Limits...
Neurovestibular Compensation following Ototoxic Lesion and Labyrinthectomy.

Yazdanshenas H, Ashouri A, Kaufman G - Int Arch Otorhinolaryngol (2016)

Bottom Line: Results The gentamicin lesion resulted in a quicker recovery.Both groups displayed adaptation to the lesion by day 21, but long-term compensation did not completely revert to the original pre-lesion state.Static and dynamic compensations do not appear to be as independent as previous studies have suggested.

View Article: PubMed Central - PubMed

Affiliation: College of Medicine, UCLA & Charles R. Drew University of Medicine and Science, Los Angeles, CA, United States.

ABSTRACT
Introduction Unilateral labyrinthectomy and intra-tympanic gentamycin have been employed in the treatment of Ménière's disease, but the efficacy of these techniques has not been well established. Objective The objective of this study is to measure the time course of recovery from a unilateral labyrinthectomy either after ipsilateral topical treatment with gentamicin to the inner ear or without the previous insult. Methods Twenty-nine adult Mongolian gerbils were randomized into two experimental groups. Group 1 (n = 17) received a right ear gentamicin drug-induced lesion by unilateral labyrinthectomy (UL). Group 2 (n = 12) only received a right unilateral labyrinthectomy lesion. We measured the horizontal vestibulo-ocular responses in gerbils before and after the lesion. The gerbils received an angular acceleration stimulus and their eye movements were recorded. Results The gentamicin lesion resulted in a quicker recovery. Experimental groups underwent a similar time course of recovery. Statistical analysis showed no significant difference between the two groups. Both groups displayed adaptation to the lesion by day 21, but long-term compensation did not completely revert to the original pre-lesion state. Conclusions In a lesion requiring both static and dynamic compensation as in UL, the need for a static compensation may alter pre-existing compensation from a previous dynamic insult and require a new compensation. A previous lesion and adaptation is not preserved for a second lesion and the subject has to re-compensate. Therefore, surgical treatment in Meniere's disease such as UL can be considered without prior gentamicin treatment. Static and dynamic compensations do not appear to be as independent as previous studies have suggested.

No MeSH data available.


Related in: MedlinePlus

Centrifuge schematic composed of: the main earth vertical rotor, the eccentric earth vertical rotor, a pitch or roll platform of 30° where the animal and the camera are located, and a horizontal optokinetic drum.
© Copyright Policy
Related In: Results  -  Collection


getmorefigures.php?uid=PMC4835328&req=5

FI0371or-1: Centrifuge schematic composed of: the main earth vertical rotor, the eccentric earth vertical rotor, a pitch or roll platform of 30° where the animal and the camera are located, and a horizontal optokinetic drum.

Mentions: The apparatus used for these experiments has been previously described in detail by Kaufman (Fig. 1).16 It is a platform in a light-tight drum mounted on a yaw motor with the gerbil's head placed at the center of the axis of rotation. The eye position and movements were recorded by infrared VOG and the signals were processed using an ISCAN system (RK-426). Two 50 mm lenses (1:1.8, V5018) and monochrome cameras (model 20A6981, Videology Imaging Solutions) were located lateral to the gerbil on a turntable and an image of the eye was reflected on an infrared dichroic mirror. This helped the pupils to be observed while preserving the gerbil's field of view. Pupil movements were tracked using a pupil light sink method and two television monitors captured the left and right eye images from the ISCAN cameras. The researcher then recorded VOR in infrared light, with a wavelength of 920 nm, produced by infrared diodes placed in front of the camera lens on the optic axis of the measured eye. Since infrared is not in the gerbil's visible spectrum, the field of vision appears dark to the gerbil. Topical pilocarpine was used, when necessary, to constrict the animal's pupil, facilitating the eye movement recording. Eye rotation was measured using the geometric relationship of eye radius to the two dimensional translation detected by the camera. A small wide-edge camera provided a view of the gerbil, which was displayed on a small television monitor.


Neurovestibular Compensation following Ototoxic Lesion and Labyrinthectomy.

Yazdanshenas H, Ashouri A, Kaufman G - Int Arch Otorhinolaryngol (2016)

Centrifuge schematic composed of: the main earth vertical rotor, the eccentric earth vertical rotor, a pitch or roll platform of 30° where the animal and the camera are located, and a horizontal optokinetic drum.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC4835328&req=5

FI0371or-1: Centrifuge schematic composed of: the main earth vertical rotor, the eccentric earth vertical rotor, a pitch or roll platform of 30° where the animal and the camera are located, and a horizontal optokinetic drum.
Mentions: The apparatus used for these experiments has been previously described in detail by Kaufman (Fig. 1).16 It is a platform in a light-tight drum mounted on a yaw motor with the gerbil's head placed at the center of the axis of rotation. The eye position and movements were recorded by infrared VOG and the signals were processed using an ISCAN system (RK-426). Two 50 mm lenses (1:1.8, V5018) and monochrome cameras (model 20A6981, Videology Imaging Solutions) were located lateral to the gerbil on a turntable and an image of the eye was reflected on an infrared dichroic mirror. This helped the pupils to be observed while preserving the gerbil's field of view. Pupil movements were tracked using a pupil light sink method and two television monitors captured the left and right eye images from the ISCAN cameras. The researcher then recorded VOR in infrared light, with a wavelength of 920 nm, produced by infrared diodes placed in front of the camera lens on the optic axis of the measured eye. Since infrared is not in the gerbil's visible spectrum, the field of vision appears dark to the gerbil. Topical pilocarpine was used, when necessary, to constrict the animal's pupil, facilitating the eye movement recording. Eye rotation was measured using the geometric relationship of eye radius to the two dimensional translation detected by the camera. A small wide-edge camera provided a view of the gerbil, which was displayed on a small television monitor.

Bottom Line: Results The gentamicin lesion resulted in a quicker recovery.Both groups displayed adaptation to the lesion by day 21, but long-term compensation did not completely revert to the original pre-lesion state.Static and dynamic compensations do not appear to be as independent as previous studies have suggested.

View Article: PubMed Central - PubMed

Affiliation: College of Medicine, UCLA & Charles R. Drew University of Medicine and Science, Los Angeles, CA, United States.

ABSTRACT
Introduction Unilateral labyrinthectomy and intra-tympanic gentamycin have been employed in the treatment of Ménière's disease, but the efficacy of these techniques has not been well established. Objective The objective of this study is to measure the time course of recovery from a unilateral labyrinthectomy either after ipsilateral topical treatment with gentamicin to the inner ear or without the previous insult. Methods Twenty-nine adult Mongolian gerbils were randomized into two experimental groups. Group 1 (n = 17) received a right ear gentamicin drug-induced lesion by unilateral labyrinthectomy (UL). Group 2 (n = 12) only received a right unilateral labyrinthectomy lesion. We measured the horizontal vestibulo-ocular responses in gerbils before and after the lesion. The gerbils received an angular acceleration stimulus and their eye movements were recorded. Results The gentamicin lesion resulted in a quicker recovery. Experimental groups underwent a similar time course of recovery. Statistical analysis showed no significant difference between the two groups. Both groups displayed adaptation to the lesion by day 21, but long-term compensation did not completely revert to the original pre-lesion state. Conclusions In a lesion requiring both static and dynamic compensation as in UL, the need for a static compensation may alter pre-existing compensation from a previous dynamic insult and require a new compensation. A previous lesion and adaptation is not preserved for a second lesion and the subject has to re-compensate. Therefore, surgical treatment in Meniere's disease such as UL can be considered without prior gentamicin treatment. Static and dynamic compensations do not appear to be as independent as previous studies have suggested.

No MeSH data available.


Related in: MedlinePlus