Neuroscience Poster Session
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Results
The results we obtained in the subjective identification of intensities and therefore of thresholds in the four different used types of logon stimuli gave us different values on the basis of the studied frequency, although all them were lower than 40 dB p.e. SPL. (Table 2)
Table 2. Subjective audiometry thresholds with logon stimuli of 500 Hz, 1000 Hz, 2000 Hz and 4000 Hz in dB p.e. SPL
500 Hz 1000 Hz 2000 Hz 4000 Hz
Mean 30,57 25,31 25,38 29,27
SD 3,26 4,06 4,78 4,61
The first step for the valuation of the data obtained in evoked potentials, was the same waves that we can be obtained in the recordings with click after stimulation with the different logon stimuli (Figure 2).
Fig. 2: Recording morphology at 100, 80, 60 and 40 dB p.e. SPL (from top to bottom).
As a result of these recordings, it can be clearly seen that only waves I, III and V are shown to have enough clarity and reliability, although they vary according to the wave type and to the stimulus intensity for each studied frequency (Table 3).
Table 3. Waves identification percentage WAVE I dB p.e. SPL 100 80 60 40 500 Hz 88.1% 69.7% 47.9% 8.0% 1000 Hz 90.2% 74.6% 54.5% 9.3% 2000 Hz 89.9% 79.8% 65.6% 6.1% 4000 Hz 91.0% 80.5% 66.8% 8.0% WAVE III dB p.e. SPL 100 80 60 40 500 Hz 85.2% 68.4% 51.3% 9.1% 1000 Hz 87.8% 73.5% 55.6% 11.5% 2000 Hz 93.0% 75.0% 60.2% 13.6% 4000 Hz 94.5% 75.6% 65.2% 34.7% WAVE V dB p.e. SPL 100 80 60 40 500 Hz 93.6% 91.7% 90.0% 88.9% 1000 Hz 95.6% 95.7% 92.0% 89.1% 2000 Hz 98.2% 97.8% 94.0% 93.5% 4000 Hz 99.6% 98.5% 98.0% 97.1%Regarding the morphology of these recordings, there will not to be significant variations in relations to the frequency, although in 4 kHz registers, we can see that the waves II and IV often appear with intensity of 100 dB p.e. SPL.
The results we obtained for latencies showed an inverse increment in proportion to the studied frequency. (Table 4)
Table 4. Latencies results (msec.) WAVE I dB p.e. SPL 100 80 60 Mean SD Mean SD Mean SD 500 Hz 3.18 0.58 3.60 0.44 4.43 0.56 1000 Hz 2.49 0.31 2.94 0.35 3.73 0.38 2000 Hz 2.10 0.20 2.68 0.21 3.22 0.22 4000 Hz 1.77 0.10 2.16 0.16 2.72 0.15 WAVE III dB p.e. SPL 100 80 60 40 Mean SD Mean SD Mean SD Mean SD 500 Hz 5.03 0.44 5.66 0.43 6.27 0.33 1000 Hz 4.71 0.28 5.28 0.36 5.77 0.51 2000 Hz 4.21 0.18 4.57 0.17 5.08 0.17 4000 Hz 3.83 0.19 4.26 0.22 4.64 0.25 5.37 0.41 WAVE V dB p.e. SPL 100 80 60 40 Mean SD Mean SD Mean SD Mean SD 500 Hz 7.13 0.36 7.90 0.43 8.70 0.45 10.6 0.28 1000 Hz 6.58 0.28 7.07 0.33 7.73 0.48 8.50 0.38 2000 Hz 6.05 0.25 6.72 0.30 7.49 0.27 8.24 0.29 4000 Hz 5.67 0.14 6.16 0.17 6.89 0.19 7.51 0.31Apart from all the obtained data regarding latencies, we have also made an assessment of these data for interlatencies I-III, I-V and III-V for each one of the frequencies with 100 dB p.e. SPL (Table 5).
Table 5. Interlatencies results at 100 dB p.e. SPL (msec.)
500 Hz
I-III III-V I-V
L. inf. 1.95 1.50 3.74
L. sup. 2.68 2.10 4.49
Mean 2.27 1.81 4.02
SD 0.25 0.22 0.28
1000 Hz
I-III III-V I-V
L. inf. 1.98 1.34 3.60
L. sup. 2.52 2.20 4.28
Mean 2.18 1.85 3.95
SD 0.16 0.20 0.22
2.000 Hz
I-III III-V I-V
L. inf. 1.95 1.44 3.60
L. sup. 2.39 2.11 4.43
Mean 2.15 1.83 4.02
SD 0.14 0.18 0.20
4.000 Hz
I-III III-V I-V
L. inf. 1.86 1.41 3.76
L. sup. 2.35 2.12 4.30
Mean 2.08 1.73 3.96
SD 0.12 0.21 0.18
Finally, we have performed a comparative study (with 100 dB p.e SPL) of the data obtained by means of logon and click, and it has been graphically illustrated. In this graphic study, we consider the "click" as a reference value both in latency values (Figure 3, where some growing deviations in latency can be observed, reaching with 500 Hz an increment from 1 to 1,5 msec.)
Fig. 3: Comparative graph of differential latencies between logon and click to 100 dB p.e. SPL).
and interlatency values (Figure 4, where the maximum difference oscillates from +0,22 msec. To -0,14 msec.).
Fig. 4. Differential results of interlatencies between logon and click to 100 dB p.e. SPL).
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