Vertical optokinetic nystagmus in Parkinson's disease.
Parkinson's disease (PD) is associated with a number of oculomotor deficits; however, little is known about changes in vertical optokinetic nystagmus (OKN) associated with PD. We recorded eye movements in 14 PD patients and 14 age-matched controls in response to large field OKN stimulation using stimulus velocities of 20 degrees /second and 40 degrees /second. We compared asymmetry of horizontal and vertical responses in the two groups. We found vertical OKN to be strongly asymmetric in PD with reduced gains for downward-moving stimuli. This asymmetry was significantly greater than that recorded in control volunteers. We postulate that this could result from an abnormal pursuit/early OKN system in PD leading to greater influence of the delayed OKN system.
Knapp
Christopher M
CM
Ophthalmology Group, Faculty of Medicine and Biological Sciences, University of Leicester, Leicester Royal Infirmary, Leicester, United Kingdom.
Gottlob
Irene
I
McLean
Rebecca J
RJ
Rajabally
Yusuf A
YA
Abbott
Richard J
RJ
Rafelt
Suzanne
S
Proudlock
Frank A
FA
D000368:Aged; D000369:Aged, 80 and over; D000704:Analysis of Variance; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D017120:Nystagmus, Optokinetic / Q000502:physiology*; D009759:Nystagmus, Pathologic / Q000209:etiology*; D009949:Orientation / Q000502:physiology; D010300:Parkinson Disease / Q000150:complications*; D012720:Severity of Illness Index