The authors have already discussed low back pain among workers in small scale construction companies in Report 1, in which we demonstrated the high prevalence of low back pain among the workers.
The clinical and radiological examination did not always correlate with clinical findings.
We concluded, therefore, that radiological examination is not so helpful in mass screening for low back pain.
In order to develop more accurate screening procedures, various kinds of clinical findings were discussed.
The results are as follows.
1) The workers with frequent complaints of low back pain have a higher incidence of other musculo-skeletal symptoms than those who experience occasional or no low back pain.
Duration of continuing low back pain among the former is longer than among those in the latter group.
2) A close relationship between the severity of low back pain and the following clinical findings exists.
a) point tenderness of the paravertebral muscles b) pain produced upon flexion, extension or abduction of the trunk c) limitation of flexion-extension of the trunk d) punch tenderness of the vertebral e) disappearance of lordosis f) hypesthesia of the lower extremities
3) Bilateral pateller and / or Ackilles tendon reflexes were different in workers with low back pain.
4) Weakness on extension and flexion of the big toe was often found among the workers with severe low back pain.
5) The authors demonstrated that low back pain is related to strengh of back muscles.
The findings described above indicate that the workers have many difficulties complying with the new recommendations for preventing low back pain.

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Workers, everyone of them aged 55, were tested by the Uchida-Kreapelin (U-K) Test and by the Cybernetical Controllability Number (C. C. No.) Test with respect to their working ability.
We investigated actual conditions and checked the validity of the tests using workers' job grades and personal history of industrial accidents as criteria.
1) Thirty-six per cent belonged to the Non-standard Type on the U-K Test, while 38% was within 1. 0 on the C. C. No. Test. Their level of mental function was rather low. Those found to be of the standard type on the U-K Test were of prompt type on the C. C. No. Test.
2) C class workers on the U-K Test capable of rather small amount of work belonged to low grades.
3) Workers of the hasty type on the C. C. No. Test workers' were low in job grades and few workers were found to be assistant foremen. A few workers were at the top of job grades between 1. 0 and 2. 0 on the C. C. No. Test. Besides, most workers of the hasty type who were within 1. 0 on the C. C. No. had gone through industrial accidents.
4) The group of higher level on the U-K and C. C. No. Tests had less frequent industrial accidents than lower level workers.

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Up to the present social evaluation of the degree of hearing loss is made by the average threshold values for several, pure tones involved in the acoustic range related to speech. This average indicates numerically only a qualitative aspect of the communication capacity. The language used in our daily life is formed by tones of various frequencies and intensities. Accordingly, the degree of actual competence of communication can not simply. be indicated by such average values. Threshold is the sound-level which is just noticeable. Therefore, the scale related to easiness for hearing should be included into the social evaluation on the degree of hearing loss.
From the above-mentioned view point, this study was made for clarifying the relationship between the auditory threshold and the most comfortable loudness level (MCL) elicitable by pure-tone and speech audiometry. And more over a classification on 20 monosyllables was made by using the “hard-easy” scale for listening. The subjects were 124 male workers (248 ears) engaged in noisy work-shops. Noise levels in these work-shops were 90 dB (A) or over.
The following results were obtained :
(1) High positive correlations were found between the threshold at 4000 Hz and those at 3000 and 6000 Hz, and between the threshold at 1000 Hz and those at 500 and 2000 Hz. From these facts, 1000 Hz and 4000 Hz were useful test-frequencies for early detection of noise-induced hearing loss.
(2) High positive correlation between the threshold and MCL was found in at each frequency, especially in high frequencies.
(3) Inverse correlation was found as significant between the threshold and MCL-threshold. That is, a recruitment phenomenon was observed in workers with noise-induced hearing loss.
(4) The auditory threshold at which MCL begins to increase significantly above the normal MCL level was 30 dB at 4000 Hz and 0 dB at the average frequency value (C₂+2C₃+C₄) /4 or (C₂+2C₃+2C₄+C₅) /6.
The auditory threshold at which the impairment of communication in daily life begins was 50 dB at 4000 Hz, 0 dB at the average value (C₂+2C₃+C₄) /4, and 20 dB at the average value (C₂+ 2C₃+2C₄+C₅) /6.
(5) Monosyllables listened easily were “A”, “Wa”, “To” and “O”, while those hard of listening were “Ji”, “Ki”, “Ne”, “Su”, “Shi”, “Te” and “Ri”.
(6) Monosyllables with which the subjects frequently tended to confused were as follows : “Ha”, “Ta”, “Mo”, “Ba”, “Ga”, “Te” and “Ne”. The confusion was mainly related to the consonant coming at the top of the word.
(7) In the examination of articulation of the monosyllables at the minimum intelligible level, “Ni”, “Shi”, “Ga”, “Ki” and “Su” showed higher rates in subjects with normal auditory threshold than in those with hearing loss.
(8) In the examination of articulation of the monosyllables at MCL (for sentence), “Ki”, “Su”, “Te” and “Ji” showed higher rate in subjects with normal auditory threshold than in those with hearing loss.
(9) In the examination of MCL for monosyllables, those monosyllables which showed the same pattern mentioned above were “Ni”, “Su” and “Ji”, but “Ri” showed significantly lower articulation rate in subjects with hearing loss.

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