THE ASSOCIATION OF AUDITORY HIGH FREQUENCY WEAKNESS WITH VERBAL AND WRITTEN COMPREHENSION AND EXPRESSION

Abstract

Clinical observation prompted the hypothesis that failure of response to high frequency tones outside the speech range is associated with linguistic impairment. Pure tone audiometric assessment of school children was carried out, special equipment being used to ascertain normal upper limits of hearing. In a representative sample of 209 children the mean upper limits in the age groups 7 to 12 were about 18,000 cycles per second, but a significant lowering of limit with age was then apparent, the mean at age 15 being just above 16,000 c.p.s Further surveys of maladjusted children, retarded readers and educationally subnormal children demonstrated that high frequency auditory acuity is positively associated with intelligence and with introversion. From 484 children tested 20 cases of relative high frequency weakness (HFW) were selected. The group included 9 boys and 11 girls aged 8 to 13, with a ride range of intelligence. These children were individually tested with a battery of eight measures of linguistic development. They proved to be grossly retarded in inferior to 20 matched controls. The most significant group difference were in speech articulation, vocabulary and oral language development. Paucity of ideas, looseness of expression, limited verbal comprehension and general linguistic retardation were also reflected in written composition and tests of sentence structure and reading comprehension. Only in mechanical word recognition was the HFW group's inferiority not statistically significant. The school histories of these HFW children were characterised by retardation or impatient in speech, language, academic attainment and behaviour. It is suggested that HFW is not merely a sensory impairment and may more profitably be regarded as an intervening variable. Attention is drawn to psychological aspects of pure tone audiometry, and discussion is in terms of Vigilance, set, response consistency and extravagation. In addition to their theoretical implications the findings would appear to be of immediate clinical and educational significance