a summary by Laurie Moses
Millions of children visit their doctor each year for a problemthat is commonly known as an ear infection, and countless otherssuffer silently because their symptoms are not recognized (Hemmer& Ratner, 1994). An inflammation of the middle ear and often themastoid process and Eustachian tube is termed otitis media and issecond only to the common cold as the most common illness of earlychildhood (Medley, Roberts, & Zeisel, 1995). Unlike the commoncold, however, incidents of otitis media are often accompanied bytemporary mild to moderate hearing loss and auditory deprivation(Finitzo, Gunnarson, & Clark, 1990). The American Academy ofPediatrics (as cited in Stewart, Anae, & Gipe, 1989) reports thatgrowing evidence indicates a correlation between middle-ear diseasewith hearing impairment and delays in the development of speech andcognitive skills. These issues are of concern to physicians,educators, and parents of children who suffer regular occurrences ofotitis media because the disease is most common during the period ofearly childhood when speech and language skills are developing(Roberts, Burchinal, Koch, Footo, & Henderson, 1988).
One aspect of the illness that should be of particular concern isthat some children suffer from otitis media without experiencingrecognizable symptoms (Paden, 1994). These children may, therefore,never see a physician and may never receive the medical interventionsnecessary to clear the infection and restore normal hearing. Althoughthe fluctuating hearing loss that accompanies the illness has longbeen recognized by researchers and other professionals in the field,recent research has indicated that the relationship between otitismedia and hearing loss may be more complex than was previouslyassumed (Paden, 1994). Research in the area has included examinationsof the effect of temporary hearing loss due to otitis media oncentral auditory processing, binaural interaction, hearing threshold,and speech and language development (Finitzo et al., 1990; Hall &Grose, 1994). In order to better understand these results, it isimportant to first examine the definition, epidemiology, and medicalmanagement of otitis media as well as the various methods forevaluating and defining hearing loss in children suffering from thedisease.
Otitis media can be classified into several categories includingacute otitis media and otitis media with effusion. Acute otitis mediarefers to a clinically identifiable infection of the middle earduring which the eardrum may appear red and swollen with puss-likefluid visible behind the eardrum. This type of ear infection has asudden onset and short duration of symptoms which may include fever,congestion, and pain (Medley et al., 1995). Otitis media witheffusion is also a relatively common childhood disease which ischaracterized by the accumulation of fluid in the middle ear space(Hall & Grose, 1994). This category has no acute symptoms but mayproduce some more subtle signs such as inattention and irritability(Medley et al., 1995). This condition often occurs secondary to anupper respiratory infection in children with poor Eustachian tubefunction (Hall & Grose, 1994). The fluid present in the middleear during an episode of otitis media with effusion isnon-infectious, and the illness itself is not contagious. It can,however, be contracted from bacteria, germs, and viruses that arethemselves easily spread in settings like daycares (Medley et al.,1995). A healthy Eustachian tube allows fluid to drain into the noseand throat, but when agents such as bacteria and germs spread up thetube from the mouth and nose into the middle ear, the Eustachian tubemay swell and close off the drainage pathway. This trapping of fluidis known as effusion and can remain even after the acute episode isresolved. In some children, the exchange between acute otitis mediaand otitis media with effusion is almost constant (Medley et al.,1995).
Although otitis media is not exclusively a childhood illness, itis extremely common in children between birth and two years of age(Hemmer & Ratner, 1994). Estimates of prevalence vary, but manystudies substantiate that most children do experience at least oneepisode of otitis media in early childhood, and at least one studyhas estimated that between 75% and 95% of all children are affected(Paden, 1994). Another study by Hardy and Fowler (as cited in Medleyet al., 1995) found that 17% of children in the United States betweenbirth and six years of age suffered from repeated ear infections.Otitis media peaks in occurrence between six and eighteen months ofage and declines after the third year (Paden, 1994). Many factorsseem to play a role in determining which children will have a higherincidence of the illness including family history of otitis media,attendance in group childcare, frequency of upper respiratoryinfections, bottle feeding in a reclined position, and frequentexposure to secondhand smoke (Medley et al., 1995). Also, accordingto Teele (as cited in Medley et al., 1995), early age at the time ofthe first occurrence and being male are also risk factors forrecurrent otitis media.
Medical intervention for children with otitis media differs basedon factors such as presentation and duration of symptoms and whetherthe infections are recurrent (Paden, 1994). The typical course oftreatment for acute symptoms is a ten-day course of antibiotics toeradicate the infection, but physicians often prescribe a longercourse for children who have frequent ear infections (Medley et al.,1995). Tympanostomy tubes can be surgically placed under the tympanicmembrane between the outer and middle ear to help drain the fluid andventilate the middle ear space. These tubes, which are sometimescalled pressure equalization tubes, can restore hearing immediatelyin most cases (Hall & Grose, 1994). Although these tubes may seemto be the answer to ending hearing loss due to otitis media witheffusion, Paden (1994) points out that since pain does not alwaysaccompany the infection, episodes may occur and persist without theparents' knowledge, and, therefore, these children never reach aphysician's office.
The hearing loss that accompanies middle ear effusion is generallymild to moderate and continues only as long as the fluid is presentin the middle ear (Roberts et al., 1988). The hearing loss is due tothe fluid pressing against and reducing movement of the eardrum sothat sound is muffled (Medley et al., 1995). The extent of thehearing deficit due to effusion varies greatly among children withotitis media; some children experience little or no loss while othershave quite large losses (Paden, 1994). The hearing loss suffered dueto otitis media typically averages about 25 dB HL but can range fromno loss to as much as 50 dB HL (Hall & Grose, 1994). Concernusually arises when a child who experienced a first onset of effusionprior to twelve months of age experiences more than three episodesper year for multiple years and when these episodes are bilateral andreduce the hearing threshold by as much as 20 - 40 dB (Hemmer &Ratner, 1994). In rare cases permanent sensorineural hearing loss canoccur if the middle ear infection spreads into the inner ear (Medleyet al., 1995).
Diagnosis of otitis media with effusion is determined for thepurpose of medical intervention and research by use of pneumaticotoscopy and tympanometry (Paden, 1994). The illness is diagnosed byotoscopy when middle ear fluid is detected or when the mobility ofthe tympanic membrane is absent or markedly reduced (Roberts et al.,1988). Tympanometry is used to corroborate the diagnosis of effusion,and a Type B tympanogram with a flat or rising shape is considered tobe an accurate indication of the infection (Peters, Grievink, vanBon, & Schilder, 1994).
The majority of research on otitis media during the past decadehas focused on the effects of temporary hearing loss on thedeveloping language skills of children before the age of three(Stewart et al., 1989; Medley et al., 1995). One study examined agroup of 3-to-8 year olds who had histories of chronic otitis mediawith effusion and had all experienced initial onset of the illnessprior to age 18 months (Roberts et al., 1988). The study found that,although these children did misarticulate more consonants on theTemplin-Darley Screening Test than children without otitis mediahistories, both groups committed errors on the same sounds (Robertset al., 1988). Peters et al. (1994) also points out several studiesthat suggest a relationship between educational achievement andoccurrence of otitis media. A few of these studies also suggest thatthe fluctuating hearing losses may actually have a more negativeeffect on speech and language than would a continuous mild tomoderate loss (Peters et al., 1994). Additional studies, includingPeters et al.(1994), also indicate that otitis media is highlycorrelated with increased levels of hearing loss.
Other studies on the effects of otitis media on hearing havefocused on the effects of early auditory deprivation on centralauditory processing, development of auditory neurons, anddiscrimination of sounds (Finitzo et al., 1990; Paden, 1994). Finitzoet al. (1990) also points out studies that seem to indicate thathearing loss due to middle ear effusion causes deficits in processingspeech and non-speech aspects of the auditory signal. Another studyfound that children with central auditory processing disorders havedifficulty with discriminating foreground and background noise,problems with auditory attention, and a reduced ability to sequenceauditory information (Finitzo et al., 1990). With respect to problemswith foreground and background discrimination, one researcher pointsout that similarities between foreground and background noise causegreater difficulties for infants than adults under normalcircumstances and would be a particular problem if the infant wereexperiencing mild hearing loss (Paden, 1994). Some auditorydeprivation studies have been conducted on animals in order to assessthe anatomical and physiological changes due to sound deprivation. Inone such study, researchers found that early auditory deprivation inmice reduced the speed and duration of the central auditory responsescaused by high frequency sounds (Finitzo et al., 1990). Blatchley etal. (as cited in Finitzo et al., 1990) concluded from another studyof mice that auditory stimulation is important during certaincritical periods of development in order to maintain a normal cellsize in auditory neurons.
Current research on otitis media with effusion and hearing lossappears to be moving in the direction of examining the effects of afluctuating mild to moderate hearing deficit on a child's ability tosegregate sounds from competing noise adequately. Results of onestudy indicate that there may be a reduced ability for auditorysegregation in children with otitis media histories but that moreresearch is necessary in the area (Hall & Grose, 1994). Binauralfusion tests from the Willeford battery also suggest a lossintegration especially in the presence of background noise that issimilar to a speech message (Finitzo et al., 1990). Monauraldeprivation in rats during the critical period for developingbinaural interaction resulted in a complete loss of binauralinteraction due to absence of ipsilateral suppression ofcontralateral activity at the deprived ear (Finitzo et al., 1990).Finitzo et al. (1990) concluded that this greater than normalsuppression resulted in cells becoming more responsive to stimulifrom the non-deprived ear. Findings such as these will undoubtedlylead to more research on auditory deprivation and its effect onbinaural interaction in children with histories of otitis media.
Many current research studies are seeking ways to overcome some ofthe problems that have existed in past attempts to assess the effectsof recurrent effusion on hearing. One past problem has been the useof retrospective studies to examine speech difficulties caused bytemporary elevation of hearing thresholds due to effusion (Paden,1994). These types of studies often rely on parental recall which,even when excellent, cannot include those cases that involved silentsymptoms. Unfortunately, prospective studies that require regularexamination of children's ears to determine when effusion is presentmay cause a different research problem because they identifyinfections that may have gone unnoticed in a real world situation.Researchers are currently seeking ways to work around these issues.Another problem with past research has been the failure to useuniform methods in testing hearing. According to Paden (1994), thismay account for some disagreement in conclusions from differentstudies. Researchers also point out two other gaps in previousresearch that will likely be important future topics. These includemore extensive studies of hearing thresholds of children withrecurrent otitis media with effusion during symptom free periods(Paden, 1994) and more studies that distinguish between unilateraland bilateral effusion and compare the consequences of the two forms(Peters et al., 1994).
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Hall, J.W., & Grose, J.H. (1994). Effect of otitis media witheffusion comodulation masking release in children. Journal ofSpeech and Hearing Research, 37(6), 1441-49.
Hemmer, V.H. & Ratner, N.B. (1994). Communicative developmentin twins with discordant histories of recurrent otitis media.Journal of Communication Disorders, 27(2), 91-106.
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Paden, E.P. (1994). Otitis media and disordered phonologies: Someconcerns and cautions. Topics in Language Disorders, 14(2),72-83.
Peters, S.A., Grievink, E.H., van Bon, W.H., & Schilder, A.G.(1994). The effects of early bilateral otitis media with effusion oneducational attainment: A prospective cohort study. Journal ofLearning Disabilities, 27(2), 111-121.
Roberts, J.E., Burchinal, M.R., Koch, M.A., Footo, M.M., &Henderson, F.W. (1988). Otitis media in early childhood and itsrelationship to later phonological development. Journal of Speechand Hearing Disorders, 53(4), 424-432.
Stewart, J.L., Anae, A.P., & Gipe, P.N. (1989). PacificIslander children: Prevalence of hearing loss and middle ear disease.Topics in Language Disorders, 9(3), 76-83.