The inner ear is an organ which has two functions; the cochlea is
responsible for hearing and the vestibular system for balance. Alterations
in these organs can cause major difficulties for human beings, such as
reduction in the capacity to react to environmental sounds, to keep an
effective communication with the environment or even to maintain body
balance (Schmidt et al., 2010).
The hormonal alterations which happen during pregnancy can
result in changes in the homeostasis of labyrinthine fluids, since they
have a direct influence on the enzymatic process and the action of
neurotransmitters. The compromise of labyrinth fluid characteristics, as
well as the interference on the sensitivity of enzymatic receptors
influences the basal metabolism of the inner ear. These alterations may be
asymptomatic or associated with otologic symptoms (Bittar, 1999).
Symptoms such as tinnitus, dizziness and sudden hearing loss (HL)
are often associated with the action of estrogen and progesterone on the
cochlea, posterior labyrinth and central auditory pathway. Dizziness is
more frequent in the first two trimesters of pregnancy. Nausea is the main
symptom associated with dizziness in pregnant women. When the
gestational trimesters are compared, nausea is more frequent in the first
gestational trimester and it reduces as the pregnancy progresses (Schimdt
et al., 2010).
Introduction and Rationale
Page 2
The most frequent audiological complaint during pregnancy is
tinnitus with proposed theories including hyperdynamic circulation,
increase in perilymphatic fluid pressure and hormonal changes. More
significantly, tinnitus considered as an early sign of preeclampsia (PE)
(Al-Zubiadi, 2012; Haas et al., 2007).
Sudden sensorineural hearing loss (SSNHL) may occur during
pregnancy, but its prevalence is very low. It is suggested that SSNHL is
closely related to the changes in the cardiovascular system, hematological
system, endocrine system, and/or some other systems due to pregnancy.
These changes possibly evoke disorders of cochlear circulation or
cochlear fluid homeostasis leading to SSNHL (Hou and wang, 2011).
Since, both the clinical manifestations caused by vestibular as well
as hearing disorders affect the life routine; family, social and professional
relations. This cause loss of self-confidence, concentration and
performance causing frustration and depression. So this assay aims at
clarifying the importance of evaluation of audio-vestibular findings
during pregnancy and explanation of the causes. |
