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D A Shannon

Publications and source records attributed to D A Shannon.

3 recordsLinked to original sources

Hearing screening of high-risk newborns with brainstem auditory evoked potentials: a follow-up study.

Numerous techniques have been used in attempts to find a reliable and efficient screening method for determining auditory function in the newborn. The brainstem auditory evoked potential (BAEP) is the latest method advocated for that purpose. The BAEP was evaluated as a hearing screening test in 168 high-risk newborns between 35 and 45 weeks of conceptual age. Follow-up data were obtained after 1 year (mean 17.3 months) on 134 of the infants (80%). Normal hearing was defined as a reproducible response in both ears to a 25 dB normal hearing level (nHL) click stimulus; 21 infants (12.5%) failed the initial screening test. Follow-up on 19/21 infants revealed 18 infants with normal hearing and one infant with an 80 dB nHL bilateral hearing loss substantiated. One infant with an abnormal screening test died before retesting, and the other infant was lost to follow-up but had only a unilaterally abnormal BAEP. None of the infants with a normal BAEP screening study had evidence of hearing loss on retesting. Sensitivity of the BAEP was 100%, specificity was 86%, predictive value of a positive test was 5.26%, and the predictive value of a negative test was 100%. The incidence of significant hearing loss in our population was between 0.75% (1/134 infants) confirmed, and 2.24% (3/134 infants) including infants who failed screening but were lost to follow-up. The BAEP is a sensitive procedure for the early identification of hearing-impaired newborns. However, the yield of significant hearing abnormalities was less than predicted in other studies using BAEP for newborn hearing screening.

Brain Stem↗

Surgical treatment of long-term sensorineural hearing loss due to labyrinthine fistula.

Perilymphatic fistula, usually in the round or oval window, causes a variety of symptoms, including sensorineural hearing loss. Surgical repair of these fistulas has resulted in restoration of hearing in some cases. It has been suggested that surgery must be performed within 2 months of the trauma if improvement in hearing is to occur. This paper presents the case of a patient whose fistula and resulting hearing loss had persisted ten years before surgical repair. Restoration of normal hearing and discrimination of speech occurred in the ear which had previously presented a severe sensorineural hearing loss with no useful discrimination for speech. The authors usge audiologists and otolaryngologists to consider the possibility of fistula in cases of sudden hearing loss, even when years have elapsed since the trauma. Their experience suggests that surgery may be successful in restoring hearing after many years.

Adult↗

Morse-code-controlled computer aid for the nonvocal quadriplegic.

A computer-based communications system was established for a quadriplegic patient who suffered a brainstem infarction that left him with normal intelligence, but without speech and without functional motor control except for the thumb of his right hand. An arm brace was developed to support the hand and thumb so it could control two switches that generated Morse code signals. An interface was also devised to translate Morse code into ASCII characters to access a personal computer. Additional codes were added to represent keyboard control functions. This device allows the patient to communicate with others and control, to some extent, his environment.

Brain Stem↗