[Motor adaptation in the Bielschowsky head-tilt test in cases of superior oblique palsy].
To elucidate a motor adaptation phenomenon in the Bielschowsky head-tilt test in cases of superior oblique palsy, a gain of the otolith-ocular reflex was studied. The amplitude of ocular counter-rolling (OCR) of the non-paretic eye was measured with a photographic method, using limbal conjunctival marks as landmarks which were marked with indigo carmine. The average preoperative OCR of the non-paretic eye was 10.49 degrees at 30 degrees of head tilt to both sides, but after corrective surgery in the paretic eye the OCR of the non-paretic eye decreased to 8.43 degrees. To clarify the relation between OCR, duration of palsy and vertical deviation of the Bielschowsky head-tilt test (BHP), which was the difference of vertical deviation measured with the head tilted to the left and right shoulders at an angle of 30 degrees, the BHP/OCR ratio was calculated. We found no relation between BHP and OCR, but the BHP/OCR ratio increased proportionally in cases of long-standing palsy, From these results an increased BHP/OCR ratio could be an adaptive phenomenon caused by secondary innervational changes or muscle contracture to minimizing the contralateral head tilt to maintain binocular single vision.
Ohtsuki
H
H
Department of Ophthalmology, Okayama University Medical School, Japan.
Kishimoto
F
F
Kobashi
R
R
Watanabe
S
S
Okano
M
M
Furuse
H
H
D000222:Adaptation, Physiological; D000293:Adolescent; D000328:Adult; D000368:Aged; D002648:Child; D005133:Eye Movements; D006257:Head; D006801:Humans; D008875:Middle Aged; D009068:Movement; D009886:Ophthalmoplegia / Q000503:physiopathology*