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

UL lesion at 0.5 Hz and 60° /sec depicting gain values over time (x-axis: logarithmic scale).
© Copyright Policy
Related In: Results  -  Collection


getmorefigures.php?uid=PMC4835328&req=5

FI0371or-4: UL lesion at 0.5 Hz and 60° /sec depicting gain values over time (x-axis: logarithmic scale).

Mentions: Twelve gerbils underwent right hemi-labyrinthectomy lesions. The VOR time points for the UL experiments were 3 hours, 6 hours, 9 hours, 12 hours, day 1, 3, 7, 14, and 21. Again, depending on the signal quality, we obtained data from at least 5 animals at each specific time point for all frequencies and velocities, with most reaching the maximum n. As depicted in Fig. 2, the UL-only animals showed a bias velocity on the first day, unlike the gentamicin animals, but this velocity started to decline after the first day post lesion. The normalized gain versus time graph of the gerbils with UL lesion for 0.5 Hz frequency at 60°/sec is shown in Fig. 4. The gains decreased at 3 hours and 6 hours, reaching their lowest value at 24 hours, at which point they began to increase again. As previously described and depicted in the Figure, the compensation for the head movements toward the contralateral side of the lesion (left) was slightly more than the ipsilateral side (right) during the first 7 days. The compensation is not as evident as that seen in the gentamicin animals, as the gains reach ∼31–59% of the original gains, with half cycles ranging 31–56% for the left eye and 41–59% for the right eye.


Neurovestibular Compensation following Ototoxic Lesion and Labyrinthectomy.

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

UL lesion at 0.5 Hz and 60° /sec depicting gain values over time (x-axis: logarithmic scale).
© Copyright Policy
Related In: Results  -  Collection

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

FI0371or-4: UL lesion at 0.5 Hz and 60° /sec depicting gain values over time (x-axis: logarithmic scale).
Mentions: Twelve gerbils underwent right hemi-labyrinthectomy lesions. The VOR time points for the UL experiments were 3 hours, 6 hours, 9 hours, 12 hours, day 1, 3, 7, 14, and 21. Again, depending on the signal quality, we obtained data from at least 5 animals at each specific time point for all frequencies and velocities, with most reaching the maximum n. As depicted in Fig. 2, the UL-only animals showed a bias velocity on the first day, unlike the gentamicin animals, but this velocity started to decline after the first day post lesion. The normalized gain versus time graph of the gerbils with UL lesion for 0.5 Hz frequency at 60°/sec is shown in Fig. 4. The gains decreased at 3 hours and 6 hours, reaching their lowest value at 24 hours, at which point they began to increase again. As previously described and depicted in the Figure, the compensation for the head movements toward the contralateral side of the lesion (left) was slightly more than the ipsilateral side (right) during the first 7 days. The compensation is not as evident as that seen in the gentamicin animals, as the gains reach ∼31–59% of the original gains, with half cycles ranging 31–56% for the left eye and 41–59% for the right eye.

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