Based upon the authors' previous study, in which they concluded that the articulation score obtained at the level of “most comfortable loudness for speech hearing” roughly coincides with the score of maximum articulation, the authors designed a simplified speech hearing test as a routine work which is named “MCL speech test”. This test is conducted in a following way; (1) Most comfortable loudness level for speech hearing is determined at first with a connected discourse which is recorded in a channel of a stereophonic recording tape. (2) Articulation score is then determined with 20 monosyllabic and meaningless test words which are recorded in another channel of the same tape with the same intensity as the connected discourse. (3) Since the recording tape used in this test is a stereophonic, the examiner is required only to change the test channel from the connected discoures to the test words after the MCL is determined. (4) It is possible to examine not only the articulation score but also hearing ability for distorted speech, switched speech, binaural fusion, binaural separation and so on at the level of MCL.
In this study, the results of the articulation score of the voiced and voiceless consonants were compared in volunteers and patients. Using the Japanese test materials List 57 AB and List 67 AB, we selected the pre-vowel voiced consonants group and the pre-vowel voiceless consonants group from their monosyllable words. For discrimination measuring, the intensity was kept constant every one list and presented at each 10dB in random order of sensation level, and the percentage of correctly repeated words was recorded for both the voiced and voiceless consonants group. In normal subjects the discrimination ability for the voiced consonants was many times somewhat better than for the voiceless consonants. In conductive deafness this relationship was the same as in normal ears. In perceptive high tone deafness, the voiceless consonants were more poorly discriminated than the voiced consonants. In mixed deafness the situation was not so clear. On the other hand, the curve with rising or horizontal air conduction thresholds in Ménièr's disease was associated with a clearly lower discrimination for the voiced consonants than for the voiceless consonants. This phenomenon might be applicable in typical cases of perceptive deafness in speech range with complete recruitment.
The problem investigated was to determine if a program of educational audiology would aid the speech and language development of the moderately to severely hard of hearing child to the extent that the child, when he enters school, might be integrated into a normal hearing classroom. The study had as its primary aim an evaluation of such a program (sometimes referred to as the “acoupedic method”) as a method for training the deaf and hard of hearing child primarily through the auditory sense. The approach under investigation developed in recent years out of the emphasis on early diagnosis and its subsequent stress upon early remedial programs for handicapped children. It differs from most modern approaches, however, in that it is basically uni-sensory, stressing audition, rather than multi-sensory, wherein audition and vision are utilized simultaneously. The theoretical premises underlying the program are: 1. The auditory sense is the most suitable perceptual modality by which a child learns speech and language. 2. The multi-sensory approach to management favors the development of the unimpaired modality as the primary communication system at the expense of the impaired modality whereas the uni-sensory approach stresses development of the impaired modality to its fullest potential. 3. The devlopment of sound awareness, vocal production, and, eventually, the beginnings of speech and language can best be achieved in the child's home so long as suitable acoustic stimulation is provided. 4. Presnet day nursery school procedures patterned after those developed for totally hearing children are preferable to those designed around “special education”. From a total of 33 children enrolled in an experimental uni-sensory program at the University of Denver, 12 whose total remedial management has been in the program described and who had achieved the fifth birthday by the conclusion of the study were selected for detailed analysis of audiometric, case history, parental environment, and speech and language data. A similar group, whose early management had been multi-sensory, of 16 children obtained through the cooperation of the Cleveland Hearing and Speech Center provided comparative data on hearing loss, speech and language development. While no strict matching was possible between individual members of each group, comparisons of data obtained by the fifth birthday were made and analyzed. On all measures of speech and language acquisition, the Denver group was markably superior to the Cleveland group although the superiority was less evidenced on the Templin-Darley Articulation Test. On all other measures (mean length of response, mean of 5 longest responses, number of 1-word responses, number of different words structure compleqity score) the Denver group would appear to indicate the advisability of uni-sensory as opposed to multi-sensory management. Such generalizations, however, are not made on the basis of other variable such as familiarity with the test situation, continual enrollment in the original clinical program, etc. On the basis of the findings, however, certain recommendations are made regarding the utilization of uni-sensory management; for children whose residual hearing extends into the high frequencies and whose hearing losses are relatively flat the approach seem most appropriate. Other children, assuming relatively normal intelligence and cooperative home environments, might be enrolled in such a program for diagnostic purposes but if marked gains in speech and language acquisition are not seen following a suitable trial period of amplification and education on of the more traditional approaches might prove to obtain better results.