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Pulsed 980 nm short wavelength infrared neural stimulation in cochlea and laser parameter effects on auditory response characteristics.

Wang J, Lu J, Li C, Xu L, Li X, Tian L - Biomed Eng Online (2015)

Bottom Line: The results showed that the optically evoked auditory brainstem response (OABR) had a similar waveform to the acoustically induced ABR with click sound stimulus.Our study suggests that 980 nm SWIR laser is an effective stimulus for auditory neurons activation in vivo.The evoked OABR amplitude and latency are highly affected by the laser pulse energy, while not sensitive to the pulse width variability in 100-800 μs range.

View Article: PubMed Central - PubMed

Affiliation: School of Information Science and Engineering, Shandong University, 250100, Jinan, Shandong, China. 373759703@qq.com.

ABSTRACT

Background: Auditory neural stimulation with pulsed infrared radiation has been proposed as an alternative method to activate the auditory nerves in vivo. Infrared wavelengths from 1800-2150 nm with high water absorption were mainly selected in previous studies. However, few researchers have used the short-wavelength infrared (SWIR) for auditory nerve stimulation and limited pulse parameters variability has been investigated so far.

Methods: In this paper, we pioneered to use the 980 nm SWIR laser with adjustable pulse parameter as a stimulus to act on the deafened guinea pigs' cochlea in vivo. Pulsed laser light was guided through the cochlear round window to irradiate the spiral ganglion cells via a 105 μm optical fiber, and then the laser pulse parameters variability and its influence to auditory response characteristics were studied.

Results: The results showed that the optically evoked auditory brainstem response (OABR) had a similar waveform to the acoustically induced ABR with click sound stimulus. And the evoked OABR amplitude had a positive correlation, while the OABR latency period showed a negative correlation, with the laser pulse energy increase. However, when holding the laser peak power constant, the pulse width variability ranged from 100 to 800 μs showed little influence on the evoked OABR amplitude and its latency period.

Conclusions: Our study suggests that 980 nm SWIR laser is an effective stimulus for auditory neurons activation in vivo. The evoked OABR amplitude and latency are highly affected by the laser pulse energy, while not sensitive to the pulse width variability in 100-800 μs range.

No MeSH data available.


I/O curves of OABR wave III amplitude and latency as a function of laser pulse energy. The individual data measured across animals (n = 4) are shown by the different dash lines, and the mean is shown by the solid diamond with the standard error. The laser repetition rate and pulse width were kept to 11 Hz and 200 μs. And the laser pulse energy was ranged from 0.05 to 0.5 mJ/pulse by adjusting the laser output peak power from 0.25 to 2.5 W. a The OABR wave III peak amplitude showed a monotonic increase with the pulse energy increasing from 0.05 to 0.5 mJ/pulse. b The OABR wave III latency shortened along with the pulse energy increasing
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Fig5: I/O curves of OABR wave III amplitude and latency as a function of laser pulse energy. The individual data measured across animals (n = 4) are shown by the different dash lines, and the mean is shown by the solid diamond with the standard error. The laser repetition rate and pulse width were kept to 11 Hz and 200 μs. And the laser pulse energy was ranged from 0.05 to 0.5 mJ/pulse by adjusting the laser output peak power from 0.25 to 2.5 W. a The OABR wave III peak amplitude showed a monotonic increase with the pulse energy increasing from 0.05 to 0.5 mJ/pulse. b The OABR wave III latency shortened along with the pulse energy increasing

Mentions: After the acoustic stimulation, pulsed SWIR laser stimulation with deafened animals was conducted in two steps. With all the experimental animals, the optically induced ABR signals were recorded stably and with high repeatability, and classical Jewett waveforms have been shown distinctly. In the first step, the laser pulse repetition rate was set at 11 Hz and the pulse width was kept 200 μs. The laser pulse energy was adjusted from 0.05 to 0.5 mJ/pulse by setting the laser output peak power from 0.25 to 2.5 W. Figure 4 showed the OABR waveforms evoked with varied pulse energy levels after the deafening procedure, the waveforms were similar to the ABR evoked by acoustic stimuli, the OABR intensity increased and its wave III latency time shortened with increasing pulse energy levels. I/O curves further demonstrated this trend in Fig. 5, the OABR wave III peak amplitude increased monotonically along with the laser energy level, the mean value was 0.34 μV at 0.05 mJ/pulse energy level and it increased to 2.03 μV at 0.5 mJ/pulse laser energy, shown in Fig. 5a. And Fig. 5b showed that the OABR wave III latency time was about 4.76 ms at 0.05 mJ/pulse laser energy, while this latency shortened to 3.24 ms when the energy level increased to 0.5 mJ/pulse. Individual data across the animals were also shown in Fig. 5, and the differences were not significant (ANOVA, P > 0.05).Fig. 4


Pulsed 980 nm short wavelength infrared neural stimulation in cochlea and laser parameter effects on auditory response characteristics.

Wang J, Lu J, Li C, Xu L, Li X, Tian L - Biomed Eng Online (2015)

I/O curves of OABR wave III amplitude and latency as a function of laser pulse energy. The individual data measured across animals (n = 4) are shown by the different dash lines, and the mean is shown by the solid diamond with the standard error. The laser repetition rate and pulse width were kept to 11 Hz and 200 μs. And the laser pulse energy was ranged from 0.05 to 0.5 mJ/pulse by adjusting the laser output peak power from 0.25 to 2.5 W. a The OABR wave III peak amplitude showed a monotonic increase with the pulse energy increasing from 0.05 to 0.5 mJ/pulse. b The OABR wave III latency shortened along with the pulse energy increasing
© Copyright Policy - OpenAccess
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC4597400&req=5

Fig5: I/O curves of OABR wave III amplitude and latency as a function of laser pulse energy. The individual data measured across animals (n = 4) are shown by the different dash lines, and the mean is shown by the solid diamond with the standard error. The laser repetition rate and pulse width were kept to 11 Hz and 200 μs. And the laser pulse energy was ranged from 0.05 to 0.5 mJ/pulse by adjusting the laser output peak power from 0.25 to 2.5 W. a The OABR wave III peak amplitude showed a monotonic increase with the pulse energy increasing from 0.05 to 0.5 mJ/pulse. b The OABR wave III latency shortened along with the pulse energy increasing
Mentions: After the acoustic stimulation, pulsed SWIR laser stimulation with deafened animals was conducted in two steps. With all the experimental animals, the optically induced ABR signals were recorded stably and with high repeatability, and classical Jewett waveforms have been shown distinctly. In the first step, the laser pulse repetition rate was set at 11 Hz and the pulse width was kept 200 μs. The laser pulse energy was adjusted from 0.05 to 0.5 mJ/pulse by setting the laser output peak power from 0.25 to 2.5 W. Figure 4 showed the OABR waveforms evoked with varied pulse energy levels after the deafening procedure, the waveforms were similar to the ABR evoked by acoustic stimuli, the OABR intensity increased and its wave III latency time shortened with increasing pulse energy levels. I/O curves further demonstrated this trend in Fig. 5, the OABR wave III peak amplitude increased monotonically along with the laser energy level, the mean value was 0.34 μV at 0.05 mJ/pulse energy level and it increased to 2.03 μV at 0.5 mJ/pulse laser energy, shown in Fig. 5a. And Fig. 5b showed that the OABR wave III latency time was about 4.76 ms at 0.05 mJ/pulse laser energy, while this latency shortened to 3.24 ms when the energy level increased to 0.5 mJ/pulse. Individual data across the animals were also shown in Fig. 5, and the differences were not significant (ANOVA, P > 0.05).Fig. 4

Bottom Line: The results showed that the optically evoked auditory brainstem response (OABR) had a similar waveform to the acoustically induced ABR with click sound stimulus.Our study suggests that 980 nm SWIR laser is an effective stimulus for auditory neurons activation in vivo.The evoked OABR amplitude and latency are highly affected by the laser pulse energy, while not sensitive to the pulse width variability in 100-800 μs range.

View Article: PubMed Central - PubMed

Affiliation: School of Information Science and Engineering, Shandong University, 250100, Jinan, Shandong, China. 373759703@qq.com.

ABSTRACT

Background: Auditory neural stimulation with pulsed infrared radiation has been proposed as an alternative method to activate the auditory nerves in vivo. Infrared wavelengths from 1800-2150 nm with high water absorption were mainly selected in previous studies. However, few researchers have used the short-wavelength infrared (SWIR) for auditory nerve stimulation and limited pulse parameters variability has been investigated so far.

Methods: In this paper, we pioneered to use the 980 nm SWIR laser with adjustable pulse parameter as a stimulus to act on the deafened guinea pigs' cochlea in vivo. Pulsed laser light was guided through the cochlear round window to irradiate the spiral ganglion cells via a 105 μm optical fiber, and then the laser pulse parameters variability and its influence to auditory response characteristics were studied.

Results: The results showed that the optically evoked auditory brainstem response (OABR) had a similar waveform to the acoustically induced ABR with click sound stimulus. And the evoked OABR amplitude had a positive correlation, while the OABR latency period showed a negative correlation, with the laser pulse energy increase. However, when holding the laser peak power constant, the pulse width variability ranged from 100 to 800 μs showed little influence on the evoked OABR amplitude and its latency period.

Conclusions: Our study suggests that 980 nm SWIR laser is an effective stimulus for auditory neurons activation in vivo. The evoked OABR amplitude and latency are highly affected by the laser pulse energy, while not sensitive to the pulse width variability in 100-800 μs range.

No MeSH data available.