Two moderately robust. However, at 1 and 2

Two studies are reported which
compared the threshold estimation in auditory steady state response (ASSR)
tests with evoked auditory brainstem responses (ABRs) using click or tone burst-evoked.

Study1:
comparison of ASSR with ABR results

This study demonstrated that the threshold
estimation using the ABR and ASSR could be used to predict the pure-tone
threshold in infants and children. To obtain the
results, Behavioral Threshold Tests, ABR Threshold Tests and ASSR Threshold
Tests were conducted. 

 

Result:  

The discrepancy
between behavioral and evoked potential threshold was generally smaller for
ASSR than for ABR. The correlations of c-ABR with pure-tone thresholds were
moderately robust. However, at 1 and 2 kHz, the pure tone-ABR correlation
coefficients slightly exceeded those for the ASSR.

   

Discussion: 

–         
These
data indicate that both c-ABR and ASSR threshold estimates can be used to
predict pure-tone threshold for infants and children.

–         
The differences between the ABR and ASSR
correlation coefficients were small. In addition, both click ABR and ASSR have
strong and statistically significant correlations.

–         
The
correlations between the c-ABR threshold and the ASSR thresholds were also
statistically significant. 

Strengths: 

–         
In this study ABR, ASSR, and behavioral threshold correlations were addressed. However,
the previous studies were only address ASSR and behavioral threshold
correlations.

Weakness: 

 

–         
Differences in thresholds when measured in
the ear canal for the adult and infant.

–         
More than
half of the sample are sensorineural hearing loss, so the
sample distribution was not equal.

–         
Some observer may have bias to the response
based on the audiometric result.

 

Study2:
Direct comparison of ASSR and tone bursts evoked ABR

This study provided evidence that there was
similarity in threshold estimation when automatic detection was used in ABR and
ASSR algorithm. However, the threshold estimation varied with frequency,
stimulus rate, and detection method.

ASSR tests were carried out using 500- and
4000-Hz. Response Detection include visual detection and automatic detection. 

 

Result: 

Thresholds for 500 Hz were elevated in
comparing with 4000 Hz. In regards to stimulus type, threshold
for the tone bursts were elevated.

 

Discussion: 

–         
Visual
detection of the 500-Hz tone burst ABR resulted in significantly lower threshold
estimates compared to other measures at 500 Hz, and the 500 Hz ASSR at 74 Hz
resulted in the highest threshold estimates.  

–         
Visual detection
of tone
burst ABR at 4 kHz also resulted in the lowest
threshold estimate, but this was not significantly different from the estimate
obtained for ASSR at 95 Hz. 

Strengths: 

–         
Previous
studies comparing ASSR to tone burst ABR have employed visual detection alone for
ABR threshold estimates and have only compared tone ABR to ASSR at one
frequency. However, this study includes findings at more than one frequency. 

–         
All
participants had normal pure tone thresholds and normal results in
tympanometry.

Weaknesses: 

–         
ASSR is
not approved by Food and Drug Administration (FDA). 

–         
Most of
the participants slept during testing ASSR and the thresholds were lower. 

–         
Only one
ear was tested for each participant in both ABR and ASSR 

–         
No
formal assessment was made of subject status during the experimental
procedures. 

–         
Difficulties remain in comparing threshold
estimates for tone ABR and ASSR because of the difference in stimuli used. 

 

What did I
learn:

–         
Frequency specificity, response generators, the
effects of hearing loss, and automatic detection algorithms should be
considered when comparing the two evoked potentials.

–         
A
disadvantage of ABR is the subjective nature of response detection. However, ASSR
use objective detection using a set of statistical criterion previously
obtained.