The patient performed best in the purely tactile condition and very poorly in the visual condition. She did not benefit from the visual information in the tactile-visual condition either. The patient reported that the difficulty was between her finger and her eyes. She could not follow her finger with her eyes if she moved her finger too fast. Additional experiments
In 1994, several other observations of LMs capabilities were made using a stimulus with a random distribution of light squares on a dark background that moved coherently. With this stimulus, LM could always determine the axis of motion (vertical, horizontal), but not always the direction. If a few static squares were added to the moving display, identification of direction fell to chance, but identification of the axis of motion was still accurate. If a few squares were moving opposite and orthogonal to the predominant direction, her performance on both direction and axis fell to chance. She was also unable to identify motion in oblique directions, such as 45, 135, 225, and 315 degrees, and always gave answers in cardinal directions, 0, 90, 180, and 270 degrees. "TD"
In 2019, Heutink and colleagues described a 37-year old female patient (TD) with akinetopsia, who was admitted to Royal Dutch Visio, Centre of Expertise for blind and partially sighted people. TD suffered an ischaemic infarction of the occipitotemporal region in the right hemisphere and a smaller infarction in the left occipital hemisphere. MRI confirmed that the damaged brain areas contained area V5 in both hemispheres.
There was no restriction in her visual field and no scotoma. Disturbance of movement vision
LMs impression of movement depended on the direction of the movement (horizontal vs vertical), the velocity, and whether she fixated in the center of the motion path or tracked the object with her eyes. Circular light targets were used as stimuli.In studies, LM reported some impression of horizontal movement at a speed of 14 degrees of her predetermined visual field per second (deg/s) while fixating in the middle of the motion path, with difficulty seeing motion both below and above this velocity. When allowed to track the moving spot, she had some horizontal movement vision up to 18 deg/s. For vertical movement, the patient could only see motion below 10 deg/s fixated or 13 deg/s when tracking the target. The patient described her perceptual experience for stimulus velocities higher than 18 and 13 deg/s, respectively as "one light spot left or right" or "one light spot up or down" and "sometimes at successive positions in between", but never as motion. Motion in depth
To determine perception of motion in depth, studies were done in which the experimenter moved a black painted wooden cube on a tabletop either towards the patient or away in line of sight. After 20 trials at 3 or 6 deg/s, the patient had no clear impression of movement.