-60.
Gascon, G.
G., Johnson, R. and Burd, L. (1986) Central Auditory Processing and Attention Deficit Disorders. Journal of Child Neurology, 1:27-33.
Gomez, R., & Condon, M. (1999). Central Auditory Processing Ability in Children with ADHD With and Without Learning Disabilities. Journal of Learning Disabilities, 32(2), 150-158.
Kamhi, A. G. (2011). What Speech-Language Pathologists Need to Know About Auditory Processing Disorder. Language, Speech and Hearing Services in Schools, 42:265-272.
Keller, W. D., & Tillery, K. L. (2002). Reliable Differential Diagnosis and Effective Management of Auditory Processing and Attention Deficit Hyperactivity Disorders. Seminars in Hearing, 23(4), 337-347.
Ludlow, C.L., Cudahey, E.A., Bassich, C., & Brown, G.L. (1983). Auditory processing skills of hyperactive, language impaired, and reading disabled boys. Central Auditory Processing Disorders. Baltimore, MD: University Park Press, 163-184.
Riccio, C. A., & Hynd, G. W. (1996). Relationship Between ADHD and Central Auditory Processing Disorder. School Psychology International, 17:235-252.
Tillery, K., Katz, J., Keller, W., (2000). Effects of methylphenidate (Ritalin™) on auditory performance in children with attention and auditory processing disorders. Journal of Speech, Language, and Hearing Research,
43:893–901.
Wilson, W. J., & Arnott, W. (2012). Using different criteria to diagnose (C)APD: how big a difference does it make? Journal of Speech, Language, and Hearing Research, doi:10.1044/1092-4388
In the past, there has been difficulty in defining what is known as (central) auditory processing disorder (CAPD), its definition is constantly changing with the most recent being produced by the American Speech-Language-Hearing Association (ASHA, 2005) stating that “(C)APD is a deficit in neural processing of auditory stimuli that is not due to higher order language, cognitive, or related factors” (ASHA, 2005; Wilson et al., 2012) however, this definition is not accepted by everyone (Kamhi, 2011). Attempts to clearly define CAPD and differentiate it from other disorders continue. There is an abundance of research that comments on the difficulty in the differential diagnosis of CAPD and the comorbidity …show more content…
of CAPD with other disorders (Cook et al., 1993; Gascon et al., 1986; Gomez et al., 1999; Keller et al., 2002; Riccio et al., 1994). The disorders most commonly associated with CAPD are Attention Deficit Hyperactivity Disorder (ADHD) and Attention Deficit Disorder (ADD) with many studies documenting the relationship between the two (Cook et al., 1993; Gascon et al., 1986; Gomez et al., 1999; Kamhi, 2011; Keller et al., 2002; Riccio et al., 1994). Furthermore it is important to obtain a better understanding of the processes used to differentially diagnose this disorder as well as the similarities between other disorders. The literature indicates that CAPD often occurs with other disorders, suggesting that a multidisciplinary approach may be most beneficial for correct diagnosis (Emanuel et al., 2011).
“The integrity of CAPD as a discreet diagnostic entity has been questioned by some researchers” (Cook et al., 1993). “Ludlow et al. (1983) described a weak link between CAPD and language disabilities in children” (Cook et al., 1993), Kamhi (2011) stated “we have expended too much time, energy, and resources trying to understand and treat a disorder that has not only defied definition, but lacks clear diagnostic criteria” and Wilson et al. (2012) “suggest that calls to abandon the use of (C)APD as a global label be supported”. While others (Gascon et all., 1986; Cook et al., 1993) have suggested that the diagnostic criteria for CAPD and ADD contain many features which make the disorders clinically similar. Many common characteristics of CAPD – poor attention and concentration, distractibility and fidgeting – are also clinical symptoms for a diagnosis of ADD and ADHD (Cook et al., 1993; Gomez et al., 1999). This similarity shows how easy a misdiagnosis can be due to the overlap in the behavioural symptoms of these disorders (Cook et al., 1993; Riccio et al., 1996).
Emanuel et al. (2011) conducted a survey to determine the current protocols used by audiologists in diagnosing children with CAPD. A previous study conducted by Emanuel (2002) stated that there isn’t enough normative data on auditory processing disorder (APD) tests which complicates differential diagnosis. To date there is no consensus regarding the tests that should make up a basic auditory processing battery, “the most recent guidelines, published by ASHA (2005) and the American Academy of Audiology (AAA, 2010), indicate that APD assessment should not be driven by a minimum test battery, but instead the test battery should be based on the individual’s case history and other information provided to the audiologist” (Emanuel et al., 2011).
This lack of consensus and clear diagnostic criteria (Emanuel et al., 2011; Kamhi, 2011) aids in the difficulty with differential diagnosis of the two disorders. Emanuel et al (2011) found that clinical audiologists were completing a relatively consistent approach towards the diagnosis of APD and included input from other multidisciplinary specialists. It was also found that those participating in the study believed that diagnosing APD and recommendations for treatment and management was the responsibility of the audiologist however they believed that speech-language pathologists had the obligation of enforcing treatment (Emanuel et al., 2011).
Many studies mention the relationship between CAPD with ADD/ADHD; Gascon et al. (1986) assessed a small number of children who met the criteria for ADD on neurodevelopmental stimuli and central auditory processing (CAP) tests. A high agreement was found between the questionnaires and the CAP tests, participants then received stimulant treatment and were re-assessed, the results after treatment again showed a high concordance and it was concluded that the CAP test battery used was more sensitive to the effects of stimulant medication than neurodevelopmental assessments (Gascon et al., 1986). Cook et al. (1993) conducted a study to further assess the effect of stimulant treatment and comorbidity of CAPD and ADHD. The participants also showed a positive response to treatment as seen in the follow up assessment results. It was concluded that CAPD and ADHD are closely related and the use of stimulants to treat both CAPD and ADHD is beneficial (Cook et al., 1993). Conversely, Tillery et al. (2000) conducted a study to examine the effects of methylphenidate on auditory processing tests in children diagnosed with both CAPD and ADHD. Participants were divided into two groups of 16, one group received the dose of methylphenidate first and the other received the placebo first. Participants were tested after each period of receiving either methylphenidate or the placebo. The results of the Tillery et al. (2000) study found that “although methylphenidate reduced impulsivity and enhanced attention, it did not eliminate auditory dysfunction.” It was also found from the results of this study “one might infer that CAPD and ADHD are independent, but often occur together” (Tillery et al., 2000). The differences in results of this study (Tillery et al., 2000) to the other two studies (Cook et al., 1993; Gascon et al., 1986) could be due to “the participants’ diagnosis of ADHD being made just before the beginning of their assessments” meaning that stimulant medication used may not have been titrated properly, this differs from the Tillery et al. (2000) study as participants had an existing diagnosis of ADHD, meaning that “medication dosages had already been titrated” (Tillery et al., 2000).
Review of the literature available relating to central auditory processing disorder (CAPD) shows that while there have been many studies conducted which have been able to provide insight into CAPD it is clear that further investigation needs to be undertaken.
The formulation of test batteries and standardized measures along with normative data is an important step to take in the advancement of understanding central auditory processing disorder. Many of the studies reviewed used similar methods along with small sample sizes preventing the results from being generalized to a greater population. From this it is clear that when conducting studies regarding CAPD, different methods need to be taken in order to produce “more conclusive findings” (Riccio et al., 1996) not only about CAPD including its diagnosis, but also about the relationship between CAPD and ADHD and how they differ. Due to limitations seen from the studies reviewed, a number of studies have questioned whether CAPD is “truly a distinct clinical entity” (Kamhi, 2011). Gomez et al. (1999) suggested that CAPD’s are more likely to be associated with learning disabilities than ADHD, proving that “CAPD and ADHD can occur as two distinct disorders” (Riccio et al., 1996). The use of stimulant medication to treat CAPD symptoms has achieved various results suggesting that further studies need to be undertaken to determine whether stimulant treatment is a reliable and beneficial treatment for CAPD. Keller et al. (2002) …show more content…
suggested that the use of subtypes for APD may be an important role in the differential diagnosis of APD as well as ADHD and other learning disabilities to prevent the occurrence of a misdiagnosis. Furthermore it is important to use a multidisciplinary approach to effectively and correctly diagnose CAPD, input from speech pathologists, audiologists, psychologists, teachers and parents should be taken into account to ensure a correct diagnosis. Not only does input from all these professionals help with obtaining a correct diagnosis it also assists with providing the correct treatment, whether that be from medication or other therapies. Without correct assessment procedures, differential diagnosis is not possible and the necessary intervention along with treatment and therapies cannot be determined (Riccio et al., 1996).
RESOURCES
American Speech-Language-Hearing Association. (2005). (Central) auditory processing disorders. Available from http://www.asha.org/policy/TR2005-00043.htm#sec1.3 -**
Cook, J. R., Mausback, T., Burd, L., Gascon, G. G., Slotnick, H. B., Patterson, B., Johnson, R. D., Hankey, B., & Reynolds, B. W. (1993). A preliminary study of the relationship between central auditory processing disorder and attention deficit disorder. Journal of Psychiatry & Neuroscience, 18(3), 130-137.
Emanual, D. (2002). The Auditory Processing Battery: Survey of Common Practices. Journal of the American Academy Audiology, 13:93-117.
Emanuel, D. C., Ficca, K. N., & Korczak, P. (2011). Survey of the diagnosis and management of auditory processing disorder. American Journal of Audiology, 20(1), 48-60.
Gascon, G.
G., Johnson, R. and Burd, L. (1986) Central Auditory Processing and Attention Deficit Disorders. Journal of Child Neurology, 1:27-33.
Gomez, R., & Condon, M. (1999). Central Auditory Processing Ability in Children with ADHD With and Without Learning Disabilities. Journal of Learning Disabilities, 32(2), 150-158.
Kamhi, A. G. (2011). What Speech-Language Pathologists Need to Know About Auditory Processing Disorder. Language, Speech and Hearing Services in Schools, 42:265-272.
Keller, W. D., & Tillery, K. L. (2002). Reliable Differential Diagnosis and Effective Management of Auditory Processing and Attention Deficit Hyperactivity Disorders. Seminars in Hearing, 23(4), 337-347.
Ludlow, C.L., Cudahey, E.A., Bassich, C., & Brown, G.L. (1983). Auditory processing skills of hyperactive, language impaired, and reading disabled boys. Central Auditory Processing Disorders. Baltimore, MD: University Park Press, 163-184.
Riccio, C. A., & Hynd, G. W. (1996). Relationship Between ADHD and Central Auditory Processing Disorder. School Psychology International, 17:235-252.
Tillery, K., Katz, J., Keller, W., (2000). Effects of methylphenidate (Ritalin™) on auditory performance in children with attention and auditory processing disorders. Journal of Speech, Language, and Hearing Research,
43:893–901.
Wilson, W. J., & Arnott, W. (2012). Using different criteria to diagnose (C)APD: how big a difference does it make? Journal of Speech, Language, and Hearing Research, doi:10.1044/1092-4388