G Model
PEDOT-7019; No. of Pages 3 International Journal of Pediatric Otorhinolaryngology xxx (2014) xxx–xxx
Contents lists available at ScienceDirect
International Journal of Pediatric Otorhinolaryngology journal homepage: www.elsevier.com/locate/ijporl
Hearing loss in the shaken baby syndrome Musaed Alzahrani a, Justine Ratelle b, Oren Cavel a, Marie Laberge-Malo c, Issam Saliba d,* a
Division of Otorhinolaryngology, University of Montreal, Montreal, QC, Canada Department of Audiology, Sainte-Justine University Hospital, 3175 Chemin de la Coˆte-Sainte-Catherine, Montreal, QC H3T 1C5, Canada c Department of Pediatrics, Sainte-Justine University Hospital (CHUSJ), 3175 Chemin de la Coˆte-Sainte-Catherine, Montreal, QC H3T 1C5, Canada d Division of Otorhinolaryngology Head & Neck Surgery, University of Montreal, Otology and Neurotology, Sainte-Justine University Hospital Center (CHUSJ) and University of Montreal Hospital Center (CHUM), Montreal, QC, Canada b
A R T I C L E I N F O
A B S T R A C T
Article history: Received 29 December 2013 Received in revised form 15 February 2014 Accepted 17 February 2014 Available online xxx
Objectives: To evaluate hearing in children diagnosed with shaken baby syndrome. Methods: A retrospective study conducted in a pediatric tertiary care center between 2006 and 2012. Children diagnosed with shaken baby syndrome were included for hearing evaluation by conventional audiometry, distortion product otoacoustic emissions and auditory brainstem responses. Results: Twenty-eight children were included (22 boys and 6 girls). The mean age of children at presentation was 8 months (range 1–26 months) and the mean delay before audiometric evaluation was 30 months (range 1–87 months). One child was diagnosed as having a moderate sensorineural hearing loss. The tympanic membrane mobility was normal (type A) for both ears in 22 children, one child had a reduced tympanic mobility in one ear, two children had a negative pressure, one child had a functional trans-tympanic tube and test was not performed in 2 patients. Conclusion: This is the first study reporting hearing loss as a possible result of shaken baby syndrome. However, further studies with larger number of children would be preferable. We recommend hearing evaluation for these children to rule out hearing loss. ß 2014 Published by Elsevier Ireland Ltd.
Keywords: Shaken baby syndrome Hearing loss Non-accidental injury DPOAE ABR Audiometry
1. Introduction Shaken baby syndrome (SBS) is recognized as a non-accidental head trauma due violent infant shaking [1]. The first description of such infantile maltreatment was reported in 1971 [2]. It is mostly characterized by subdural hemorrhage (SDH), retinal hemorrhage (RH), and encephalopathy [3–10]. Children less than 1 year, with a peak of 10–16 weeks, are at most risk in a non-witnessed situation and by a sole career [11]. Cranial injuries as well as the ophthalmologic manifestations are widely described in the literature [2,4,5,7,8]. Mortality of SBS can reach 30% and another 30–50% might experience cognitive or other neurological problems [12]. Post mortem histological studies have shown fresh bleeding in the dura in 36 of 50 inflicted infants [13]. Of those, 75% (27 of 36) had severe hypoxia clinically. RHs are reported between 50% and 100% of affected children [14]. It is considered by some pediatrician in the presence of other
* Corresponding author at: Sainte-Justine University Hospital Center (CHUSJ), 3175, Coˆte Sainte-Catherine, Department of Otolaryngology, Montreal, QC H3T 1C5, Canada. Tel.: +1 514 345 4857; fax: +1 514 737 4822. E-mail address: [email protected] (I. Saliba).
non-accidental cranial injuries as diagnostic for child abuse [5]. Increased arterial or venous pressure due to intracranial hemorrhage or carotid arteries occlusion are the main theories [5]. However, to our knowledge, auditory affection by such infliction is not yet properly investigated in the literature. The aim of the study is to evaluate the hearing outcomes in children diagnosed with SBS by means of conventional audiometry, distortion products otoacoustic emissions and auditory brainstem responses. 2. Methods This study was conducted by reviewing retrospectively all children charts diagnosed as SBS between 2006 and 2012 at our pediatric tertiary care center. All children were younger than 3 years old. The study was approved by our Institutional Research Ethics Board and follows the standards of our Institutional Ethics Committee. Children diagnosed as victims of such infliction were referred for audiologic evaluation. Exclusion criteria include: the presence of genetic syndrome, history of ototoxicity, family history of hearing loss and history of neonatal complications (infection, hyperbilirubinemia, very light weight and respiratory problems). Otomicroscopic examination was performed by an otolaryngologist before all audiometric tests for cleaning and to rule out possible tympanic
http://dx.doi.org/10.1016/j.ijporl.2014.02.018 0165-5876/ß 2014 Published by Elsevier Ireland Ltd.
Please cite this article in press as: M. Alzahrani, et al., Hearing loss in the shaken baby syndrome, Int. J. Pediatr. Otorhinolaryngol. (2014), http://dx.doi.org/10.1016/j.ijporl.2014.02.018
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PEDOT-7019; No. of Pages 3 M. Alzahrani et al. / International Journal of Pediatric Otorhinolaryngology xxx (2014) xxx–xxx
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Table 1 Number of test performed for audiometric evaluation. CA: conventional audiometry, DPOAE: distortion products otoacoustic emissions, ABR: auditory brainstem responses.
membrane injuries or otitis media. Audiologic evaluation including: conventional audiometry, distortion products oto-acoustic emissions, and auditory brainstem responses, is then performed by a licensed and certified audiologist. Immittancemetry was obtained using a GSI Tympstar (Grason-Stadler). The peak compliance, the peak pressure and the external auditory canal volume were qualified using the Jerger 1970 norm to determine the tympanic membrane movement. 2.1. Conventional audiometric test Conventional audiometric testing was performed in a soundtreated booth using either an interacoustic clinical audiometer (Model AC40; Assens, Denmark) or a Maico 40/41 portable clinical audiometer (Eden Prairie, Minnesota). The equipment was calibrated in accordance with the guidelines of the American speech-language-hearing association following American national standards institute specifications (1996). Responses were measured at octave frequencies from 500 Hz to 4000 Hz for bone conduction (BC) thresholds and 500–8000 Hz for air conduction (AC) thresholds on monaural and/or binaural situations. According to the age and cooperation of the child, responses were measure by conventional audiometry, conditioned play audiometry (CPA), or visual reinforcement audiometry (VRA). 2.2. Distortion products otoacoustic emissions (DPOAE) A clinical DPOAE system, Otodynamics Echo port ILO 288 (Otodynamics Ltd., Hatfield, UK) was employed to measure responses at frequencies 1, 1.4, 2, 2.8, 4 and 6 kHz in both ears. The test was performed in silent environment at a sound treated room. DPOAE responses were measured in response to two primary frequencies of f1 and f2 presented at 65 and 55 db SPL, respectively, and the frequency ratio (f2/f1) was constant at 1.2. A noise to signal ratio greater than 6 dB was considered a present response.
Type of test
Number of children
CA alone DPOAE and ABR DPOAE and CA DPOAE, ABR, CA
5 3 18 2
Total
28
2.3. Auditory brainstem responses (ABR) ABRs were recorded using a Biologic Navigator Pro system (BioLogic Systems Corp., Mundelein, IL) with the child in the supine position in a quiet room. Monaural tone bursts in alternating polarity were presented in an ER-3A insert earphone (Etymotic Research, Elk Grove, IL) at a repetition rate of 36.1 at 500 Hz and 39.1 from 1000 to 4000 Hz. The lowest intensity level at which a detectable and repeatable-wave V response was recorded. 3. Results From 2006 to 2012, 43 children were diagnosed as victims of SBS. Five children died during their hospitalization and 10 others could not be reached or refused the audiologic evaluation. Twentyeight children were evaluated for hearing impairment including 22 boys and 6 girls. The mean age of children at time of presentation was 8 months (range 1–26 months) and the mean delay before audiometric evaluation was 30 months (range 1–87 months). Immittancemetry was available for 26 out of 28 children. The tympanic membrane mobility was normal (type A) for both ears in 22 children, one child had a reduced tympanic mobility in one ear, two children had a negative pressure, and one child had a functional trans-tympanic tube.
Table 2 Children’s data and audiometric results. CA: conventional audiometry, DPOAE: distortion products oto-acoustic emissions, ABR: auditory brainstem responses, Lt: left ear, Rt: right ear, F: female, M: male, PTA: pure tone audiometry, (+): present, ( ): absent. Patient number
Sex
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28
F M M M M M M F F F M M F M M M M M M M M M M M M M M F
Age at diagnosis (months)
Delay before evaluation (months)
DPOAE Rt
Lt
ABR (dB)
3 3 6 26 11 5 3 17 1 6 2 13 4 3 10 12 20 5 13 10 3 11 21 1 8 2 1 3
51 75 12 2 73 4 8 2 21 40 26 14 16 56 13 21 87 41 1 64 53 1 1 10 19 69 30 13
+
+
+ + + +
+ + + +
+
+
+
+
Rt
Conventional audiometry (PTA) (dB) Lt
Rt 7.5 5
6.25
60 15
8.75 18.75 15 52.5
50 15 7.5
15 20
+ + + + + + + + + + + + + + +
Binaural
7.5 5 16.25 17.5
6.25
+ + + + + + + + + + + + + + +
Lt
15
15
15
15
7.5
15 8.75 15
11.25 7.5
12.5 6.25
6.25 8.75
13.75 10
15
10
20 18.75 20 21.25
10
7.5 10
6.25 11.25 17.5
Please cite this article in press as: M. Alzahrani, et al., Hearing loss in the shaken baby syndrome, Int. J. Pediatr. Otorhinolaryngol. (2014), http://dx.doi.org/10.1016/j.ijporl.2014.02.018
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PEDOT-7019; No. of Pages 3 M. Alzahrani et al. / International Journal of Pediatric Otorhinolaryngology xxx (2014) xxx–xxx
Twenty-three children were evaluated by DPOAE, 3 of them were evaluated additionally by ABRs while 5 children were evaluated by conventional audiometry only (Table 1). One child, 17 months old, was diagnosed as having a moderate sensorineural hearing loss (SNHL) confirmed by ABRs and conventional audiometry. Details of children age and delay of evaluation as well as the used tests are summarized in Table 2. 4. Discussion In the present study, one child was found to have a moderate SNHL out of 28 children diagnosed with SBS and evaluated for hearing loss. SBS is mostly encountered in children younger than one year and boys are slightly more affected [11]. Although the triad of RH, SDH and encephalopathy are the classical presentations in this pathology, other serious injuries can be encountered, including external head trauma, cervical and skeletal fractures as well as cutaneous bruising [15,16]. However, up to 40% of victims might present with a non-specific symptoms in which a high index of suspicion is required for diagnosis [16]. In a Canadian national study, mortality was reported in 19% of 364 children recruited from 11 pediatric centers (including ours) between 1988 and 1998 [16]. However, we found no much data on hearing loss incidence in this pathology. Mechanism and pathology of SBS were described in 1971 by Guthkelch as a result of a whiplash or shaking injury [2]. This injury may result in a rotational acceleration/deceleration forces and probably shearing the bridging veins leading to subdural hematoma [2]. However, this theory has been studied by other authors who simulated shaking in experimental models and concluded that shaking did not generate enough forces to cause subdural hematoma [17,18]. Cochlear concussion may results from a blow to the head not strong enough to cause a fracture. It may, however, produce mild to total hearing loss. This is because of the resultant tears of the membranous labyrinth, which may involve the vestibular structures as well as the cochlea. It seems that the force produced by shaking the baby is not strong enough to cause such cochlear tears. Indeed, The American academy of pediatrician recommended in 2009 to drop the term SBS and adopted the term ‘‘Non-accidental Head Injury’’ because the shaking was considered as a misnomer of this condition [19]. Hypoxia has been also described recently as a possible mechanism to explain the presenting triad. Prolonged hypoxia from time of child collapse to resuscitation may explain the encephalopathy [11]. It was also found to be significantly associated with RH [11]. Cohen and colleagues have demonstrated in post mortem studies that hypoxia was frequently associated with SDH [20]. Data about the real incidence of hearing loss in SBS is lacking. It might be simply because we can not be certain that hearing loss did not exist prior to the infliction in this young category of victims. Also, hearing evaluation was not reported in any of the previously published articles addressing this subject. Hearing loss in the general population occurs approximately in 1–3 infants per 1000 [21]. However, conducting a comparative study is difficult due to the relatively rare cases of the SBS. In this study, one SBS child had a moderate SNHL. However, this finding should be interpreted with precaution because we did not have previous hearing evaluation to rule out congenital hearing loss. Nevertheless, it should alert concerned health care providers to the possibility of hearing deterioration in children victimized of SBS. Experimental studies have shown small blood vessel damage in prolonged ischemia [22]. Also, congenital hearing loss has been noticed in prolonged and difficult labor and delivery leading probably to an ischemic effect of the small labyrinthine arteries. The main limitations of this study are the small number of children and in some, the long delay between the infliction and the
3
audiometric evaluation. In addition, the long-term follow up of those children is not evaluated. Despite that, this is the first study to predict hearing loss in SBS. Inspired of our findings, we believe that all children victimized of this infliction should be evaluated for hearing loss as early as they are stabilized to avoid unintentional neglect and most important for early detection and proper rehabilitation. In addition, the implementation of universal newborn hearing-screening programs before hospital discharge will be helpful as a reference test for children in case of later on infliction. The universal newborn hearing-screening program before hospital discharge was started in our institution 2 years ago. 5. Conclusion This is the first report studying a correlation between hearing loss and shaken baby syndrome. Hearing loss may be a result of SBS. However, further studies with larger number of children would be preferable. However, we recommend a universal newborn hearing screening programs before hospital discharge and a hearing evaluation for all SBS children to rule out hearing loss. References [1] M.A. Mraz, The physical manifestations of shaken baby syndrome, J. Forensic Nurs. 5 (1) (2009) 26–30. [2] A.N. Guthkelch, Infantile subdural haematoma and its relationship to whiplash injuries, Br. Med. J. 2 (May (5759)) (1971) 430–431. [3] W. Squier, Shaken baby syndrome: the quest for evidence, Dev. Med. Child Neurol. 50 (January (1)) (2008) 10–14. [4] J.D. Kivlin, Manifestations of the shaken baby syndrome, Curr. Opin. Ophthalmol. 12 (June (3)) (2001) 158–163. [5] A.V. Levin, Retinal hemorrhage in abusive head trauma, Pediatrics 126 (November (5)) (2010) 961–970. [6] J. Matschke, K. Pu¨schel, M. Glatzel, Ocular pathology in shaken baby syndrome and other forms of infantile non-accidental head injury, Int. J. Legal Med. 123 (May (3)) (2009) 189–197. [7] Y. Morad, T. Wygnansky-Jaffe, A.V. Levin, Retinal haemorrhage in abusive head trauma, Clin. Exp. Ophthalmol. 38 (July (5)) (2010) 514–520. [8] B.M. Togioka, M.A. Arnold, M.A. Bathurst, S.M. Ziegfeld, R. Nabaweesi, P.M. Colombani, et al., Retinal hemorrhages and shaken baby syndrome: an evidence-based review, J. Emerg. Med. 37 (July (1)) (2009) 98–106. [9] K. Tsao, M. Kazlas, J.J. Weiter, Ocular injuries in shaken baby syndrome, Int. Ophthalmol. Clin. 42 (3) (2002) 145–155. [10] T. Wygnanski-Jaffe, Y. Morad, A.V. Levin, Pathology of retinal hemorrhage in abusive head trauma, Forensic Sci. Med. Pathol. 5 (December (4)) (2009) 291–297. [11] W. Squier, The, ‘‘Shaken Baby’’ syndrome: pathology and mechanisms, Acta Neuropathol. (Berl.) 122 (November (5)) (2011) 519–542. [12] L. Altimier, Shaken baby syndrome, J. Perinat. Neonatal Nurs. 22 (January–March (1)) (2008) 68–76 (quiz 77–78). [13] J.F. Geddes, R.C. Tasker, A.K. Hackshaw, C.D. Nickols, G.G.W. Adams, H.L. Whitwell, et al., Dural haemorrhage in non-traumatic infant deaths: does it explain the bleeding in shaken baby syndrome? Neuropathol. Appl. Neurobiol. 29 (February (1)) (2003) 14–22. [14] Y. Morad, Y.M. Kim, D.C. Armstrong, D. Huyer, M. Mian, A.V. Levin, Correlation between retinal abnormalities and intracranial abnormalities in the shaken baby syndrome, Am. J. Ophthalmol. 134 (September (3)) (2002) 354–359. [15] A.C. Lee, K.T. So, D. Fong, S.H. Luk, The shaken baby syndrome: review of 10 cases, Hong Kong Med. J. 5 (December (4)) (1999) 337–341. [16] W.J. King, M. Mackay, A. Sirnick, Canadian Shaken Baby Study Group, Shaken baby syndrome in Canada: clinical characteristics and outcomes of hospital cases, Can. Med. Assoc. J. 168 (January (2)) (2003) 155–159. [17] A.C. Duhaime, C.W. Christian, L.B. Rorke, R.A. Zimmerman, Nonaccidental head injury in infants – the shaken-baby syndrome, N. Engl. J. Med. 338 (June (25)) (1998 Jun 18) 1822–1829. [18] M.T. Prange, B. Coats, A.-C. Duhaime, S.S. Margulies, Anthropomorphic simulations of falls, shakes, and inflicted impacts in infants, J. Neurosurg. 99 (July (1)) (2003) 143–150. [19] C.W. Christian, R. Block, Abusive head trauma in infants and children, Pediatrics 123 (May (5)) (2009) 1409–1411. [20] M.C. Cohen, A. Sprigg, E.H. Whitby, Subdural hemorrhage, intradural hemorrhage and hypoxia in the pediatric and perinatal post mortem: are they related? An observational study combining the use of post mortem pathology and magnetic resonance imaging, Forensic Sci. Int. 200 (July (1–3)) (2010) 100–107. [21] A.K. Biswas, S.C. Goswami, D.K. Baruah, R. Tripathy, The potential risk factors and the identification of hearing loss in infants, Ind. J. Otolaryngol. Head Neck Surg. 64 (September (3)) (2012) 214–217. [22] H. Lu, J. Zhao, M. Li, Y. Cheng, Y. Li, X. You, et al., Microvessel changes after postischemic benign and malignant hyperemia: experimental study in rats, BMC Neurol. 10 (2010) 24.
Please cite this article in press as: M. Alzahrani, et al., Hearing loss in the shaken baby syndrome, Int. J. Pediatr. Otorhinolaryngol. (2014), http://dx.doi.org/10.1016/j.ijporl.2014.02.018
PEDOT-7019; No. of Pages 3 International Journal of Pediatric Otorhinolaryngology xxx (2014) xxx–xxx
Contents lists available at ScienceDirect
International Journal of Pediatric Otorhinolaryngology journal homepage: www.elsevier.com/locate/ijporl
Hearing loss in the shaken baby syndrome Musaed Alzahrani a, Justine Ratelle b, Oren Cavel a, Marie Laberge-Malo c, Issam Saliba d,* a
Division of Otorhinolaryngology, University of Montreal, Montreal, QC, Canada Department of Audiology, Sainte-Justine University Hospital, 3175 Chemin de la Coˆte-Sainte-Catherine, Montreal, QC H3T 1C5, Canada c Department of Pediatrics, Sainte-Justine University Hospital (CHUSJ), 3175 Chemin de la Coˆte-Sainte-Catherine, Montreal, QC H3T 1C5, Canada d Division of Otorhinolaryngology Head & Neck Surgery, University of Montreal, Otology and Neurotology, Sainte-Justine University Hospital Center (CHUSJ) and University of Montreal Hospital Center (CHUM), Montreal, QC, Canada b
A R T I C L E I N F O
A B S T R A C T
Article history: Received 29 December 2013 Received in revised form 15 February 2014 Accepted 17 February 2014 Available online xxx
Objectives: To evaluate hearing in children diagnosed with shaken baby syndrome. Methods: A retrospective study conducted in a pediatric tertiary care center between 2006 and 2012. Children diagnosed with shaken baby syndrome were included for hearing evaluation by conventional audiometry, distortion product otoacoustic emissions and auditory brainstem responses. Results: Twenty-eight children were included (22 boys and 6 girls). The mean age of children at presentation was 8 months (range 1–26 months) and the mean delay before audiometric evaluation was 30 months (range 1–87 months). One child was diagnosed as having a moderate sensorineural hearing loss. The tympanic membrane mobility was normal (type A) for both ears in 22 children, one child had a reduced tympanic mobility in one ear, two children had a negative pressure, one child had a functional trans-tympanic tube and test was not performed in 2 patients. Conclusion: This is the first study reporting hearing loss as a possible result of shaken baby syndrome. However, further studies with larger number of children would be preferable. We recommend hearing evaluation for these children to rule out hearing loss. ß 2014 Published by Elsevier Ireland Ltd.
Keywords: Shaken baby syndrome Hearing loss Non-accidental injury DPOAE ABR Audiometry
1. Introduction Shaken baby syndrome (SBS) is recognized as a non-accidental head trauma due violent infant shaking [1]. The first description of such infantile maltreatment was reported in 1971 [2]. It is mostly characterized by subdural hemorrhage (SDH), retinal hemorrhage (RH), and encephalopathy [3–10]. Children less than 1 year, with a peak of 10–16 weeks, are at most risk in a non-witnessed situation and by a sole career [11]. Cranial injuries as well as the ophthalmologic manifestations are widely described in the literature [2,4,5,7,8]. Mortality of SBS can reach 30% and another 30–50% might experience cognitive or other neurological problems [12]. Post mortem histological studies have shown fresh bleeding in the dura in 36 of 50 inflicted infants [13]. Of those, 75% (27 of 36) had severe hypoxia clinically. RHs are reported between 50% and 100% of affected children [14]. It is considered by some pediatrician in the presence of other
* Corresponding author at: Sainte-Justine University Hospital Center (CHUSJ), 3175, Coˆte Sainte-Catherine, Department of Otolaryngology, Montreal, QC H3T 1C5, Canada. Tel.: +1 514 345 4857; fax: +1 514 737 4822. E-mail address: [email protected] (I. Saliba).
non-accidental cranial injuries as diagnostic for child abuse [5]. Increased arterial or venous pressure due to intracranial hemorrhage or carotid arteries occlusion are the main theories [5]. However, to our knowledge, auditory affection by such infliction is not yet properly investigated in the literature. The aim of the study is to evaluate the hearing outcomes in children diagnosed with SBS by means of conventional audiometry, distortion products otoacoustic emissions and auditory brainstem responses. 2. Methods This study was conducted by reviewing retrospectively all children charts diagnosed as SBS between 2006 and 2012 at our pediatric tertiary care center. All children were younger than 3 years old. The study was approved by our Institutional Research Ethics Board and follows the standards of our Institutional Ethics Committee. Children diagnosed as victims of such infliction were referred for audiologic evaluation. Exclusion criteria include: the presence of genetic syndrome, history of ototoxicity, family history of hearing loss and history of neonatal complications (infection, hyperbilirubinemia, very light weight and respiratory problems). Otomicroscopic examination was performed by an otolaryngologist before all audiometric tests for cleaning and to rule out possible tympanic
http://dx.doi.org/10.1016/j.ijporl.2014.02.018 0165-5876/ß 2014 Published by Elsevier Ireland Ltd.
Please cite this article in press as: M. Alzahrani, et al., Hearing loss in the shaken baby syndrome, Int. J. Pediatr. Otorhinolaryngol. (2014), http://dx.doi.org/10.1016/j.ijporl.2014.02.018
G Model
PEDOT-7019; No. of Pages 3 M. Alzahrani et al. / International Journal of Pediatric Otorhinolaryngology xxx (2014) xxx–xxx
2
Table 1 Number of test performed for audiometric evaluation. CA: conventional audiometry, DPOAE: distortion products otoacoustic emissions, ABR: auditory brainstem responses.
membrane injuries or otitis media. Audiologic evaluation including: conventional audiometry, distortion products oto-acoustic emissions, and auditory brainstem responses, is then performed by a licensed and certified audiologist. Immittancemetry was obtained using a GSI Tympstar (Grason-Stadler). The peak compliance, the peak pressure and the external auditory canal volume were qualified using the Jerger 1970 norm to determine the tympanic membrane movement. 2.1. Conventional audiometric test Conventional audiometric testing was performed in a soundtreated booth using either an interacoustic clinical audiometer (Model AC40; Assens, Denmark) or a Maico 40/41 portable clinical audiometer (Eden Prairie, Minnesota). The equipment was calibrated in accordance with the guidelines of the American speech-language-hearing association following American national standards institute specifications (1996). Responses were measured at octave frequencies from 500 Hz to 4000 Hz for bone conduction (BC) thresholds and 500–8000 Hz for air conduction (AC) thresholds on monaural and/or binaural situations. According to the age and cooperation of the child, responses were measure by conventional audiometry, conditioned play audiometry (CPA), or visual reinforcement audiometry (VRA). 2.2. Distortion products otoacoustic emissions (DPOAE) A clinical DPOAE system, Otodynamics Echo port ILO 288 (Otodynamics Ltd., Hatfield, UK) was employed to measure responses at frequencies 1, 1.4, 2, 2.8, 4 and 6 kHz in both ears. The test was performed in silent environment at a sound treated room. DPOAE responses were measured in response to two primary frequencies of f1 and f2 presented at 65 and 55 db SPL, respectively, and the frequency ratio (f2/f1) was constant at 1.2. A noise to signal ratio greater than 6 dB was considered a present response.
Type of test
Number of children
CA alone DPOAE and ABR DPOAE and CA DPOAE, ABR, CA
5 3 18 2
Total
28
2.3. Auditory brainstem responses (ABR) ABRs were recorded using a Biologic Navigator Pro system (BioLogic Systems Corp., Mundelein, IL) with the child in the supine position in a quiet room. Monaural tone bursts in alternating polarity were presented in an ER-3A insert earphone (Etymotic Research, Elk Grove, IL) at a repetition rate of 36.1 at 500 Hz and 39.1 from 1000 to 4000 Hz. The lowest intensity level at which a detectable and repeatable-wave V response was recorded. 3. Results From 2006 to 2012, 43 children were diagnosed as victims of SBS. Five children died during their hospitalization and 10 others could not be reached or refused the audiologic evaluation. Twentyeight children were evaluated for hearing impairment including 22 boys and 6 girls. The mean age of children at time of presentation was 8 months (range 1–26 months) and the mean delay before audiometric evaluation was 30 months (range 1–87 months). Immittancemetry was available for 26 out of 28 children. The tympanic membrane mobility was normal (type A) for both ears in 22 children, one child had a reduced tympanic mobility in one ear, two children had a negative pressure, and one child had a functional trans-tympanic tube.
Table 2 Children’s data and audiometric results. CA: conventional audiometry, DPOAE: distortion products oto-acoustic emissions, ABR: auditory brainstem responses, Lt: left ear, Rt: right ear, F: female, M: male, PTA: pure tone audiometry, (+): present, ( ): absent. Patient number
Sex
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28
F M M M M M M F F F M M F M M M M M M M M M M M M M M F
Age at diagnosis (months)
Delay before evaluation (months)
DPOAE Rt
Lt
ABR (dB)
3 3 6 26 11 5 3 17 1 6 2 13 4 3 10 12 20 5 13 10 3 11 21 1 8 2 1 3
51 75 12 2 73 4 8 2 21 40 26 14 16 56 13 21 87 41 1 64 53 1 1 10 19 69 30 13
+
+
+ + + +
+ + + +
+
+
+
+
Rt
Conventional audiometry (PTA) (dB) Lt
Rt 7.5 5
6.25
60 15
8.75 18.75 15 52.5
50 15 7.5
15 20
+ + + + + + + + + + + + + + +
Binaural
7.5 5 16.25 17.5
6.25
+ + + + + + + + + + + + + + +
Lt
15
15
15
15
7.5
15 8.75 15
11.25 7.5
12.5 6.25
6.25 8.75
13.75 10
15
10
20 18.75 20 21.25
10
7.5 10
6.25 11.25 17.5
Please cite this article in press as: M. Alzahrani, et al., Hearing loss in the shaken baby syndrome, Int. J. Pediatr. Otorhinolaryngol. (2014), http://dx.doi.org/10.1016/j.ijporl.2014.02.018
G Model
PEDOT-7019; No. of Pages 3 M. Alzahrani et al. / International Journal of Pediatric Otorhinolaryngology xxx (2014) xxx–xxx
Twenty-three children were evaluated by DPOAE, 3 of them were evaluated additionally by ABRs while 5 children were evaluated by conventional audiometry only (Table 1). One child, 17 months old, was diagnosed as having a moderate sensorineural hearing loss (SNHL) confirmed by ABRs and conventional audiometry. Details of children age and delay of evaluation as well as the used tests are summarized in Table 2. 4. Discussion In the present study, one child was found to have a moderate SNHL out of 28 children diagnosed with SBS and evaluated for hearing loss. SBS is mostly encountered in children younger than one year and boys are slightly more affected [11]. Although the triad of RH, SDH and encephalopathy are the classical presentations in this pathology, other serious injuries can be encountered, including external head trauma, cervical and skeletal fractures as well as cutaneous bruising [15,16]. However, up to 40% of victims might present with a non-specific symptoms in which a high index of suspicion is required for diagnosis [16]. In a Canadian national study, mortality was reported in 19% of 364 children recruited from 11 pediatric centers (including ours) between 1988 and 1998 [16]. However, we found no much data on hearing loss incidence in this pathology. Mechanism and pathology of SBS were described in 1971 by Guthkelch as a result of a whiplash or shaking injury [2]. This injury may result in a rotational acceleration/deceleration forces and probably shearing the bridging veins leading to subdural hematoma [2]. However, this theory has been studied by other authors who simulated shaking in experimental models and concluded that shaking did not generate enough forces to cause subdural hematoma [17,18]. Cochlear concussion may results from a blow to the head not strong enough to cause a fracture. It may, however, produce mild to total hearing loss. This is because of the resultant tears of the membranous labyrinth, which may involve the vestibular structures as well as the cochlea. It seems that the force produced by shaking the baby is not strong enough to cause such cochlear tears. Indeed, The American academy of pediatrician recommended in 2009 to drop the term SBS and adopted the term ‘‘Non-accidental Head Injury’’ because the shaking was considered as a misnomer of this condition [19]. Hypoxia has been also described recently as a possible mechanism to explain the presenting triad. Prolonged hypoxia from time of child collapse to resuscitation may explain the encephalopathy [11]. It was also found to be significantly associated with RH [11]. Cohen and colleagues have demonstrated in post mortem studies that hypoxia was frequently associated with SDH [20]. Data about the real incidence of hearing loss in SBS is lacking. It might be simply because we can not be certain that hearing loss did not exist prior to the infliction in this young category of victims. Also, hearing evaluation was not reported in any of the previously published articles addressing this subject. Hearing loss in the general population occurs approximately in 1–3 infants per 1000 [21]. However, conducting a comparative study is difficult due to the relatively rare cases of the SBS. In this study, one SBS child had a moderate SNHL. However, this finding should be interpreted with precaution because we did not have previous hearing evaluation to rule out congenital hearing loss. Nevertheless, it should alert concerned health care providers to the possibility of hearing deterioration in children victimized of SBS. Experimental studies have shown small blood vessel damage in prolonged ischemia [22]. Also, congenital hearing loss has been noticed in prolonged and difficult labor and delivery leading probably to an ischemic effect of the small labyrinthine arteries. The main limitations of this study are the small number of children and in some, the long delay between the infliction and the
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audiometric evaluation. In addition, the long-term follow up of those children is not evaluated. Despite that, this is the first study to predict hearing loss in SBS. Inspired of our findings, we believe that all children victimized of this infliction should be evaluated for hearing loss as early as they are stabilized to avoid unintentional neglect and most important for early detection and proper rehabilitation. In addition, the implementation of universal newborn hearing-screening programs before hospital discharge will be helpful as a reference test for children in case of later on infliction. The universal newborn hearing-screening program before hospital discharge was started in our institution 2 years ago. 5. Conclusion This is the first report studying a correlation between hearing loss and shaken baby syndrome. Hearing loss may be a result of SBS. However, further studies with larger number of children would be preferable. However, we recommend a universal newborn hearing screening programs before hospital discharge and a hearing evaluation for all SBS children to rule out hearing loss. References [1] M.A. Mraz, The physical manifestations of shaken baby syndrome, J. Forensic Nurs. 5 (1) (2009) 26–30. [2] A.N. Guthkelch, Infantile subdural haematoma and its relationship to whiplash injuries, Br. Med. J. 2 (May (5759)) (1971) 430–431. [3] W. Squier, Shaken baby syndrome: the quest for evidence, Dev. Med. Child Neurol. 50 (January (1)) (2008) 10–14. [4] J.D. Kivlin, Manifestations of the shaken baby syndrome, Curr. Opin. Ophthalmol. 12 (June (3)) (2001) 158–163. [5] A.V. Levin, Retinal hemorrhage in abusive head trauma, Pediatrics 126 (November (5)) (2010) 961–970. [6] J. Matschke, K. Pu¨schel, M. Glatzel, Ocular pathology in shaken baby syndrome and other forms of infantile non-accidental head injury, Int. J. Legal Med. 123 (May (3)) (2009) 189–197. [7] Y. Morad, T. Wygnansky-Jaffe, A.V. Levin, Retinal haemorrhage in abusive head trauma, Clin. Exp. Ophthalmol. 38 (July (5)) (2010) 514–520. [8] B.M. Togioka, M.A. Arnold, M.A. Bathurst, S.M. Ziegfeld, R. Nabaweesi, P.M. Colombani, et al., Retinal hemorrhages and shaken baby syndrome: an evidence-based review, J. Emerg. Med. 37 (July (1)) (2009) 98–106. [9] K. Tsao, M. Kazlas, J.J. Weiter, Ocular injuries in shaken baby syndrome, Int. Ophthalmol. Clin. 42 (3) (2002) 145–155. [10] T. Wygnanski-Jaffe, Y. Morad, A.V. Levin, Pathology of retinal hemorrhage in abusive head trauma, Forensic Sci. Med. Pathol. 5 (December (4)) (2009) 291–297. [11] W. Squier, The, ‘‘Shaken Baby’’ syndrome: pathology and mechanisms, Acta Neuropathol. (Berl.) 122 (November (5)) (2011) 519–542. [12] L. Altimier, Shaken baby syndrome, J. Perinat. Neonatal Nurs. 22 (January–March (1)) (2008) 68–76 (quiz 77–78). [13] J.F. Geddes, R.C. Tasker, A.K. Hackshaw, C.D. Nickols, G.G.W. Adams, H.L. Whitwell, et al., Dural haemorrhage in non-traumatic infant deaths: does it explain the bleeding in shaken baby syndrome? Neuropathol. Appl. Neurobiol. 29 (February (1)) (2003) 14–22. [14] Y. Morad, Y.M. Kim, D.C. Armstrong, D. Huyer, M. Mian, A.V. Levin, Correlation between retinal abnormalities and intracranial abnormalities in the shaken baby syndrome, Am. J. Ophthalmol. 134 (September (3)) (2002) 354–359. [15] A.C. Lee, K.T. So, D. Fong, S.H. Luk, The shaken baby syndrome: review of 10 cases, Hong Kong Med. J. 5 (December (4)) (1999) 337–341. [16] W.J. King, M. Mackay, A. Sirnick, Canadian Shaken Baby Study Group, Shaken baby syndrome in Canada: clinical characteristics and outcomes of hospital cases, Can. Med. Assoc. J. 168 (January (2)) (2003) 155–159. [17] A.C. Duhaime, C.W. Christian, L.B. Rorke, R.A. Zimmerman, Nonaccidental head injury in infants – the shaken-baby syndrome, N. Engl. J. Med. 338 (June (25)) (1998 Jun 18) 1822–1829. [18] M.T. Prange, B. Coats, A.-C. Duhaime, S.S. Margulies, Anthropomorphic simulations of falls, shakes, and inflicted impacts in infants, J. Neurosurg. 99 (July (1)) (2003) 143–150. [19] C.W. Christian, R. Block, Abusive head trauma in infants and children, Pediatrics 123 (May (5)) (2009) 1409–1411. [20] M.C. Cohen, A. Sprigg, E.H. Whitby, Subdural hemorrhage, intradural hemorrhage and hypoxia in the pediatric and perinatal post mortem: are they related? An observational study combining the use of post mortem pathology and magnetic resonance imaging, Forensic Sci. Int. 200 (July (1–3)) (2010) 100–107. [21] A.K. Biswas, S.C. Goswami, D.K. Baruah, R. Tripathy, The potential risk factors and the identification of hearing loss in infants, Ind. J. Otolaryngol. Head Neck Surg. 64 (September (3)) (2012) 214–217. [22] H. Lu, J. Zhao, M. Li, Y. Cheng, Y. Li, X. You, et al., Microvessel changes after postischemic benign and malignant hyperemia: experimental study in rats, BMC Neurol. 10 (2010) 24.
Please cite this article in press as: M. Alzahrani, et al., Hearing loss in the shaken baby syndrome, Int. J. Pediatr. Otorhinolaryngol. (2014), http://dx.doi.org/10.1016/j.ijporl.2014.02.018
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