عنوان مقاله
اتیولوژی و توصیف اختلالات پردازش شنیداری به روش بالینی
فهرست مطالب
مقدمه
آناتومی سیستم عصبی شنیداری مرکزی
نمایش بالینی
طبقه بندی
مدیریت
نتیجه گیری
بخشی از مقاله
تومورهای CANS : مفهوم APD (مرکزی) به یافته های شنودسنجی Bocca در بزرگسالان مبتلا به تومورهای مغزی بازمی گردد که بر مناطق شنیداری اثر می گذارند. کودکان مبتلا به تومور CANS دارای نقایص گوش مشابه با بزرگسالان هستند، بدون اینکه به ظرفیت انعطاف پذیری مغز توجه شود.
زودرسی و وزن پائین در هنگام تولد: نوزادان زودرس با وزن کم در هنگام تولد از APD رنج می برند که با گذشت زمان به طور چشمگیری افزایش می یابد. اما، تا سن 14 سالگی دربعضی از کودکان نشانه های اختلالات ضعیف شنیداری نظیر گستردگی حافظه شنیداری ضعیف، به میزان بسیار بیشتری نسبت به جمعیتی با وزن تولد نرمال ادامه می یابد.
کلمات کلیدی:
Aetiology and clinical presentations of auditory processing disorders—a review Abstract Auditory processing disorders may have detrimental consequences on a child’s life, if undiagnosed and untreated. We review causes of auditory processing disorders in order to raise clinical awareness. Auditory processing disorders may present against a background of neurological disease or developmental disorders, as well as in isolation. Clinicians need to be aware of potential causes and implications of auditory processing disorders. Keywords: auditory processing; attention deficit , disorder; dyslexia; dysphasia Hearing is a complex process that orchestrates transduction of the acoustic stimulus into neural impulses by the ears, transmission of the neural impulses by the auditory nerves to the brain, and perceptual registration and cognitive elaboration of the acoustic signal by the brain as well as conscious perception of the sound. Hearing impairment(s) arising from pathology of the brain may have detrimental consequences on a child’s life if untreated; however, diagnostic and management strategies for these “central” hearing impairments in childhood are rarely implemented. These auditory deficits have been collectively termed “auditory processing disorders”, in order to incorporate in the term the interaction between peripheral and central pathways.1 A rough prevalence estimate for auditory processing disorders (APD) in childhood is 7%.2 Despite the frequency of the problem, a systematic approach to the diagnosis and rehabilitation of APD in children has only started emerging over the past 30 years, as a result of developments in basic sciences; emphasis has shifted from identification of the lesion that causes the disorder to identification of the impaired individual’s difficulties and their appropriate remediation.3 Anatomy of the central auditory nervous system The central auditory nervous system (CANS) extends from the cochlear nucleus in the brain stem to the auditory cortex. The superior olivary complex, lateral lemniscus and inferior colliculus, medial geniculate body, and reticular formation are important relay stations. The ortical and subcortical auditory areas mainly consist of Heschl’s gyrus, the planum temporal (extending from the posterior aspect of Heschl’s gyrus to the end of the Sylvian fissure), and the Sylvian fissure with the insula.4 The cerebral hemispheres are connected by the corpus callosum. The CANS is characterised by an intrinsic “redundancy”—that is, an extensive interaction of its structures that is responsible for the resistance of the system to exhibit deficits on standard auditory testing in the presence of a lesion.4 In children, myelination and maturation continue until 10–12 years of age.5 The young brain has an inherent ability for plasticity: the forebrain sensory representations may change in response to altered receptors, sensory environment, or use and learning.6 Clinical presentation Children with auditory processing disorders appear to be uncertain about what they hear, and may have difficulties listening in background noise, following oral instructions, and understanding rapid or degraded speech in the presence of normal peripheral hearing.1 Symptoms may become apparent in the early school years or at a later academic stage of the child’s life, due to changes in the acoustic environment or to increased academic demands. In rare cases, these symptoms may be the first manifestation of a neurological disorder.7 As a consequence of the primary auditory difficulties, children with APDs may have secondary characteristics of language, reading and spelling disorders, as well as inattention and distractibility (table 1)2; this profile requires careful consideration and diagnostic evaluation for differentiation from other common childhood developmental disorders. Auditory processing disorders may result from disruption of processes specific to audition, as well as from more global deficits (for example, memory or attention deficits) that have a negative impact on the processing of auditory information.8 Irrespective of the causal mechanism, an APD may manifest as a deficit in sound localisation, discrimination, pattern recognition, temporal processing, and performance deficits
