International Journal of Otolaryngology and Head & Neck Surgery, 2013, 2, 201-206 Published Online September 2013 (
Audiological Evaluation in Goitrous Hypotyhroidism
M. K. Aggarwal1, Gautam Bir Singh2*, Ranjan K. Nag1,
S. K. Singh1, Rajesh Kumar1, Mayank Yadav2
1Institute of Medical Sciences, BHU, Varanasi, India
2Lady Hardinge Medical College & Associated Hospitals, New Delhi, India
Received May 26, 2013; revised June 25, 2013; accepted July 10, 2013
Copyright © 2013 M. K. Aggarwal et al. This is an open access article distributed under the Creative Commons Attribution License,
which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
Obje ctive: To determine the incidence of deafness in patients suffering from goiterous hypothyroidism exclusively and
to evaluate the role of L-thyroxine therapy in improving the hearing in this group of patients. Study Design: A prospec-
tive cohort study. Materials and Methods: Hearing status was evaluated in a sample size of 100 consecutive patients
reporting to the ENT/Endocrinology department of Institute of Medical Sciences, Banaras Hindu University, Varanasi,
UP with the diagnosis of goitrous hypothyroidism. The study group included patients in the age group of 5 to 65 years
belonging to either sex. Patients with detected hearing loss were categorized into group A, and all other patients were
designated group B. L-Thyroxine treatment for goitrous hypothyroidism was initiated in all the cases. At the end of 6
months, a repeat audiogram was done in all the patients in order to evaluate the efficacy of the said treatment protocol on
the hearing in these patients. The data were tabulated and statistically analysed using Paired Students “t” test. Results:
An overall 39% hearing loss was observed in patients with goitrous hypothyroidism. 15% cases had sensorineural hear-
ing loss, 13% had mixed hearing loss and 8% had a conductive hearing loss. A statistically significant hearing improve-
ment was recorded in this study by L-thyroxine treatment in group-A, and no deterioration of hearing was recorded in
group-B. Conclusions: The incidence of sensorineural hearing is less in patients with goitrous hypothyroidism (15%) as
compared with the overall incidence of sensorineural hearing loss reported for hypothyroidism (30% - 40%). Further,
there is a definitive improvement in hearing with the use of L-thyroxine treatment of goitrous hypothyroidism.
Keywords: Hypothyroidism; Goitre; Hearing Loss; L-Thyroxine Treatment
1. Introduction
Hearing loss was first reported in acquired hypothyroid-
ism in 1907 [1]. Over a period of time, a distinct associa-
tion between hypothyroidism and auditory system dys-
function has been reported in medical text [2], though
there are studies which have failed to elucidate a defini-
tive relationship between hypothyroidism and deafness
[3-5]. The medical literature now mentions vertigo, hear-
ing loss, tinnitus and pruritic external auditory canal as
important vestibular and audiological symptoms of hy-
vpothyroidism [2].
Hypothyroidism is associated with all types of deaf-
ness: sensorineural, mixed and conductive, however, the
real incidence and pathophysiology of this hearing loss in
these patients is still uncertain. This is attributed to the
marked paucity of literature on the cited subject. The in-
cidence of hearing loss varies from 25% to 50% with a
higher incidence in congenital hypothyroidism [6,7].
Moreover, the results of audiological evaluation of pa-
tients with hypothyroidism under treatment with L-Thy-
roxine [LT] are conflicting. There are studies which have
highlighted the importance of this modality of treatment
in improving hearing in hypothyroid patients [8-12], but
literature is also replete with studies which have found no
correlation between the two [3-5,13,14]. Considering this,
in order to broaden the studies in this line of research a
prospective study was initiated exclusively in goitrous
hypothyroid patients with the aim to:
1) Determine the incidence of hearing loss in these pa-
2) Evaluate the effect of LT therapy on this hearing
loss in these patients.
To our knowledge, the current study is unique, in that
audiological evaluation of goitrous hypothyroidism has
not been previously reported in medical literature.
*Corresponding author.
opyright © 2013 SciRes. IJOHNS
2. Materials & Methods
A prospective outcome analysis study was carried out in
the departments of Otorhinolaryngology & Endocrinol-
ogy, Institute of Medical Sciences, Banaras Hindu Uni-
versity, Varanasi, UP, India from September 2002 to
September 2005. For the purpose of this study 100 con-
secutive patients of either sex suffering from goitre with
hypothyroidism were recruited in the study design. The
study was approved by the University Board of Studies
& Ethics committee, and an informed consent was man-
datory for recruitment in the study design. Paediatric pa-
tients were also recruited in the study design.
All the patients of goitre reporting either to the otorhi-
nolaryngology department or endocrinology department
were subjected to detailed history taking and clinical ex-
amination. A FNAC (fine needle aspiration cytology),
USG (ultrasound) of the enlarged thyroid and screening
for thyroid function was done in all the cases to confirm
the nature of the goitre and the hypothyroidism. The pa-
tients were specifically screened for thyroid dysfunction
by T4 and TSH levels. Thyroid function test were done
by RIA [Radio Immune Assay], the kit for which was
supplied by Bhabha Atomic Research Centre, Mumbai,
India. Only patients with proven hypothyroid status were
enrolled in the study:
Serum thyroxine level (T4): normal range 4 to 13 mi-
Serum thyrotropin (TSH): normal range 0.3 to 6 mi-
cro IU/ml.
Their particulars, detailed history of thyroid swelling
and disease along with clinical examination were entered
in a Performa. Tests to diagnose aetiology of hypothy-
roidism and goitre were also done. A special note of
deafness, vertigo, and tinnitus was also made. The pa-
tients of deafness were further evaluated by tuning fork
test and pure tone audiogram [PTA]. Alps advanced di-
agnostic audiometer AD100 with the following standards
was used for PTA testing:
Tone audiometer: EN60645-1/ANSI S3.6, Type 2;
Speech audiometer: EN60645-2/ANSI S3.6, Type B
or B-E.
It would be prudent to note that hypothyroid patients
with deafness due to any other causes like:
Chronic suppurative otitis media;
Head Injury;
Presbyacusis (patients above 60 years were not re-
cruited in this study);
Ototoxic drugs etc were excluded from the study de-
Finally, these patients with audiogram proven deafness
were categorized in a designated special group-A, all
other patients were enrolled in group-B. Patients in both
the groups continued to receive thyroxine treatment un-
der the supervision of endocrinology department and a
regular monthly follow-up was maintained. At the end of
6 months a repeat audiogram was done and the hearing
status was once again evaluated. A 10 db improvement in
two consecutive frequencies was regarded as an audi-
ological improvement [15,16]. The data was tabulated
and statistically analysed by paired students “t” test.
In this study patient with Hashimoto’s thyroiditis, io-
dine deficiency, thyroid malignancy, irradiated thyroid
malignancy, Pendred’s Syndrome and hyperthyroid pa-
tients treated with drugs/radioiodine etc were all included
in the study design. Distinguishing congenital hearing
loss due to “Pendred’s Syndrome” and other causes of
congenital hearing loss was difficult as “Perchlorate Test”
was not available in our institution. Thus all the cases of
congenital hearing loss with hypothyroidism and goitre
were clinically regarded as “Pendred Syndrome”. Al-
though we recruited cases with diagnosis of hypothy-
roidism with goitre which reported for the first time to
ENT/endocrinology department OPD of our institution,
however during the course of study it was revealed that
some of these patients had taken replacement in the past
for short duration. This was probably due to the rural
background, poor socio-economic status and illiteracy of
our patient profile.
3. Results
Out of a total of 100 patients with goitre and hypothy-
roidism, 70 were females and 30 were males. The age
group of patients ranged from 5 years to 64 years. There
were 12 paediatric patients. The age distribution of these
patients is given in Table 1.
A total of 39 patients had an audiological proven deaf-
ness. However over a period of time 3 patients were lost
in follow-up, thus for statistical interpretation and dis-
cussion in this study the results in 36 patients were taken
into consideration. Out of these 36 patients 8 patients had
conductive hearing loss, 15 patients had sensorineural
hearing loss and 13 patients had a mixed hearing loss.
The distribution of these cases in accordance with WHO
classification is shown in Table 2. The relationship of
this hearing loss with the levels of T4 is also given in
Table 2. The mean T4 levels which were associated with
normal hearing are 2.7 micrograms. From the table it is
clearly evident that the severity of the hearing loss is
directly proportional to the decreasing value of T4 levels.
The hearing thresholds were again measured 6 months
later in euthyroid state post thyroxine therapy. The Table
3 shows the audiological gains after L-thyroxine therapy
in each ear separately and the overall gain in all the 36
patients. The analysis of the data revealed:
1) The 10 db hearing improvement or more is seen in 9
Copyright © 2013 SciRes. IJOHNS
Table 1. Age distribution.
No of
Pt’s 5 - 14 15 - 24 25 - 34 35 - 44 45 - 54 55 - 60Total
Group-A 3 7 10 12 6 1 39
Group-B 9 23 9 12 5 3 61
Total 12 30 19 24 11 4 100
*No of Pt’s: Number of patients; *Group-A: Goitrous hypothyroid patients
with hearing loss; *Group-B: Goitrous hypothyroid patients with normal
Table 2. Hearing loss (with correlation to mean T4 levels).
Hearing Loss Number of Cases
Mean T4
Normal 61 2.7
Mild (25 - 40 db) 11 2.6
Moderate (41 - 55 db) 10 2.4
Moderately severe
(56 - 70 db) 14 2.3
Severe (71 - 90 db) 04 1.8
Profound (>90 db) nil N/A
Table 3. Overall response to l-thyroxine treatment.
[db] 7 6 5 4 3 2 1 0 1 23 4 5 6 7 8 9101112
No of
Ears 1 0 0 0 2 1 0 4 0 109 0 16 0 13 7 0702
No of
Pts 1 0 0 0 0 0 0 0 0 4 7 0 8 0 5 6 0401
*Imp (db): improvement in Pure tone audiometry [average] in decibels; *No
of ears: total number of ears i.e. 36 × 2 = 72; *No of pts: total number of
patients in study design = 36.
ears only;
2) The 10 db hearing improvement or more in totality
is seen only in 5 patients;
3) A decrease in hearing was recorded in 4 ears across
various frequencies;
4) One case recorded a significant decrease in hearing
by 7 db;
5) A hearing improvement was recorded in 64 ears,
ranging from 2 db to 12 db;
6) A hearing improvement was recorded in 35 of the
36 patients.
The Table 4 highlights the improvement in hearing
following thyroxine treatment in each specific frequency
i.e. 500 Hz, 1000 Hz, 2000 Hz and 4000 Hz. The study
of the data indicates that:
1) A gain of 10db or more was recorded in 24, 31, 22,
and 25 ears at 500 Hz, 1000 Hz, 2000 Hz and 4000 Hz
Table 4. Response to l-thyroxine treatment (frequency spe-
cific/each ear).
Improvement in hearing (db) (36 × 2 = 72 ears)
(Hz) 10 5 0 5 10 15 Total
500 2 13 13 20 13 11 72
1000 0 08 16 17 16 15 72
2000 0 10 20 20 14 08 72
4000 0 07 18 22 14 11 72
2) Maximum significant gain of 10 db or more was
seen at 1000 Hz (31 ears);
3) A decrease in hearing threshold varying from 1 to
10 db was seen maximally at 500 Hz (15 ears). Other
frequencies showed a miniscule upto 5 db decrease in
hearing only.
The overall audiological improvement after thyroxine
treatment was statistically analysed using paired students
t” test by comparing the average hearing threshold by
pure tone audiometry for each patient at 500, 1000, 2000,
3000, 4000 Hz before and after thyroxine therapy (Table
5). In this study the value of “P” was found to be highly
significant (Table 5). Thus, indicating that thyroxine the-
rapy benefits hearing in goitrous hypothyroid patients. In
addition, it would be prudent to note that no significant
deterioration in hearing was detected in any patient of
group-B at the end of 6 months.
In this study 17 patients also had tinnitus. And a his-
tory of vertigo was recorded in 39 of the 100 patients.
4. Discussion
Goitre is defined as an enlargement of thyroid gland.
Worldwide about 90% of cases are due to iodine defi-
ciency. In countries that use iodized salt, Hashimoto’s
thyroiditis is the most common cause [17]. Further it is
important to note that over a period of time, patients of
goitre due to lack of iodine can develop hypothyroidism
[17]. Hence, the evaluation of hearing in goitrous hypo-
thyroidism assumes clinical importance.
In our study group of goitrous hypothyroid we found
that 39% of patients had some hearing loss. Out of these
15% cases had sensorineural hearing loss; a conductive
hearing loss was seen in only 8% cases, the remaining
13% recorded a mixed hearing loss. The medical litera-
ture quotes a hearing loss of 25% for patients with ac-
quired hypothyroidism and 35% - 50% for congenital
hypothyroidism [6,7]. Moreover an incidence of 30% -
40% for sensorineural hearing loss has been reported for
myxoedema in medical text [2]. From the above account
it is clearly evident that patients with goitrous hypothy-
roidism have a comparable hearing loss (39%), but the
incidence of sensorineural loss is less. Nevertheless, a
Copyright © 2013 SciRes. IJOHNS
Table 5. Statistical analyses of hearing improvement with
l-thyroxine treatment.
Average hearing threshold in db
(pure tone audiometry)
(Patients with
deafness) Group-A1
(Pre treatment)
(Post treatment)
1. 71.33 68.33
2. 40 36.66
3. 30 28.33
4. 60 51.66
5. 53.33 45
6. 68.33 61.66
7. 35 31.66
8. 68.33 65
9. 70 60
10. 56.67 53.33
11. 46.67 36.66
12. 46.67 41.66
13. 45 43.33
14. 80 75
15. 78.33 73.33
16. 66.67 55
17. 41.66 36.66
18. 41.67 36.66
19. 41.67 38.33
20. 50 43.33
21. 85 80
22. 45 38.33
23. 48.33 38.33
24. 76.66 75
25. 38.33 36.66
26. 40 36.66
27. 55 46.66
28. 68.33 60
29. 60 55
30. 65 61.66
31. 61.67 53.33
32. 58.33 51.66
33. 30 36.66
34. 58.33 51.66
35. 65 56.66
36. 40 30
Statistical Calculations
Mean 55.2308 49.7183
Standard Deviation [SD] 14.7682 14.0448
Standard Error of mean [SEM] 2.4614 2.3408
*Confidence Interval: The mean group-A1 minus Group-A2 = 5.5125; 95%
confidence interval: 4.3466 to 6.6784; *Intermediate values used in calcu-
lations: t = 9.5986, df = 35, standard error of difference = 0.574; *P value
and statistical significance: Two tailed P value = <0.0001, which is ex-
tremely significant.
sensorineural element tends to predominate (28%) in
these cases of goitrous hypothyroidism too. Also most of
the patients had a moderate or moderately severe hearing
loss (Table 2).
In this study we recorded an overall statistically sig-
nificant hearing improvement after thyroxine treatment
(Table 5). But the author’s would like to highlight that a
significant 10 db improvement was observed in only 5
cases i.e. only about 13% cases had an objective audi-
ological improvement (Table 3), though many cases
claimed a subjective improvement in hearing. And one
case also had deterioration in hearing. Further it was ob-
served that the thyroxine treatment influences the hearing
maximally at 1000 Hz, the frequency at which 31 ears
had a significant gain of 10 db or more (Table 4). There
are diverse views regarding improvement in hearing in
hypothyroid patients with thyroxine treatment. Studies by
Vent Hoff W (1979) [9], Rubeinstein M et al. (1974)
[10], Howarth AF et al. (1956) [11] and Anand VT et al.
(1989) [12] have reported an improvement in hearing
following thyroxine therapy. On the other hand studies
by Post JT (1964) [13], DeVos JA (1963) [14], Parving
A et al. (1973) [3] and yet another study by Parving A et
al. (1983) [4] have not reported any significant im-
provement in hearing post treatment with thyroxine. A
recent study which analyses Meniere’s disease and thy-
roid dysfunction also found no statistically significant
difference between prevalence, pattern and severity of
hearing loss between patients of Meniere’s disease taking
thyroxine supplements and patients who were not [5].
The exact Pathophysiological changes leading to hear-
ing loss in hypothyroidism have not yet been unveiled. It
is believed that hypothyroidism leads to decrease in cell
energy production, compromising the microcirculation
and consequently the metabolism and oxygenation of the
involved organ. In the case of hearing loss this affects the
inner ear structures: stria vascularis and organ of corti
[18,19]. Thyroid hormone also controls protein synthesis,
myelin production and enzymes and the level of lipids in
the central nervous system. In addition, T4 also acts as a
neurotransmitter. Thus it is speculated that in hypothy-
roidism hearing impairment can originate in the cochlea,
central auditory pathway and/or in the retrocochlear re-
gion [20]. Moreover, in most of the studies brainstem
electric response does not show significant reversal fol-
lowing L-thyroxine therapy [4,12,14]. Thus it is widely
accepted that improvement in hearing following levothy-
roxine therapy is attributed to improved general condi-
tion of the patient resulting in improved co-operation in
psycho-acoustic testing, the so called functional improve-
ment in central deafness [4,12,14]. The histological ex-
amination of temporal bones in these patients has also
failed to show accumulations of glycoaminoglycans [4,
21,22]. It would however be imperative to note that con-
Copyright © 2013 SciRes. IJOHNS
ductive hearing loss in hypothyroidism is secondary to
Eustachian tube mucosal oedema [23].
Although it was not the endeavour of this study to
analyse the vestibular changes in goitrous hypothyroid-
ism, the authors would like to highlight that almost 39%
cases had a history of vertigo, out of which 26 patients
had an subjective improvement after levothyroxine ther-
apy at the end of 6 months. In this context it would be
important to note that the medical text mentions that al-
most 66% of patients of hypothyroidism suffer from ver-
tigo [2]. Tinnitus too was present in 17 cases. Nine of
these cases recorded a subjective improvement in form of
decrease in the duration and intensity of the tinnitus.
Thus a joint involvement of cochlear and vestibular sys-
tem is also seen in goitrous hypothyroidism as has been
reported for other metabolic disorders [24]. The authors
would also like to highlight that no case of Meniere’s
disease i.e. the classical triad of vertigo, deafness with
tinnitus was recorded in this case series, though the lit-
erature reports an intrinsic relationship between hypo-
thyroidism and Meniere’s disease (a recent study quotes
a prevalence of 32%) [5].
Interpretations of these results must take into consid-
eration the limitations of our analysis. As data from a
single tertiary health care centre was used, it reflects the
experience of our geographical area and may not be gen-
eralized. Information from observational studies can be
subject to potential biases (e.g. selection bias) and con-
founding. Critics may contend that 6 months follow-up
period is short. Furthermore, the results were not ascer-
tained blindly. Last but not the least; we were unable to
discern the reason for this decreased sensorineural hear-
ing loss in goitrous hypothyroidism. This could be due to
the demographic profile of our patients. But then the au-
thors would like to emphasise that the very cause of
hearing loss in hypothyroidism is debatable and contro-
versial. Nevertheless, the strength of this study lies in its
prospective character and independent statistical valida-
tion, which allowed for accurate assessment of data with-
out depending upon recalled information in accordance
with evidence based medicine. The authors would like to
highlight that this study represents the largest series of
patients on hypothyroidism. The true value of this study
in context of existing literature lies in the audiological
evaluation of patients belonging to the subgroup of goi-
trous hypothyroid, hitherto unreported in medical litera-
5. Conclusion
In conclusion, the patients of goitrous hypothyroidism
have a lower rate of sensorineural hearing loss as com-
pared with other patients of hypothyroidism. Further, this
study delineates a definitive role of L-thyroxine therapy
in improvement of hearing in patients suffering from
goitrous hypothyroidism. We believe that conclusions of
this study can serve as a guide for future research on the
cited subject.
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