Time course of organ of Corti degeneration after noise exposure

Publication date: Available online 24 November 2016
Source:Hearing Research
Author(s): Barbara A. Bohne, Melissa Kimlinger, Gary W. Harding
From our permanent collection of plastic-embedded flat preparations of chinchilla cochleae, 22 controls and 199 ears from noise-exposed animals were used to determine when, postexposure, hair cell (HC) and supporting cell (SC) degeneration were completed. The exposed ears were divided into four groups based on exposure parameters: 0.5- or 4-kHz octave band of noise at moderate (M) or high (H) intensities. Postexposure survival ranged from < 1 h to 2.5 y. Ears fixed ≤ 0-12 h postexposure were called ‛acute‛. For ‛chronic‛ ears, postexposure survival was ≥7 d for groups 0.5M and 4M, ≥ 1 mo for the 4H group and ≥ 7 mo for the 0.5H group. The time course of inner-ear degeneration after noise exposure was determined from data in the 0.5H and 4H groups because these groups contained ears with intermediate survival times. Outer hair cells (OHCs) began dying during the exposure. OHC loss slowed down beyond 1 mo but was still present. Conversely, much inner hair cell loss was delayed until 1-3 wk postexposure. Outer pillar and inner pillar losses were present at a low level in acute ears but increased exponentially thereafter. These results are the first to demonstrate quantitatively that hair cells (HCs) and supporting cells (SCs) may continue to degenerate for months postexposure.With short postexposure survivals, the remaining SCs often had pathological changes, including: buckled pillar bodies, shifted Deiters‛ cell (DC) nuclei, detachment of DCs from the basilar membrane and/or splitting of the reticular lamina. These pathological changes appeared to allow endolymph and perilymph to intermix in the fluid spaces of the organ of Corti, damaging additional HCs, SCs and nerve fibers. This mechanism may account for some postexposure degeneration. In ears exposed to moderate noise, some of these SC changes appeared to be reversible. In ears exposed to high-level noise, these changes appeared to indicate impending degeneration.



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Time course of organ of Corti degeneration after noise exposure

Publication date: Available online 24 November 2016
Source:Hearing Research
Author(s): Barbara A. Bohne, Melissa Kimlinger, Gary W. Harding
From our permanent collection of plastic-embedded flat preparations of chinchilla cochleae, 22 controls and 199 ears from noise-exposed animals were used to determine when, postexposure, hair cell (HC) and supporting cell (SC) degeneration were completed. The exposed ears were divided into four groups based on exposure parameters: 0.5- or 4-kHz octave band of noise at moderate (M) or high (H) intensities. Postexposure survival ranged from < 1 h to 2.5 y. Ears fixed ≤ 0-12 h postexposure were called ‛acute‛. For ‛chronic‛ ears, postexposure survival was ≥7 d for groups 0.5M and 4M, ≥ 1 mo for the 4H group and ≥ 7 mo for the 0.5H group. The time course of inner-ear degeneration after noise exposure was determined from data in the 0.5H and 4H groups because these groups contained ears with intermediate survival times. Outer hair cells (OHCs) began dying during the exposure. OHC loss slowed down beyond 1 mo but was still present. Conversely, much inner hair cell loss was delayed until 1-3 wk postexposure. Outer pillar and inner pillar losses were present at a low level in acute ears but increased exponentially thereafter. These results are the first to demonstrate quantitatively that hair cells (HCs) and supporting cells (SCs) may continue to degenerate for months postexposure.With short postexposure survivals, the remaining SCs often had pathological changes, including: buckled pillar bodies, shifted Deiters‛ cell (DC) nuclei, detachment of DCs from the basilar membrane and/or splitting of the reticular lamina. These pathological changes appeared to allow endolymph and perilymph to intermix in the fluid spaces of the organ of Corti, damaging additional HCs, SCs and nerve fibers. This mechanism may account for some postexposure degeneration. In ears exposed to moderate noise, some of these SC changes appeared to be reversible. In ears exposed to high-level noise, these changes appeared to indicate impending degeneration.



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Time course of organ of Corti degeneration after noise exposure

Publication date: Available online 24 November 2016
Source:Hearing Research
Author(s): Barbara A. Bohne, Melissa Kimlinger, Gary W. Harding
From our permanent collection of plastic-embedded flat preparations of chinchilla cochleae, 22 controls and 199 ears from noise-exposed animals were used to determine when, postexposure, hair cell (HC) and supporting cell (SC) degeneration were completed. The exposed ears were divided into four groups based on exposure parameters: 0.5- or 4-kHz octave band of noise at moderate (M) or high (H) intensities. Postexposure survival ranged from < 1 h to 2.5 y. Ears fixed ≤ 0-12 h postexposure were called ‛acute‛. For ‛chronic‛ ears, postexposure survival was ≥7 d for groups 0.5M and 4M, ≥ 1 mo for the 4H group and ≥ 7 mo for the 0.5H group. The time course of inner-ear degeneration after noise exposure was determined from data in the 0.5H and 4H groups because these groups contained ears with intermediate survival times. Outer hair cells (OHCs) began dying during the exposure. OHC loss slowed down beyond 1 mo but was still present. Conversely, much inner hair cell loss was delayed until 1-3 wk postexposure. Outer pillar and inner pillar losses were present at a low level in acute ears but increased exponentially thereafter. These results are the first to demonstrate quantitatively that hair cells (HCs) and supporting cells (SCs) may continue to degenerate for months postexposure.With short postexposure survivals, the remaining SCs often had pathological changes, including: buckled pillar bodies, shifted Deiters‛ cell (DC) nuclei, detachment of DCs from the basilar membrane and/or splitting of the reticular lamina. These pathological changes appeared to allow endolymph and perilymph to intermix in the fluid spaces of the organ of Corti, damaging additional HCs, SCs and nerve fibers. This mechanism may account for some postexposure degeneration. In ears exposed to moderate noise, some of these SC changes appeared to be reversible. In ears exposed to high-level noise, these changes appeared to indicate impending degeneration.



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Head movement measurement: An alternative method for posturography studies

Publication date: February 2017
Source:Gait & Posture, Volume 52
Author(s): L.F. Ciria, M.A. Muñoz, J. Gea, N. Peña, J.G.V. Miranda, P. Montoya, J. Vila
The present study evaluated the measurement of head movements as a valid method for postural emotional studies using the comparison of simultaneous recording of center of pressure (COP) sway as criterion. Thirty female students viewed a set of 12 pleasant, 12 unpleasant and 12 neutral pictures from the International Affective Picture System, repeated twice, using a block presentation procedure while standing on a force platform (AMTI AccuSway). Head movements were recorded using a webcam (©KPC139E) located in the ceiling in line with the force platform and a light-emitting diode (LED) placed on the top of the head. Open source software (CvMob 3.1) was used to process the data. High indices of correlation and coherence between head and COP sway were observed. In addition, pleasant pictures, compared with unpleasant pictures, elicited greater body sway in the anterior-posterior axis, suggesting an approach response to appetitive stimuli. Thus, the measurement of head movement can be an alternative or complementary method to recording COP for studying human postural changes.



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Whole body organization during a symmetric bimanual pick up task in overweight and obese children

Publication date: February 2017
Source:Gait & Posture, Volume 52
Author(s): Ya-Ching Hung, Melissa Mangiafreno, Simone V. Gill
Information on the effects of obesity on the biomechanics of whole body movement control in children is limited. The purpose of the current study is to test the hypothesis that during a simple pick up task, overweight and obese children will organize their whole body movements differently than those in normal weight children. Twelve children who were overweight or obese (5–13 years old) and twelve age matched normal weight children participated in the study. Children picked up an empty box to waist height at a self-selected pace while kinematic and kinetic data were recorded and analyzed using a VICON system and two AMTI force plates. The overweight and obese group showed less knee flexion in both legs, more spine flexion, and less excursion in the height of their center of mass (all Ps<0.05). However, the overweight and obese group had more anterior movement in their center of mass (P<0.05). For the center of pressure findings, the overweight and obese group had greater anterior excursion with faster average anterior moving speed and spent a longer time with the center of pressure reached forward (all Ps<0.05). These findings indicate that overweight and obese children organize their whole body movement during a simple pick up task differently with higher and more forward center of mass, quickly shifting their center of pressure anteriorly, and with a longer period of time with the center of pressure remaining forward. Their movement strategy may put them in a less stable condition and thus make them prone to losing balance.



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Automatic identification of gait events during walking on uneven surfaces

Publication date: February 2017
Source:Gait & Posture, Volume 52
Author(s): Nils Eckardt, Armin Kibele
The accurate detection of gait events is essential for clinical gait analysis. Aside from speed, surface characteristics like planarity and compliance can affect gait kinematics. Therefore detection of kinematic gait events on uneven surfaces may be inaccurate. To date, no study has investigated the possible influence of surface characteristics on gait event detection. Thus, the purpose of this study was to assess and compare the performance of four kinematic-based gait event detection algorithms (horizontal heel-heel displacement, foot velocity, heel/toe-PSIS displacement, peak hip extension) during walking on three surfaces with different degrees of planarity. Kinematic and force plate data were collected on thirteen athletes during two self-selected walking speeds at a normal (1.30±0.03m/s) and fast pace (1.70±0.10m/s). Footstrike and toe-off events were calculated by the algorithms and compared to vertical ground reaction force as a reference. The main findings of the study were: (1) surface configuration had an effect on algorithm accuracy (p<0.010, 0.84<d<2.79); (2) the vertical foot-velocity profile provided the lowest RMSE for footstrike (8.8–14.6ms) during normal walking and toe-off (15.4–24.9ms) during normal and fast walking on all surfaces; (3) horizontal heel-ankle displacement provided the lowest RMSE for footstrike during fast walking on all surfaces (RMSE: 8.9–13.8ms). Overall, the vertical foot-velocity algorithm provided low RMSE for all conditions, is easy to apply and thus recommended for gait event detection.



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Head movement measurement: An alternative method for posturography studies

Publication date: February 2017
Source:Gait & Posture, Volume 52
Author(s): L.F. Ciria, M.A. Muñoz, J. Gea, N. Peña, J.G.V. Miranda, P. Montoya, J. Vila
The present study evaluated the measurement of head movements as a valid method for postural emotional studies using the comparison of simultaneous recording of center of pressure (COP) sway as criterion. Thirty female students viewed a set of 12 pleasant, 12 unpleasant and 12 neutral pictures from the International Affective Picture System, repeated twice, using a block presentation procedure while standing on a force platform (AMTI AccuSway). Head movements were recorded using a webcam (©KPC139E) located in the ceiling in line with the force platform and a light-emitting diode (LED) placed on the top of the head. Open source software (CvMob 3.1) was used to process the data. High indices of correlation and coherence between head and COP sway were observed. In addition, pleasant pictures, compared with unpleasant pictures, elicited greater body sway in the anterior-posterior axis, suggesting an approach response to appetitive stimuli. Thus, the measurement of head movement can be an alternative or complementary method to recording COP for studying human postural changes.



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Whole body organization during a symmetric bimanual pick up task in overweight and obese children

Publication date: February 2017
Source:Gait & Posture, Volume 52
Author(s): Ya-Ching Hung, Melissa Mangiafreno, Simone V. Gill
Information on the effects of obesity on the biomechanics of whole body movement control in children is limited. The purpose of the current study is to test the hypothesis that during a simple pick up task, overweight and obese children will organize their whole body movements differently than those in normal weight children. Twelve children who were overweight or obese (5–13 years old) and twelve age matched normal weight children participated in the study. Children picked up an empty box to waist height at a self-selected pace while kinematic and kinetic data were recorded and analyzed using a VICON system and two AMTI force plates. The overweight and obese group showed less knee flexion in both legs, more spine flexion, and less excursion in the height of their center of mass (all Ps<0.05). However, the overweight and obese group had more anterior movement in their center of mass (P<0.05). For the center of pressure findings, the overweight and obese group had greater anterior excursion with faster average anterior moving speed and spent a longer time with the center of pressure reached forward (all Ps<0.05). These findings indicate that overweight and obese children organize their whole body movement during a simple pick up task differently with higher and more forward center of mass, quickly shifting their center of pressure anteriorly, and with a longer period of time with the center of pressure remaining forward. Their movement strategy may put them in a less stable condition and thus make them prone to losing balance.



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Automatic identification of gait events during walking on uneven surfaces

Publication date: February 2017
Source:Gait & Posture, Volume 52
Author(s): Nils Eckardt, Armin Kibele
The accurate detection of gait events is essential for clinical gait analysis. Aside from speed, surface characteristics like planarity and compliance can affect gait kinematics. Therefore detection of kinematic gait events on uneven surfaces may be inaccurate. To date, no study has investigated the possible influence of surface characteristics on gait event detection. Thus, the purpose of this study was to assess and compare the performance of four kinematic-based gait event detection algorithms (horizontal heel-heel displacement, foot velocity, heel/toe-PSIS displacement, peak hip extension) during walking on three surfaces with different degrees of planarity. Kinematic and force plate data were collected on thirteen athletes during two self-selected walking speeds at a normal (1.30±0.03m/s) and fast pace (1.70±0.10m/s). Footstrike and toe-off events were calculated by the algorithms and compared to vertical ground reaction force as a reference. The main findings of the study were: (1) surface configuration had an effect on algorithm accuracy (p<0.010, 0.84<d<2.79); (2) the vertical foot-velocity profile provided the lowest RMSE for footstrike (8.8–14.6ms) during normal walking and toe-off (15.4–24.9ms) during normal and fast walking on all surfaces; (3) horizontal heel-ankle displacement provided the lowest RMSE for footstrike during fast walking on all surfaces (RMSE: 8.9–13.8ms). Overall, the vertical foot-velocity algorithm provided low RMSE for all conditions, is easy to apply and thus recommended for gait event detection.



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Head movement measurement: An alternative method for posturography studies

Publication date: February 2017
Source:Gait & Posture, Volume 52
Author(s): L.F. Ciria, M.A. Muñoz, J. Gea, N. Peña, J.G.V. Miranda, P. Montoya, J. Vila
The present study evaluated the measurement of head movements as a valid method for postural emotional studies using the comparison of simultaneous recording of center of pressure (COP) sway as criterion. Thirty female students viewed a set of 12 pleasant, 12 unpleasant and 12 neutral pictures from the International Affective Picture System, repeated twice, using a block presentation procedure while standing on a force platform (AMTI AccuSway). Head movements were recorded using a webcam (©KPC139E) located in the ceiling in line with the force platform and a light-emitting diode (LED) placed on the top of the head. Open source software (CvMob 3.1) was used to process the data. High indices of correlation and coherence between head and COP sway were observed. In addition, pleasant pictures, compared with unpleasant pictures, elicited greater body sway in the anterior-posterior axis, suggesting an approach response to appetitive stimuli. Thus, the measurement of head movement can be an alternative or complementary method to recording COP for studying human postural changes.



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Whole body organization during a symmetric bimanual pick up task in overweight and obese children

Publication date: February 2017
Source:Gait & Posture, Volume 52
Author(s): Ya-Ching Hung, Melissa Mangiafreno, Simone V. Gill
Information on the effects of obesity on the biomechanics of whole body movement control in children is limited. The purpose of the current study is to test the hypothesis that during a simple pick up task, overweight and obese children will organize their whole body movements differently than those in normal weight children. Twelve children who were overweight or obese (5–13 years old) and twelve age matched normal weight children participated in the study. Children picked up an empty box to waist height at a self-selected pace while kinematic and kinetic data were recorded and analyzed using a VICON system and two AMTI force plates. The overweight and obese group showed less knee flexion in both legs, more spine flexion, and less excursion in the height of their center of mass (all Ps<0.05). However, the overweight and obese group had more anterior movement in their center of mass (P<0.05). For the center of pressure findings, the overweight and obese group had greater anterior excursion with faster average anterior moving speed and spent a longer time with the center of pressure reached forward (all Ps<0.05). These findings indicate that overweight and obese children organize their whole body movement during a simple pick up task differently with higher and more forward center of mass, quickly shifting their center of pressure anteriorly, and with a longer period of time with the center of pressure remaining forward. Their movement strategy may put them in a less stable condition and thus make them prone to losing balance.



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Automatic identification of gait events during walking on uneven surfaces

Publication date: February 2017
Source:Gait & Posture, Volume 52
Author(s): Nils Eckardt, Armin Kibele
The accurate detection of gait events is essential for clinical gait analysis. Aside from speed, surface characteristics like planarity and compliance can affect gait kinematics. Therefore detection of kinematic gait events on uneven surfaces may be inaccurate. To date, no study has investigated the possible influence of surface characteristics on gait event detection. Thus, the purpose of this study was to assess and compare the performance of four kinematic-based gait event detection algorithms (horizontal heel-heel displacement, foot velocity, heel/toe-PSIS displacement, peak hip extension) during walking on three surfaces with different degrees of planarity. Kinematic and force plate data were collected on thirteen athletes during two self-selected walking speeds at a normal (1.30±0.03m/s) and fast pace (1.70±0.10m/s). Footstrike and toe-off events were calculated by the algorithms and compared to vertical ground reaction force as a reference. The main findings of the study were: (1) surface configuration had an effect on algorithm accuracy (p<0.010, 0.84<d<2.79); (2) the vertical foot-velocity profile provided the lowest RMSE for footstrike (8.8–14.6ms) during normal walking and toe-off (15.4–24.9ms) during normal and fast walking on all surfaces; (3) horizontal heel-ankle displacement provided the lowest RMSE for footstrike during fast walking on all surfaces (RMSE: 8.9–13.8ms). Overall, the vertical foot-velocity algorithm provided low RMSE for all conditions, is easy to apply and thus recommended for gait event detection.



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Variable expressivity and genetic heterogeneity involving DPT and SEMA3D genes in autosomal dominant familial Meniere's disease.

Variable expressivity and genetic heterogeneity involving DPT and SEMA3D genes in autosomal dominant familial Meniere's disease.

Eur J Hum Genet. 2016 Nov 23;:

Authors: Martín-Sierra C, Gallego-Martinez A, Requena T, Frejo L, Batuecas-Caletrío A, Lopez-Escamez JA

Abstract
Autosomal dominant (AD) familial Meniere's disease (FMD) is a rare disorder involving the inner ear defined by sensorineural hearing loss, tinnitus and episodic vertigo. Here, we have identified two novel and rare heterozygous variants in the SEMA3D and DPT genes segregating with the complete phenotype that have variable expressivity in two pedigrees with AD-FMD. A detailed characterization of the phenotype within each family illustrates the clinical heterogeneity in the onset and progression of the disease. We also showed the expression of both genes in the human cochlea and performed in silico analyses of these variants. Three-dimensional protein modelling showed changes in the structure of the protein indicating potential physical interactions. These results confirm a genetic heterogeneity in FMD with incomplete penetrance and variable expressivity.European Journal of Human Genetics advance online publication, 23 November 2016; doi:10.1038/ejhg.2016.154.

PMID: 27876815 [PubMed - as supplied by publisher]

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