PSP with Complete Ophthalmoplegia and Inability to Suppress the VOR

𝗢𝗿𝗶𝗴𝗶𝗻𝗮𝗹 𝗗𝗲𝘀𝗰𝗿𝗶𝗽𝘁𝗶𝗼𝗻: This is a 65-year-old woman presenting with visual complaints in the setting of advanced progressive supranuclear palsy (PSP). She had complete vertical and horizontal ophthalmoplegia, although the vestibulo-ocular reflex (VOR) could overcome the horizontal gaze palsy (but not the vertical gaze palsy). When VOR suppression was tested by having the patient look at the light of the camera while rotating (combined eye-head movement) in a chair, the intact VOR drove the eyes to the right when the chair was turned to the left and to the left when the chair was turned to the right. In this case, she was completely unable to suppress her VOR. Normally, when VOR suppression (VORS) is impaired, the appearance is choppy or saccadic - this is explained by saccades supplementing the impaired pursuit/VORS response. In her case, she was unable to generate saccades, so the eyes drifted laterally (due to an intact VOR) without a mechanism (i.e., saccades) to get them back to the fixation target. MRI demonstrated ‘Mickey mouse sign', an appearance created by midbrain tegmentum atrophy on axial images. 𝗡𝗲𝘂𝗿𝗼-𝗼𝗽𝗵𝘁𝗵𝗮𝗹𝗺𝗼𝗹𝗼𝗴𝘆 𝗮𝗻𝗱 𝗡𝗲𝘂𝗿𝗼-𝗼𝘁𝗼𝗹𝗼𝗴𝘆 𝗧𝗲𝘅𝘁𝗯𝗼𝗼𝗸 𝗟𝗲𝗴𝗲𝗻𝗱: This patient had complete vertical and horizontal ophthalmoplegia, although the VOR could overcome the horizontal gaze palsy (but not the vertical gaze palsy). When VOR suppression was tested by having the patient look at the light of the camera while rotating (combined eye-head movement) in a chair, the intact VOR drove the eyes to the right when the chair was turned to the left and to the left when the chair was turned to the right. In this case, she was completely unable to suppress her VOR. Normally, when VOR suppression (VORS) is impaired, the appearance is choppy or saccadic - this is explained by saccades supplementing the impaired pursuit/VORS response. In her case, she was unable to generate saccades, so the eyes drifted laterally (due to an intact VOR) without a mechanism (i.e., saccades) to get them back to the fixation target. MRI demonstrated ‘Mickey mouse sign', an appearance created by midbrain tegmentum atrophy on axial images. https://collections.lib.utah.edu/ark:/87278/s6wx2sks