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Speech perception both pre- and postoperatively was
measured in quiet using consonant–nucleus–consonant (CNC)
words as well as AzBio sentences and administered at 60 dB A.
Hearing in Noise
Hearing in background noise with various signal-to-noise
ratios (SNR) was also tested with speech from the front and
noise incident from the front, the better hearing ear, and the CI
ear. Bamford–Kowal–Bench sentence-in-noise (BKB-SIN)
(Etymotic Research 2005, Elk Glove Village, IL, U.S.A.)
testing was administered for four adult subjects, whereas adap-
tive hearing in noise test (HINT) testing was administered for
the remaining six adult subjects.
BKB-SIN is designed to assess sentence recognition in noise
and consists of 36 lists of sentences presented in 4-talker babble
noise. The sentences are presented at 65-dB SPL and the level of
the noise is varied in 3 dB steps at fixed SNR beginning at
þ
21 dB SNR (easy) descending to 6 dB SNR (hard) to obtain
a speech reception threshold where the subjects can repeat key
words 50% of the time (SNR-50); therefore, a lower score is
indicative of better performance. The test was performed in the
sound field in each ear individually and in the sound field in
three conditions: speech front/noise front, speech front/noise
right, speech front/noise left (n
¼
4) or using Direct Connect
(n
¼
6) as noted above. Scores are indicated as dB SNR. In those
patients tested in both sound field and using Direct Connect,
results were found to be equivalent.
As DC was integrated into our evaluations, we began using
adaptive HINT testing in place of BKB-SIN for evaluating
hearing in noise sentences on all new patients as well as for
subsequent evaluations of previously implanted patients.
Localization
Localization testing was performed with the Direct Connect
system as described above for five adult patients. A broadband
noise from 1 of 12 virtual locations in the rear hemifield with
locations numbered 1 through 12 on a response sheet, from right
to left, and positioned to represent an arc from 97.5 degrees (on
the right) to 262.5 degrees (on the left) with 15 degrees
separations between source locations. The task involves a
verbal response corresponding to the perceived location of
the sound. Localization testing is reported as the degrees root
mean squared (RMS) error.
RESULTS
Adult Subjects, n
U
12
Postoperative data were available for 10 adult patients
(Table 3) as one transitioned care to another center
whereas another was not a native English speaker. Data
from most recent postoperative evaluation (3.4 yr 1.8)
were used for performance comparison relative to pre-
operative data. Table 4 demonstrates individual subject
outcomes data.
Speech Perception
There was significant improvement in CNC word
scores in the implanted ear with an average benefit of
54% (SE 8.4),
p
¼
0.001 in seven adult patients who
underwent this test. Improvement in sentence scores on
AzBio in quiet relative to the SSD ear was on average
82.5% (SE 14.5); however, this was not statistically
significant (
p
¼
0.11) as there were only two matched
pairs. Sound field and direct connect results were equiv-
alent in all patients.
Hearing in Noise
Speech-in-noise using binaural hearing BKB-SIN or
adaptive HINT tests demonstrated that when noise was
presented to the SSD/CI ear (speech front), the signal-to-
noise ratio significantly decreased with an average
reduction of 2.0 dB SNR (SE 0.8),
p
¼
0.047 in nine
TABLE 3.
Outcomes across clinical time points
Category
n
Preop (SD)
n
1 year
Postop (SD)
n
Most recent
Postop
Preop vs Most Recent
Postop
p
Value
CNC words (% score)
CI ear
9
2.9 (5.6)
8
55.4 (16.9)
7
57.7 (21.1)
0.001
Bilateral
4
98.0 (2.3)
8
98.0 (1.4)
7
95.7 (4.1)
0.594
AZ BIO (quiet)
CI ear
5
6.6 (9.2)
3
95.0 (4.6)
2
92.0 (7.1)
0.111
Bilateral
5
100 (0)
3
100.0 (0)
2
100.0 (0)
—
HINT/BKB-SIN-noise front (SNR)
Bilateral
10
1.8 (1.9)
8
2.4 (1.0)
7
2.1 (1.3)
0.960
HINT/BKB-SIN-noise CI ear (SNR)
Bilateral
10
2.4 (2.7)
8
6.6 (2.5)
7
5.3 (3.0)
0.047
HINT/BKB-SIN-noise better ear (SNR)
Bilateral
10
0.3 (3.1)
8
2.5 (2.0)
7
3.7 (1.5)
0.005
Localization (degrees RMS)
CI ear
0
—
5
54.0 (11.6)
5
67.0 (15.1)
—
Bilateral
4
42.5 (7.7)
5
47.2 (9.4)
5
45.0 (16.6)
0.205
Speech perception of adult SSD patients who underwent cochlear implantation.
p
values calculated using dependent
T
test. ‘‘
—
’’ indicates measurement could not be calculated secondary to lack of matched pairs or the
standard error of the difference being zero. As given in Table 1, the average time from surgery to the most recent post-op visit (
>
1 yr post-op)
is 3.4 years (SD 1.8). AzBio (quiet) indicates Arizona biomedical sentences in quiet condition; BKB-SIN, Bamford–Kowal–bench sentence-in-
noise test; CI, cochlear implant; CNC words, consonant–vowel nucleus–consonant words; HINT, hearing in noise test; RMS, root mean square;
SNR, signal-to-noise ratio.
D. R. FRIEDMANN ET AL.
Otology & Neurotology, Vol. 37, No. 2, 2016
127