Intracochlear near infrared stimulation: Feasibility of optoacoustic stimulation in vivo

Publication date: Available online 12 November 2018

Source: Hearing Research

Author(s): Peter Baumhoff, Nicole Kallweit, Andrej Kral

Abstract

Intracochlear optical stimulation has been suggested as an alternative approach to hearing prosthetics in recent years. This study investigated the properties of a near infrared laser (NIR) induced optoacoustic effect. Pressure recordings were performed at the external meatus of anaesthetized guinea pigs during intracochlear NIR stimulation. The sound pressure and power spectra were determined. The results were compared to multi unit responses in the inferior colliculus (IC). Additionally, the responses to NIR stimulation were compared to IC responses induced by intracochlear electric stimulation at the same cochlear position to investigate a potentially confounding contribution of direct neural NIR stimulation. The power spectra of the sound recorded at the external meatus (n=7) had most power at frequencies below 10 kHz and showed little variation for different stimulation sites. The mean spike rates of IC units responding to intracochlear NIR stimulation (n=222) of 17 animals were significantly correlated with the power of the externally recorded signal at frequencies corresponding to the best frequencies of the IC units. The response strength as well as the sound pressure at the external meatus depended on the pulse peak power of the optical stimulus. The sound pressure recorded at the external meatus reached levels above 70 dB SPL peak equivalent. In hearing animals a cochlear activation apical to the cochlear location of the fiber was found. The absence of any NIR responses after pharmacologically deafening and the comparison to electric stimulation at the NIR stimulation revealed no indication of a confounding direct neural NIR stimulation. Intracochlear optoacoustic stimulation might become useful in combined electro-acoustic stimulation devices in the future.

Graphical abstract

from #Audiology via ola Kala on Inoreader https://ift.tt/2DfY9Cs
via IFTTT

Intracochlear near infrared stimulation: Feasibility of optoacoustic stimulation in vivo

Publication date: Available online 12 November 2018

Source: Hearing Research

Author(s): Peter Baumhoff, Nicole Kallweit, Andrej Kral

Abstract

Intracochlear optical stimulation has been suggested as an alternative approach to hearing prosthetics in recent years. This study investigated the properties of a near infrared laser (NIR) induced optoacoustic effect. Pressure recordings were performed at the external meatus of anaesthetized guinea pigs during intracochlear NIR stimulation. The sound pressure and power spectra were determined. The results were compared to multi unit responses in the inferior colliculus (IC). Additionally, the responses to NIR stimulation were compared to IC responses induced by intracochlear electric stimulation at the same cochlear position to investigate a potentially confounding contribution of direct neural NIR stimulation. The power spectra of the sound recorded at the external meatus (n=7) had most power at frequencies below 10 kHz and showed little variation for different stimulation sites. The mean spike rates of IC units responding to intracochlear NIR stimulation (n=222) of 17 animals were significantly correlated with the power of the externally recorded signal at frequencies corresponding to the best frequencies of the IC units. The response strength as well as the sound pressure at the external meatus depended on the pulse peak power of the optical stimulus. The sound pressure recorded at the external meatus reached levels above 70 dB SPL peak equivalent. In hearing animals a cochlear activation apical to the cochlear location of the fiber was found. The absence of any NIR responses after pharmacologically deafening and the comparison to electric stimulation at the NIR stimulation revealed no indication of a confounding direct neural NIR stimulation. Intracochlear optoacoustic stimulation might become useful in combined electro-acoustic stimulation devices in the future.

Graphical abstract

from #Audiology via ola Kala on Inoreader https://ift.tt/2DfY9Cs
via IFTTT

Intracochlear near infrared stimulation: Feasibility of optoacoustic stimulation in vivo

Publication date: Available online 12 November 2018

Source: Hearing Research

Author(s): Peter Baumhoff, Nicole Kallweit, Andrej Kral

Abstract

Intracochlear optical stimulation has been suggested as an alternative approach to hearing prosthetics in recent years. This study investigated the properties of a near infrared laser (NIR) induced optoacoustic effect. Pressure recordings were performed at the external meatus of anaesthetized guinea pigs during intracochlear NIR stimulation. The sound pressure and power spectra were determined. The results were compared to multi unit responses in the inferior colliculus (IC). Additionally, the responses to NIR stimulation were compared to IC responses induced by intracochlear electric stimulation at the same cochlear position to investigate a potentially confounding contribution of direct neural NIR stimulation. The power spectra of the sound recorded at the external meatus (n=7) had most power at frequencies below 10 kHz and showed little variation for different stimulation sites. The mean spike rates of IC units responding to intracochlear NIR stimulation (n=222) of 17 animals were significantly correlated with the power of the externally recorded signal at frequencies corresponding to the best frequencies of the IC units. The response strength as well as the sound pressure at the external meatus depended on the pulse peak power of the optical stimulus. The sound pressure recorded at the external meatus reached levels above 70 dB SPL peak equivalent. In hearing animals a cochlear activation apical to the cochlear location of the fiber was found. The absence of any NIR responses after pharmacologically deafening and the comparison to electric stimulation at the NIR stimulation revealed no indication of a confounding direct neural NIR stimulation. Intracochlear optoacoustic stimulation might become useful in combined electro-acoustic stimulation devices in the future.

Graphical abstract

from #Audiology via ola Kala on Inoreader https://ift.tt/2DfY9Cs
via IFTTT

Intracochlear near infrared stimulation: Feasibility of optoacoustic stimulation in vivo

Publication date: Available online 12 November 2018

Source: Hearing Research

Author(s): Peter Baumhoff, Nicole Kallweit, Andrej Kral

Abstract

Intracochlear optical stimulation has been suggested as an alternative approach to hearing prosthetics in recent years. This study investigated the properties of a near infrared laser (NIR) induced optoacoustic effect. Pressure recordings were performed at the external meatus of anaesthetized guinea pigs during intracochlear NIR stimulation. The sound pressure and power spectra were determined. The results were compared to multi unit responses in the inferior colliculus (IC). Additionally, the responses to NIR stimulation were compared to IC responses induced by intracochlear electric stimulation at the same cochlear position to investigate a potentially confounding contribution of direct neural NIR stimulation. The power spectra of the sound recorded at the external meatus (n=7) had most power at frequencies below 10 kHz and showed little variation for different stimulation sites. The mean spike rates of IC units responding to intracochlear NIR stimulation (n=222) of 17 animals were significantly correlated with the power of the externally recorded signal at frequencies corresponding to the best frequencies of the IC units. The response strength as well as the sound pressure at the external meatus depended on the pulse peak power of the optical stimulus. The sound pressure recorded at the external meatus reached levels above 70 dB SPL peak equivalent. In hearing animals a cochlear activation apical to the cochlear location of the fiber was found. The absence of any NIR responses after pharmacologically deafening and the comparison to electric stimulation at the NIR stimulation revealed no indication of a confounding direct neural NIR stimulation. Intracochlear optoacoustic stimulation might become useful in combined electro-acoustic stimulation devices in the future.

Graphical abstract

from #Audiology via ola Kala on Inoreader https://ift.tt/2DfY9Cs
via IFTTT

The Effects of Downhill Slope on Kinematics and Kinetics of the Lower Extremity Joints During Running

Publication date: Available online 12 November 2018

Source: Gait & Posture

Author(s): Sang-Kyoon Park, Hyun-Min Jeon, Wing-Kai Lam, Darren Stefanyshyn, Jiseon Ryu

ABSTRACT

Background

The purpose of this study was to investigate how lower extremity kinematics and kinetics change when running downhill.

Methods

Fifteen male recreational runners ran on an instrumented treadmill with three different slope conditions [level (0º), moderate (-6º), and steep (-9º)] at a controlled speed of 3.2 m/s. Ten consecutive steps were selected for analysis for each of the slope conditions and the order of slope conditions was randomized. Synchonized motion analysis and force plate was used to determine joint kinematics and kinetics.

Results

Compared to level running, participants demonstrated significantly larger knee flexion and smaller ankle plantar-flexion and hip flexion during downhill running (Ps < 0.05). Significantly smaller peak propulsive ground reaction forces and posterior impulses were found during downhill running (Ps < 0.05). Furthermore, participants experienced significantly larger extension moment and negative joint power at the knee (Ps < 0.05) but smaller plantar-flexion moment and negative joint power at the ankle during downhill running (Ps < 0.05). Negative net joint work increased for all joints with increased declinations and the knee joint showed the greatest increase in negative net joint work amongst the three joints (Ps < 0.05).

Significance

These findings indicate that runners modify their running mechanics resulting in greater kinetic demand on the knee during downhill running. Differences in lower extremity injury mechanisms with different running slopes may be linked to the changes in loading at the knee but further investigation using clinical trials is needed to support the potential relationship.

from #Audiology via ola Kala on Inoreader https://ift.tt/2T9Wcx9
via IFTTT

How does the slope gradient affect spatiotemporal parameters during running? Influence of athletic level and vertical and leg stiffness

Publication date: Available online 11 November 2018

Source: Gait & Posture

Author(s): Felipe García-Pinillos, Pedro Á. Latorre-Román, Rodrigo Ramírez-Campillo, Juan A. Párraga-Montilla, Luis E. Roche-Seruendo

Abstract

Background

The current evidence leaves certain questions unanswered, including whether well-trained athletes adapt to different slope gradients in the same way as amateurs, and whether stiffness influences spatiotemporal adaptations during uphill running.

Research question

This study aimed to determine the effect of different slope gradients (0%–11%) on spatiotemporal gait characteristics during running, taking into account the influence of athletic level, vertical and leg stiffness.

Methods

Male endurance runners (12 amateurs, 10 highly-trained) performed a running test on a motorized treadmill. The running velocity was set at 12 km/h, and participants completed six different running conditions (0, 3, 5, 7, 9 and 11% gradients). Spatiotemporal parameters were measured using the OptoGait system. Vertical (Kvert) and leg (Kleg) stiffness were calculated according to the sine-wave method.

Results

A 2 (amateur; highly-trained) x 6 (running conditions) ANOVA found no significant between-group differences in spatiotemporal parameters at any gradient (P ≥ 0.05); however, significant Kvert and Kleg differences (P < 0.05) were found within both groups with increasing gradients. Stepwise linear regression analysis showed that Kleg was strongly associated with contact time (R²  = 0.797, P < 0.001), whereas Kvert was associated with spatiotemporal adaptations to different slope gradients (R²  = 0.547, P = 0.002).

Significance

An increased slope gradient (0-11%) at a given running velocity (12 km.h^-1) caused spatiotemporal adaptations (i.e., increased CT and SF and decreased FT, SL and SA) regardless of the athletic level of the runner, although a non-significant trend differentiated the adaptations between the amateur and highly-trained groups. The results also indicated that leg stiffness plays a key role in the characteristics of spatiotemporal gait during level running, whereas vertical stiffness is strongly associated with spatiotemporal adaptations when running uphill.

from #Audiology via ola Kala on Inoreader https://ift.tt/2zNGteh
via IFTTT

Visual feedback gait re-training in overweight children can reduce excessive tibial acceleration during walking and running: an experimental intervention study

Publication date: Available online 11 November 2018

Source: Gait & Posture

Author(s): Oren Tirosh, Nili Steinberg, Dan Nemet, Alon Eliakim, Guy Orland

Abstract

Background

Being overweight may increase the risk for developing stress fracture, as overweight adults and children were reported to have greater pressure peaks and rates under the heel during walking when compared with their normal-weight counterparts. Biofeedback gait retraining was shown to reduce ground impact magnitude in adults but not yet in children.

Research question

The study examined whether overweight children have greater tibia peak positive acceleration (PPA) at ground impact during fast walking and running compared to healthy weight children, and whether visual feedback gait retraining program can be used to reduce PPA in overweight children.

Methods

Twenty five overweight and 12 healthy weight children participated in the study. Overweight children were randomly assigned into either feedback group or control no-feedback group of 8 sessions training program over 2-weeks. Tibia PPA at ground impact output from a wearable inertial sensor attached to the tibia was the feedback displayed on a monitor placed in front of the treadmill during walking and running.

Results

Compared to healthy weight children, overweight participants showed significant greater PPA values in running (p < 0.05), but not in fast walking. Feedback group significantly reduced PPA by 16% (p < 0.01), and these changes persisted at the 1-month follow-up.

Significance

Tibia PPA may be used in evaluating overweight children as a risk assessment to potential injuries due to high ground impact during running. Gait retraining using real-time feedback of tibia PPA may be useful in rehabilitation programs to reduce ground impact in overweight children.

from #Audiology via ola Kala on Inoreader https://ift.tt/2T62GNo
via IFTTT

The Effects of Downhill Slope on Kinematics and Kinetics of the Lower Extremity Joints During Running

Publication date: Available online 12 November 2018

Source: Gait & Posture

Author(s): Sang-Kyoon Park, Hyun-Min Jeon, Wing-Kai Lam, Darren Stefanyshyn, Jiseon Ryu

ABSTRACT

Background

The purpose of this study was to investigate how lower extremity kinematics and kinetics change when running downhill.

Methods

Fifteen male recreational runners ran on an instrumented treadmill with three different slope conditions [level (0º), moderate (-6º), and steep (-9º)] at a controlled speed of 3.2 m/s. Ten consecutive steps were selected for analysis for each of the slope conditions and the order of slope conditions was randomized. Synchonized motion analysis and force plate was used to determine joint kinematics and kinetics.

Results

Compared to level running, participants demonstrated significantly larger knee flexion and smaller ankle plantar-flexion and hip flexion during downhill running (Ps < 0.05). Significantly smaller peak propulsive ground reaction forces and posterior impulses were found during downhill running (Ps < 0.05). Furthermore, participants experienced significantly larger extension moment and negative joint power at the knee (Ps < 0.05) but smaller plantar-flexion moment and negative joint power at the ankle during downhill running (Ps < 0.05). Negative net joint work increased for all joints with increased declinations and the knee joint showed the greatest increase in negative net joint work amongst the three joints (Ps < 0.05).

Significance

These findings indicate that runners modify their running mechanics resulting in greater kinetic demand on the knee during downhill running. Differences in lower extremity injury mechanisms with different running slopes may be linked to the changes in loading at the knee but further investigation using clinical trials is needed to support the potential relationship.

from #Audiology via ola Kala on Inoreader https://ift.tt/2T9Wcx9
via IFTTT

How does the slope gradient affect spatiotemporal parameters during running? Influence of athletic level and vertical and leg stiffness

Publication date: Available online 11 November 2018

Source: Gait & Posture

Author(s): Felipe García-Pinillos, Pedro Á. Latorre-Román, Rodrigo Ramírez-Campillo, Juan A. Párraga-Montilla, Luis E. Roche-Seruendo

Abstract

Background

The current evidence leaves certain questions unanswered, including whether well-trained athletes adapt to different slope gradients in the same way as amateurs, and whether stiffness influences spatiotemporal adaptations during uphill running.

Research question

This study aimed to determine the effect of different slope gradients (0%–11%) on spatiotemporal gait characteristics during running, taking into account the influence of athletic level, vertical and leg stiffness.

Methods

Male endurance runners (12 amateurs, 10 highly-trained) performed a running test on a motorized treadmill. The running velocity was set at 12 km/h, and participants completed six different running conditions (0, 3, 5, 7, 9 and 11% gradients). Spatiotemporal parameters were measured using the OptoGait system. Vertical (Kvert) and leg (Kleg) stiffness were calculated according to the sine-wave method.

Results

A 2 (amateur; highly-trained) x 6 (running conditions) ANOVA found no significant between-group differences in spatiotemporal parameters at any gradient (P ≥ 0.05); however, significant Kvert and Kleg differences (P < 0.05) were found within both groups with increasing gradients. Stepwise linear regression analysis showed that Kleg was strongly associated with contact time (R²  = 0.797, P < 0.001), whereas Kvert was associated with spatiotemporal adaptations to different slope gradients (R²  = 0.547, P = 0.002).

Significance

An increased slope gradient (0-11%) at a given running velocity (12 km.h^-1) caused spatiotemporal adaptations (i.e., increased CT and SF and decreased FT, SL and SA) regardless of the athletic level of the runner, although a non-significant trend differentiated the adaptations between the amateur and highly-trained groups. The results also indicated that leg stiffness plays a key role in the characteristics of spatiotemporal gait during level running, whereas vertical stiffness is strongly associated with spatiotemporal adaptations when running uphill.

from #Audiology via ola Kala on Inoreader https://ift.tt/2zNGteh
via IFTTT

Visual feedback gait re-training in overweight children can reduce excessive tibial acceleration during walking and running: an experimental intervention study

Publication date: Available online 11 November 2018

Source: Gait & Posture

Author(s): Oren Tirosh, Nili Steinberg, Dan Nemet, Alon Eliakim, Guy Orland

Abstract

Background

Being overweight may increase the risk for developing stress fracture, as overweight adults and children were reported to have greater pressure peaks and rates under the heel during walking when compared with their normal-weight counterparts. Biofeedback gait retraining was shown to reduce ground impact magnitude in adults but not yet in children.

Research question

The study examined whether overweight children have greater tibia peak positive acceleration (PPA) at ground impact during fast walking and running compared to healthy weight children, and whether visual feedback gait retraining program can be used to reduce PPA in overweight children.

Methods

Twenty five overweight and 12 healthy weight children participated in the study. Overweight children were randomly assigned into either feedback group or control no-feedback group of 8 sessions training program over 2-weeks. Tibia PPA at ground impact output from a wearable inertial sensor attached to the tibia was the feedback displayed on a monitor placed in front of the treadmill during walking and running.

Results

Compared to healthy weight children, overweight participants showed significant greater PPA values in running (p < 0.05), but not in fast walking. Feedback group significantly reduced PPA by 16% (p < 0.01), and these changes persisted at the 1-month follow-up.

Significance

Tibia PPA may be used in evaluating overweight children as a risk assessment to potential injuries due to high ground impact during running. Gait retraining using real-time feedback of tibia PPA may be useful in rehabilitation programs to reduce ground impact in overweight children.

from #Audiology via ola Kala on Inoreader https://ift.tt/2T62GNo
via IFTTT