Childhood deafness poses problems in developing countries

Editor—Childhood deafness is an important disorder globally affecting more than 62 million children younger than 15 years. Two thirds reside in developing countries.¹ Although many studies have been reported on the aetiology of deafness, the age/mode of detection and intervention in many developing countries is unknown.

Our questionnaire based study of 363 parents of children attending the only public schools for the deaf in Lagos, Nigeria, with a total enrolment of 429, showed that parents were predominantly (81%) the first to suspect or detect hearing difficulty in their children (table). Parental suspicion occurred mostly at 12-24 months, compared with 8-14 months in developed countries.²,³ Only 12% suspected hearing difficulty by age 6 months. The commonest mode of detection was a child's failure to respond to sound (49%). Speech/language defects or unintelligible speech were least associated with hearing difficulty (1%).

Table 1.

Responses to parental questionnaire (n=363)

Question	No (%)	95% CI
Who first detected or suspected your child's problem (n=357):
Parent	289 (81)	76.5 to 84.9
Relation	18 (5)	3.1 to 8.0
Neighbour	13 (3)	2.0 to 6.3
Doctor/health worker	31 (9)	6.1 to 12.2
Friend	4 (1)	0.4 to 3.0
Other	2 (1)	1.1 to 2.2
When did you first notice that your child had hearing problem (n=359):
0 - 6 months	42 (12)	8.7 to 15.6
6 months - 1 year	89 (25)	20.5 to 29.7
1 - 2 years	142 (40)	34.5 to 44.8
2 - 5 years	70 (19)	15.6 to 24.1
After 5 years	16 (4)	2.7 to 7.3
How did you first notice that your child had hearing problem (n=314):
Failure to respond to sound	153 (49)	43.1 to 54.4
Failure to respond to own name	58 (18)	14.4 to 23.3
Observed speech and language delay	50 (16)	12.2 to 20.6
Observed speech and language defects or unintelligible speech	3 (1)	0.2 to 3.0
Failure to obey simple commands e.g. No, Come, Sit down, Bye-bye etc.	33 (11)	7.4 to 14.6
Other	17 (5)	3.3 to 8.7
What did you first do to help your child (n=315):
Consulted a medical doctor	243 (77)	72.1 to 81.7
Sought spiritual healing	15 (5)	2.8 to 7.9
Took child to school for the deaf	24 (8)	5.0 to 11.3
Waited to see if the problem would resolve	24 (8)	5.0 to 11.3
Did not know what to do	4 (1)	0.4 to 3.4
Other	5 (1)	0.6 to 3.9
Has your child ever used hearing aids (n=247):
Yes	49 (20)	15.1 to 25.4
No	198 (80)	74.6 to 84.9

As in developed countries, doctors were most commonly consulted for help (77%). However, most children (80%) were not provided with hearing aids even where appropriate, granted that cochlear implantation was improbable. Parents were often told that their children were “slow starters” and would outgrow the speech delays, only to be enrolled in schools for the deaf when this optimism failed. Ironically, only 6% were so enrolled by age 6 years (mean age of enrolment 10.3 years). This protracted delay especially for the 363 hearing parents may be indicative of their preference for spoken rather than sign language after initial denial and grief.

Screening the hearing of newborn babies allows prompt detection of congenital and early onset deafness, for optimal development of speech and language development.⁴ Until such a programme becomes available, doctors should follow the lead from parental suspicion especially as part of ongoing surveillance to detect children with late onset deafness. The World Health Organization's current initiatives for affordable hearing aids and support services in developing countries should encourage the development of auditory-verbal intervention services.⁵