EVALUATION OF SUSCEPTIBILITY OF TTS IN MALES AND FEMALES IN
RELATION TO LEFT-RIGHT EAR ASYMMETRY
Jennifer Suzanne Puckett, M.S
T. Newell Decker, Ph.D.
Tom Carrell, Ph.D.
University of Nebraska-Lincoln
Lincoln, NE 68586-0731
INTRODUCTION
After exposure to certain levels of noise, changes in hearing threshold can be
permanently or temporarily observed. Both permanent and temporary hearing threshold
changes have been shown to have an asymmetric affect on the right and left ears. Also,
temporary reversible changes in threshold have been found to affect men and women
differently.
Left-Right Asymmetry
Interaural hearing asymmetry has been analyzed in many studies of various
populations with the conclusion that the right ear has slightly greater acuity than the left
ear. Ward (1957), compared the median differences (left minus right) with two Wisconsin
State Fair surveys and found median differences on the order of 2.4-3.4 dB between the
two populations.
According to Glorig (1958) the average inferiority of the left ear of males from a
normal population is on the order of 2.8 dB at 4 kHz. The left ears of women were
inferior to right at an average of 0.4 dB. Kannan and Lipscomb (1974) compared right
and left ear hearing thresholds at frequencies of 2-6 kHz in five studies of a normal
population. They concluded that the left ear had statistically significantly higher
thresholds than the right at all frequencies tested in males. Females showed no
significant difference in hearing thresholds between the ears. Rudin, Rosenhall, and
Svardsudd (1988) studied the between ear difference of 987 males age 50 to 60 years. At
high frequencies, the left ear was poorer by an average of 3 dB.
Axelsson and Lindgren (1981) compared hearing thresholds between ears in 139
classical musicians exposed to occupational noise. They found that 88 musicians showed
an asymmetry between ears greater than 15 dB at one frequency. They also found left ear
to be worse in 52 of the 88 musicians, on the order of 3-5 dB poorer among the males an