Akinetopsia
As akinetopsia (of Greek α- a- "un-, not"; κίνησις Kinesis "movement"; ὄψις opsis "seeing"), also: Bewegungsagnosie is in medicine and psychology the impairment or inability to motion perception or recognition of Designated directions of movement and speeds . This is a very seldom occurring neuropsychological disorder for which, according to the current state of research, there are no therapy or cure options.
Pathophysiology
Already during the interconnection in the retina of the eye, the different perceptual qualities (color, shape, movement) are distributed to different cell types . The magnocellular system is primarily responsible for the perception of movements. The processing of movements and speeds in the visual cortex takes place under physiological conditions . Above all, the regions V2-V5 play a role, which as an associative visual cortex are assigned to the interpretation of what is seen.
It was discovered in primates that area V5 in particular has a high level of sensitivity to movement, so that damage to this region can lead to an akinetopia. A lesion can be caused by ischemia of the brain area (e.g. from a stroke or cerebral hemorrhage ); Alzheimer's also seems to have a negative impact. Since lesions in this area are not uncommon, it is assumed that the contralateral area can compensate for a unilateral failure. Thus, bilateral damage would be required to cause akinetopsia. In addition, an akinetopsia could be induced by transcranial magnetic stimulation on V5.
Characteristics
Akinetopsia patients describe movement as a series of static images. Other associative services such as color perception, spatial vision and the flicker fusion frequency are not impaired. In everyday life, akinetopsia is associated with considerable impairment, which makes the coordination of movement sequences such as pouring liquids or grasping objects very difficult. In addition, patients have problems communicating because they do not notice lip movements and facial expressions .
The first detailed description of an akinetopsia was taken by Zihl et al. on her patient "LM". This described, for example, coffee as "frozen" when it was poured and regularly caused the cup to overflow because she could not perceive the filling. In the presence of others she felt unsafe because she did not notice the people entering and they simply “appeared”.
diagnosis
The diagnosis of a akinetopsia often proves to be difficult because there are no standardized tests. Today, computer-aided test procedures are mainly used to examine the patient's reaction to movement. According to the current state of research, therapy or healing options are not yet known.
literature
- Peter Berlit: Clinical Neurology. 2nd edition, Springer Medizin Verlag, Heidelberg 2006, ISBN 3-540-01982-0 .
Individual evidence
- ↑ a b c Peter Berlit: Clinical Neurology. P. 573
- ^ Rizzo M., Nawrot M .: Perception of movement and shape in Alzheimer's Disease. In: Brain , 121st Edition, 1998, pp. 2259-2270. ( pdf, 205 kB )
- ^ Beckers G., Zeki S .: The consequences of inactivating areas V1 and V5 on visual motion perception. In: Brain , 118th Edition, 1995, pp. 49-60.
- ↑ Hans-Otto Karnath , Peter Thier: Neuropsychology. 2nd edition, Springer Medizin Verlag, Heidelberg 2006, p. 43.