Auditory brain stem response abnormalities in severely and profoundly retarded adults

Generation of auditory brain stem responses (ABRs). I. Effects of injection of a local anesthetic (procaine HCl) into the trapezoid body of guinea pigs and cat

“…These same variables can also be used along with scalp distribution in clinical application of ABR testing to aid in the identification of altered ABR components. It is intriguing in this experimental study that a brain stem lesion was accompanied by a shortening of both absolute (P4) and intercomponent latencies (P1-P4) whereas in clinical situations this phenomenon has only been noted with lesions of the cochlea (Coats and Martin 1977) and in children with Trisomy 21 syndrome (Squires et al 1980). Destructive lesions of the central auditory pathway in human have been associated with a prolongation of absolute and intercomponent conduction times (Start 1977;Stockard and Rossiter 1977).…”

Brain auditory evoked potentials in children with Down syndrome

“…It has been proved that hearing loss occurs more often in children with Down syndrome than in the population of healthy children or those with other development disturbances [3,8]. Most authors agree that hearing loss in children with Down syndrome is usually conductive, but there are also reports suggesting mixed or sensory forms of the disturbances [3,[8][9][10][11][12][13][14][15][16]. Many authors showed impaired response in brain auditory evoked potentials (BAEP) in these children, but the findings are often ambiguous or even contradictory [2,11,[16][17][18][19].…”

“…Courchesne et al [28] did not find any disturbances in the BAEP results of 14 autistic patients without mental retardation. Squires et al [16] have tested 31 patients with mental retardation, including 16 subjects with Down syndrome. Interpeak latencies I-V were significantly shorter in 33% of the Down syndrome patients, and significantly longer in only one case.…”

Generation of auditory brain stem responses (ABRs). II. Effects of surgical section of the trapezoid body on the ABR in guinea pigs and cat

“…Only two of these changes, that of prolongation of latency and alteration of amplitude, are routinely used as criteria of abnormality of the ABR in clinical tests (Start and Achor 1975;Stockard and Rossiter 1977;Chiappa et al 1979;Rowe 1981). A shortening of latency has only rarely been considered as a criterion of abnormality and restricted to disorders of the cochlea (Coats and Martin 1977) or to Trisomy 21 (Squires et al 1980). Absolute amplitude changes are u~ by only a few (Thornton and Hawkes 1976;Uziel and Benezech 1978) because of its high variability, whereas the amplitude ratio of component V/I is used more often.…”