150 / 232
adult patients tested. When noise was presented to the
better hearing ear (speech front), the signal-to-noise ratio
significantly decreased with an average reduction of
4.6 dB (SE 1.0),
p
¼
0.005.
Localization
No significant difference in sound localization was
found when comparing preoperative data to 1-year post-
operative data with regards to root mean square (RMS)
error values (n
¼
4 matched pairs,
p
¼
0.61). Further-
more, no difference was found when comparing preop-
erative data to postoperative data from more than 1 year
after surgery (n
¼
2 matched pairs,
p
¼
0.21).
Subjective Assessment
All adult subjects were able to integrate the signal from
the implanted ear (electrical) with the acoustic signal,
without deterioration in speech understanding in their
better hearing ear. All patients with tinnitus reported
suppression since device activation.
Pediatric Subjects (n
U
4)
Our institutional experience consists of four pediatric
SSD patients implanted to date. The first child was
implanted at the age of 10, and is now 14 years old.
She has enlarged vestibular aqueduct (EVA) and a long
duration of deafness in her left ear. Preoperatively, she
obtained 0% on CNC words in the effected ear alone. Her
score at the 1-year post-op interval was 18% but has since
dropped to 6% by year three. Concurrently, there has
been a progressive decline in the nonimplanted ear alone
from 98 to 80% at her most recent evaluation. At 3
months and 1 year, BKB-SIN scores were significantly
improved in all three conditions compared with preop-
erative values, but have since declined to poorer than
preimplant scores. Although she initially wore the device
regularly, she now wears it only in school
—
though she
does report subjective benefit during use as duly noted by
her parents and teachers. Evidence from our experience
with SSD patients after cochlear implantation is that
although the quality of the auditory percept may not
be acceptable, as they lose hearing in the nonimplanted
hearing ear (as expected in patients of EVA, for
example), they begin to better integrate and interpret
the CI signal. This has not been the case to date with this
patient as she has been wearing her device with less
regularity over time. When questioned, she seems too
focused over concern for her declining acoustic hearing
to recognize the long-term benefit of using her implant
more regularly.
The second pediatric impatient was implanted at the
age of six and had PBK-word scores of 20%, HINT-Q
was 76% and HINT-N was 49% in implant only con-
dition at 3-months poststimulation. Bimodal scores were
100% showing that the signal was not being degraded by
the addition of an electrical stimulus to the normal
hearing ear. Interestingly, despite the apparent increase
in performance, he only wears the CI in school and
sometimes complains that it ‘‘bothers’’ the good ear.
TABLE 4.
Individual subject data
CNC Words
Score (% score)
HINT/BKB-SIN,
Noise Front (SNR)
HINT/ BKB-SIN,
Noise CI Ear (SNR)
HINT/ BKB-SIN,
Noise Better
Ear (SNR)
Localization
(degrees RMS)
ID
Age at
Implantation
Duration of
Deafness (yr)
Etiology
PTA of
Normal
Ear
PTA of
SSD Ear
Preop,
CI Ear
One Year
Postop,
CI Ear
Preop,
Bilateral
One Year
Postop,
Bilateral
Preop,
Bilateral
1 Year
Postop,
Bilateral
Preop,
Bilateral
1 Year
Postop,
Bilateral
Preop,
Bilateral
1 Year
Postop,
Bilateral
Device
1
58
0.92
SSNHL
17
95
0
69
0.6
4.0
1.4
7.4
4.8
3.1
46
60
Nucleus
2
64
21
Me´nie`re’s
18
83
0
24
6.5
3.3
3.5
8.6
0.3
3.1
48
44
Nucleus
3
65
1.75
SSNHL
5
78
8
63
0.5
1.9
5.5
7.8
2.3
1.0
45
35
Nucleus
4
27
1.08
SSNHL
0
100
0
49
1.9
2.9
0.4
8.3
5.5
4.3
31
45
Nucleus
5
30
1
SSNHL
20
85
0
76
3.0
1.3
5.5
4.5
3.5
3.8
— —
Nucleus
6
62
0.75
SSNHL
23
85
2
76
0.1
4.0
1.5
5.5
1.5
4.5
— —
Nucleus
7
36
0.42
COM 10
112
0
66
1.5
3.0
6.0
6.3
3.5
0.8
— —
Nucleus
8
56
3.42
SSNHL
17
90
0
84
0.5
1.6
0.5
1.5
0.8
4.5
— —
Nucleus
9
47
2.42
CPA lesion
7
73
16
54
2.0
1.0
0.5
1.3
1.0
0.3
— —
AB
10
62
1.58
SSNHL
10
98
—
42
1.5
2.0
2.8
8.3
1.4
4.8
—
52
Nucleus
Individual adult subject outcomes data after SSD cochlear implantation.
Pure-tone average (PTA) was calculated using air conduction lines at 0.5, 1, and 2 kHz. ‘‘
—
’’ indicates that data were unavailable. For subjects 6 and 8 in table (‘‘ID’’ column), data from 3
years post-op were used as 1 year post-op data were unavailable.
AB indicates Advanced Bionics; COM, chronic otitis media; RMS, root mean square; SD, standard deviation; SNR, signal-to-noise ratio; SSNHL, sudden sensorineural hearing loss.
SINGLE-SIDED DEAFNESS COCHLEAR IMPLANTATION
Otology & Neurotology, Vol. 37, No. 2, 2016
128