‘ tee bn dn nian i tans DR teil tote alin ee ee eet a a ca ie ll ant,el Minel deli. acl Atle sat ler +4 1 min and measuring the timefor the skin fold to retract to the surrounding skin surface. The exact end point was sometimesdifficult to measure in older people, and if the fold had not retracted completelyin 90 sec, this time measurement was _used at the maximum. (3) Graying of the Hatr. The degree of graying was expressed on a 0 to 4+ scale as follows: 0, no graying; 1+, slight “salt and pepper” graying; 2+, moderate “‘salt and pepper” graying; 3+, nearly complete graying; 4+, complete graying. Special Senses.* (1) Eyes. All ophthalmologi- cal values were obtained during the 1964 survey. (a) Accommodation was measured in diopters by use of the Prince refracting rule. The average reading of the two eyes was used. (b) Visual acuzty was measured by Snellen’s test. It was found that by taking the square root of the average visual acuity (denominator) of the two eyes the scale was more linear. Thus the best vision, 20/10, was repre- sented as 3.2 (the square root of 10), the worst reading, 20/200, was represented as 14.1 (the square root of 200), and intermediate readings were similarly recorded. (c) Arcus senilis wasestimated on a 0 to 4+ scale. Only slight limbic clouding was considered as | + with increasing clouding as 2+ or 3+ and marked clouding as 44, (2) Ears (Hearing). Audiometric examinations were carried out in a special cubicle lined with acoustic tile. A rugged screening type of audiometer was used.** Impairment of hearing was averagedfor the two earsas follows: the decibel loss for Figure 33. Marshallese subject taking light-extinguishing test of neuromuscular and mentalability as part of the aging study. each of the 6 frequencies (200, 500, 1000, 2000, 4000, 7000) for each ear was averaged, and a adjusted level of physical activity such as resting for a standard period oftime prior to the readings. Pressures were taken from the left arm with the subject supine during the course of the physical “With regard to the reliability of determinations using the at 20 V. The end point wasthe voltageintensity required for perception of the vibration. (2) Neuromuscular Function. This was measured by having the mean frequencyloss in decibels for the two ears was obtained. Cardiovascular Changes. Systolic Blood Pressure. Two readings were obtained with the standard aeronoid cuff-type sphygmomanometer, and the averageof the two was used. There was nobasic or Prince refracting rule, Snellen’s test, and hearing acuity, it should be pointed out that these tests were carried out under standardized conditions; but, in view of the necessity of using an interpreter under field conditions, it was not feasible to have the test repeated by more than one examiner. The data from these tests are believed to be sufficiently reproducible to be ofrelative value. although not so accurate perhaps as might be obtained examination. Neurological and Neuromuscular Function. (1) Vibratory Sense. Vibratory perception was measured over the head of the left tibia by an electric vibrometer set at a standard frequencyof 120/sec subject depress the key of a hand-tally type of blood cell counter as many times as possible in the period of one minute (1964 data), The total number of depressions represented the score. (3) Light Extinction Time.* A battery of lights were connected under more desirable conditions. in random series, and the subject extinguished curement Agency, Fort Totten, New York, for loan of the audiometer. for information on the construction and use of this instrument. ** The authors are grateful to the Armed Services Medical Pro- 90086328 *We are grateful to Dr. J.W. Hollingsworth of Yale University