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Neurological and Neuromuscular Function,
({1) Vibratory Sense.
Vibratory perception was measured over the head of the left tibia by an
electric vibrometer, the instrument set at a standard frequency of 120/sec
at 20 volts. The endpoint was the voltage intensity required for perception
of the vibration.
(2) Neuromuscular Function.
Measured by having the
subject depress the key of a hand talley type of blood cell counter as many
times as possible in the period of one minute. The total number of
depressions represented the score. (3) Light Extinction Time, A battery
In order to place all of the data from each criteria on a common basis
for comparison and combination, the data were converted to a percentage
basis for each criteria, In the case of the measured data, values associated
with least ageing were chosen as zero percent (sometimes the highest reading,
as with hand strength; sometimes the lowest, as with hearing loss), and
conversely the values showing most ageing were chosen as 100% The estimated criteria with values of 0, 1+, 2+, 3+ and 4+ were presented as 0, 25,
50, 75 and 100% respectively. The data were examined on an individual
basis as well as on a2 population basis, comparisons were made largely by
using means for each decade age group.
An analysis of variance was used to determine differences among
the factors of sex, age, and radiation levels. These data were programmed
and analysed on a high speed digital computer (The Control Data Corporation
6600 at Brookhaven National Laboratory), For each criterion, the combined
score over sex and radiation level was correlated with age. A curve of
a ee
Miscellaneous Tests.
(1) Body Potassium Levels (49x), Since
loss of muscle mass occurs with ageing and total-body potassium is closely
related to muscle mass, it has been shown that body levels of potassium
decrease with age (Anderson and Langham 1959; Allen, Anderson and
Langham 1960), Whole-body spectrographic analyses were carried out in
the Marshallese using a lead-shielded structure, In this way 40K levels were
obtained and presented as K/kg body weight. Accuracy of these data could
have been improved by obtaining more precise determinations of lean body
mass, such as by measurement of body water (Allen, Anderson and Langham
1960). (2) Blood Serum Cholesterol Levels.
These were obtained on sera
which had been returned from the Islands.
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light as it appeared, The total time necessary to extinguish all of the lights
was measured. This test involved both manual dexterity and mental reaction
time (Hollingsworth, Hashizume and Jablon 1965), (4) Hand Strength.
Measured by a Smedly hand dynamometer (S,H. Stoelting Co., Chicago,
Tlinois. ) The spring tension of the hand grip was measured in kilograms.
The maximum squeeze strength in the dominant hand in three tries was
recorded,
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of lights were connected in random series and the subject extinguished each