**6.1 Results and analysis**

Road traffic accidents (RTA) were the most common cause of Minor head injury as seen in all studies. The incidence of road traffic accidents in age groups 20-50 years, in our study, (Fig-5) was similar to the study done by Ludwig podoshin and M R Abd AL-Hady. A vast majority (75%) of the RTA's (Road traffic accidents) (Fig-6) were two wheeler accidents and none wore helmets at the time of accident.

Majority (83%) were males and 66% were between ages of 20-50 years.

Hearing Loss in Minor Head Injury 147

Out of 60 patients 73% were asymptomatic, 15% complained of vertigo, 10% complained of

38%(46)

NORMAL SNHL CHL MIXED

> norm al m ild

m o d e ra te

severe

m o d e ra te ly s e v e re

Out of 60 patients (120 ears tested), 38 % had normal hearing, 40% had sensorineural hearing loss, 7% had conductive hearing loss, and 15 % had mixed hearing loss (fig -8).

Pure tone audiometry assessment of hearing immediately post trauma with respect to frequencies affected revealed that hearing loss was mainly in the high frequency region with greatest loss noticed at 4000 Hz and 8000 Hz (Fig-9). Significant hearing improvement on PTA was found at all the four frequencies with in three months after trauma , 1000Hz (p-

p ta 1 0 0 0 p ta 2 0 0 0 p ta 4 0 0 0 p ta 8 0 0 0

hearing loss, and 2% complained of tinnitus (Fig-7).

15%(17)

Fig. 8. Hearing loss in patients with MHI

7%(8)

40 %( 49)

Fig. 9. Pure tone audiometry

Fig. 5. Age amd sex distribution

Fig. 6. Mode of injury

Fig. 7. Symptoms

FEMALE MALE

**AGE AND SEX DISTRIBUTION**

0-10 11-20 21-30 31-40 41-50 51-60 **AGE**

Fig. 5. Age amd sex distribution

**NUMBER OF** 

**PATIENTS**

Fig. 6. Mode of injury

0

73%(44)

RTA(89%) FALL FROM

10%(6)

HEIGHT(7%)

15%(9)

2%(1)

HIT BY BRICK(2%)

BULL GORE(2%)

HEARING LOSS

ASYMPTOMATIC

VERTIGO TINNITUS

10

20

30

40

50

60

Fig. 7. Symptoms

Out of 60 patients 73% were asymptomatic, 15% complained of vertigo, 10% complained of hearing loss, and 2% complained of tinnitus (Fig-7).

Fig. 8. Hearing loss in patients with MHI

Out of 60 patients (120 ears tested), 38 % had normal hearing, 40% had sensorineural hearing loss, 7% had conductive hearing loss, and 15 % had mixed hearing loss (fig -8).

Fig. 9. Pure tone audiometry

Pure tone audiometry assessment of hearing immediately post trauma with respect to frequencies affected revealed that hearing loss was mainly in the high frequency region with greatest loss noticed at 4000 Hz and 8000 Hz (Fig-9). Significant hearing improvement on PTA was found at all the four frequencies with in three months after trauma , 1000Hz (p-

Hearing Loss in Minor Head Injury 149

Fig. 11. Pure tone audiometry showing progression of hearing loss affecting frequency of 4000hz,8000hz in patient with left frontal bone fracture. Absence of DPOAEs at 4000hz from

the time of trauma

value 0.014) , 2000Hz (p-value 0.006), 4000Hz (p-value<0.001), and 8000Hz (p-value 0.002)( Fig-10) ,( Fig-11),(Fig-12) .

Fig. 10. Serial Pure Tone audiometry at 1000Hz,2000Hz,4000Hz,8000Hz over a period of six months

DPOAEs are present across most frequencies at and above 1000Hz in 99 to 100% of ears with normal hearing and they are absent when sensorineural hearing loss exceeds 40-50dB which was similar in our study. No studies were found in literature where DPOAE was assessed in minor head injury.

It was seen that DPOAE was absent in 38.6% at 1000Hz, 36% at 2000Hz, 29.8% at 4000Hz in patients even with normal PTA thresholds after mild head injury.

In case of Mild hearing loss on PTA, there was absence of emissions in 70% at 1000 Hz, 69% at 2000Hz, 83% at 4000Hz. This would suggest that damage to outer hair cells becomes more pronounced when there is manifest hearing loss on PTA. In few cases with normal hearing, DPOAEs were absent through out the evaluation time period suggesting irreversible damage to outer hair cells (Fig13, 14, 15).

value 0.014) , 2000Hz (p-value 0.006), 4000Hz (p-value<0.001), and 8000Hz (p-value 0.002)(

1 2 3 4

1 2 3 4

PTA\_4K no rma l m ild m ode rate m ode rate ly se ve re seve re

> PTA\_2K n o rm al m ild m od e ra te m od e ra te ly s ev er e se ve re

Count

120

100

8 0

6 0

4 0

2 0

0

VISIT\_NO

7 0

Fig. 10. Serial Pure Tone audiometry at 1000Hz,2000Hz,4000Hz,8000Hz over a period of six

PTA\_1K normal mild moderate moderately severe severe

PTA\_8K normal mild mo derate mo derate ly sev ere se vere VISIT\_NO VISIT\_NO

Count

DPOAEs are present across most frequencies at and above 1000Hz in 99 to 100% of ears with normal hearing and they are absent when sensorineural hearing loss exceeds 40-50dB which was similar in our study. No studies were found in literature where DPOAE was assessed in

It was seen that DPOAE was absent in 38.6% at 1000Hz, 36% at 2000Hz, 29.8% at 4000Hz in

In case of Mild hearing loss on PTA, there was absence of emissions in 70% at 1000 Hz, 69% at 2000Hz, 83% at 4000Hz. This would suggest that damage to outer hair cells becomes more pronounced when there is manifest hearing loss on PTA. In few cases with normal hearing, DPOAEs were absent through out the evaluation time period suggesting irreversible

patients even with normal PTA thresholds after mild head injury.

Fig-10) ,( Fig-11),(Fig-12) .

months

Count

120

Count

100

80

60

40

20 0

minor head injury.

VISIT\_NO

1 2 3 4

1 2 3 4

damage to outer hair cells (Fig13, 14, 15).

Fig. 11. Pure tone audiometry showing progression of hearing loss affecting frequency of 4000hz,8000hz in patient with left frontal bone fracture. Absence of DPOAEs at 4000hz from the time of trauma

Hearing Loss in Minor Head Injury 151

1 2 3 4

DP\_3K no yes

DP\_4K no yes

As the hearing improved oto-acoustic emissions were detectable, however in cases where the hearing loss progressed, emissions could not be recorded. Changes in DPOAEs were found to be statistically significant only at 3000 Hz (p value-0.002) and 4000Hz (p value-

1 2 3 4

Dix-Hallpike positional test was positive in three patients for whom Epley's repositioning maneuver was done and rests of the patients were treated with labyrinthine suppressants.

On examination hemotympanum was noticed in 2 patients which resolved over a period of three months. 1 patient presented with laryngeal trauma, rest of the patients had bleeding

Fig. 14. DPOAE at 3000kz

Count

70

60

50

40

30

20

10 0

VISIT\_NO

VISIT\_NO

Fig. 15. DPOAE at 4000kz

Count

0.003), in mild head injury.

One patient complained of tinnitus.

either from the nose or the ear.

Fig. 12. Pure tone Audiometry and DPOAEs showing conductive hearing loss post trauma which returned to normal over a period of six months, but continues to have absent emissions at 4000 Hz, 6000 Hz

Fig. 13. DPOAE at 1000kz

Fig. 12. Pure tone Audiometry and DPOAEs showing conductive hearing loss post trauma

1 2 3 4

DP\_1K no yes

which returned to normal over a period of six months, but continues to have absent

emissions at 4000 Hz, 6000 Hz

Fig. 13. DPOAE at 1000kz

VISIT\_NO

Count

80

60

40

20

0

VISIT\_NO

Fig. 14. DPOAE at 3000kz

Fig. 15. DPOAE at 4000kz

As the hearing improved oto-acoustic emissions were detectable, however in cases where the hearing loss progressed, emissions could not be recorded. Changes in DPOAEs were found to be statistically significant only at 3000 Hz (p value-0.002) and 4000Hz (p value-0.003), in mild head injury.

Dix-Hallpike positional test was positive in three patients for whom Epley's repositioning maneuver was done and rests of the patients were treated with labyrinthine suppressants. One patient complained of tinnitus.

On examination hemotympanum was noticed in 2 patients which resolved over a period of three months. 1 patient presented with laryngeal trauma, rest of the patients had bleeding either from the nose or the ear.

Hearing Loss in Minor Head Injury 153

Delayed facial nerve paresis was seen in one patient who presented with history of bull gore

This prospective study was done in a tertiary care teaching hospital to look at the incidence of hearing loss in patients who sustained minor head injury. The behavior of hearing loss was evaluated by serial assessment of hearing. Road traffic accidents (RTA) were the most common cause of Minor head injury as seen in all studies. The incidence of road traffic accidents in age groups 20-50 years, in our study, was similar to the study done by Ludwig podoshin and M R Abd AL-Hady. Whereas in the study done by Griffith, the majority were

Two wheeler accidents were found to be the commonest cause of RTA causing minor head injury in our study, whereas another study ( George .G.Browning at al 1982) reported that assault /fight was the major etiology causing minor head injury. 75% of the RTA's were two wheeler accidents and none of them were wearing helmets at the time of accident. In about 40% of our patient's consumption of alcohol would have contributed to the road traffic

Symptoms of hearing loss were found in only 10% of patients which is in agreement with Harold F.Schuknecht (1956) and Kazumi Makashima et al (1975) due to the involvement in high frequency region. The symptoms of vertigo were found to be 15% which is low as compared with Toglia JU et al (1970) who reported an incidence of 61% and Rosalyn et al (1995) who reported 95% of patients with symptoms of vertigo . Additionally a low Incidence of tinnitus was observed which is in agreement with Griffith. The incidence of Hearing loss in our study is 62% which is in agreement with a previous study Griffith (56%)

The commonest type of hearing loss was sensorineural loss confined to high frequencies. The degree of hearing loss determined the out come, and it was found in our study that patients who had moderate to severe hearing loss at the time of injury had a poorer prognosis as compared to those with normal hearing. Like the results of other studies temporal bone fractures had a higher incidence of hearing loss as compared to other facial

In our study in India, Road traffic accidents (RTA) were the most common cause of Minor head injury. 75% of the RTA's were two wheeler accidents and none of them were wearing helmets at the time of accident. In about 40% of our patient's consumption of alcohol might

Only 10% of patients complained of hearing loss ,however on evaluation 62% were found to have hearing loss. The commonest type of hearing loss was sensorineural loss confined to high frequencies. The prognosis was poor if the hearing loss was more severe. The degree of hearing loss determined the outcome, and it was found in our study that patients who had moderate to severe hearing loss at the time of injury had a poorer prognosis. Temporal bone fractures have a higher incidence of hearing loss, the symptoms of vertigo was found to be 15%. Incidence of tinnitus is low after minor head injury. DPOAE assessment at 3000 Hz

injury which recovered within 3 months.

**7. Conclusion** 

seen in late teens.

with males being most affected.

have contributed to the road traffic accidents.

accident.

bone fractures.

Bleeding from the ear was noticed to be due to laceration in the external auditory canal. Patients having ear bleeding were called after a week for auditory assessment, no active intervention was needed. 1 patient had ottis externa which was treated conservatively.

Fig. 16. Distribution of fractures

Out of 60 patients a total number of 15 patients were found to have skull fractures (fig-16).

Of 5 patients with frontal bone fractures bilateral hearing loss was noticed in all the patients, of which mixed hearing loss improved but did not become normal.

In patients who sustained temporal bone fractures, mixed fractures were seen in two patients, one patient had longitudinal fracture, and one had transverse fracture. Sensorineural hearing loss was found in four ears, mixed hearing loss was found in one ear, conductive hearing loss was noticed in one ear, and two ears were found to be normal.

Sensorineural hearing loss was noticed in the patient who sustained a fracture of the occipital bone.

Out of the three patients who sustained parietal bone fractures two patients were found to have normal hearing, the third patient had sensorineural hearing loss in one ear which became normal and mixed hearing loss in the other ear that improved.

Bilateral sensorineural hearing loss was detected in patients who sustained facial bone fractures.

Only one patient with parietal bone fracture with normal hearing complained of vertigo in which positional test was negative and was treated conservatively.

Out of the four patients who fell from a height three patients had normal hearing and one had conductive hearing loss. Parietal bone fracture was detected in one patient who had normal hearing. Hearing loss progressed in one patient.

Delayed facial nerve paresis was seen in one patient who presented with history of bull gore injury which recovered within 3 months.
