This experiment was an extension of the one previously reported. From the viewpoint of the external and internal feedback models for speech control, the following hypotheses were studied. 1) The DAF index of familiar words was less than that of nonsense syllables. 2) The DAF index of repeated practice groups was less than mthat of single practice groups. 3) The DAF index of girls was less than that of boys. The DAF index was used to indicate DAF effects, which was defined by the following formulla: 1- (CMR under DAF/CMR under NAF) . CMR was the correct morae rate of reading per second. The subjects read 6 familiar words and 6 unfamiliar nonsense syllables. 45 boys of the 5th grade with normal speech habit were divided equally into three groups, who practiced 1, 10 and 30 times before the DAF test. 45 girls were similarly chosen and divided. The 2nd and 3rd hypothesis were supported but the 1st was not. Although it was not significant, the DAF index of the familiar words was less than that of nonsense syllables in the 1 and 30 practice groups, but in the 10 practice groups, the result was reversed. Measuring reading difficulties under the DAF, it was also proved that the DAF index represented validity and generality as an index of the DAF effect.
Investigation of clinical sense and the problem of non-verbal intelligence testing was undertaken for 45 cases of hearing and speech handicapped children. All test cases were under the age of 12 and had speech training for more than three years. Non-verbal intelligence testing was effective for evaluating their intelligence and the effects of speech training. 1) (a) None of the 45 cases underwent non-verbal intelligence testing previous to visiting our clinic, and as a result 90% of them had been evaluated as having lower intelligence, while 10% were judged to be mentally deficient. Following non-verbal intelligence tests at our clinic, of 39 cases who had been diagnosed mentally deficient in addition to other lesion, 36 cases showed normal non-verbal intelligence and 3 cases showed border-line intelligence. On the other hand, 6 cases who had been diagnosed as having a hearing loss only or a cleft palate only were shown to be mentally deficient as well. (b) As concerns the cause of impaired speech for the 45 cases, of 36 cases with normal non-verbal intelligence, 21 cases showed perceptive hearing loss, 7 cases were obscurr, 5 cases were epileptic, and 3 cases resulted from other causes. Three cases of border-line non-verbal intelligence showed impaired speech in addition to abnormal behavior whose cause was obscure. Six cases of retarded non-verbal intelligence showed mental deficiency in addition to hearing loss or cleft palate. 2) As a result of our speech training extending over more than three years, of 27 cases (60% of total), 26 cases of normal non-verbal intelligence and 1 case of border-line intelligence were developed, and verbal intelligence reached a level equal to that of non-verbal intelligence. 3) Non-verbal intelligence testing is important as a basic discernment test on speech handicapped children and as a clinical method for evaluating learning, hearing and speech ability. 4) There remain certain problems and limitations as the results of speech training are evaluated by non-verbal intelligence testing only. The role of non-verbal intelligence in the speech learning process must also be defined in relation to speech learning ability. New tests should be designed for this purpose.