caused by brain damage resulting in lesions to one side of the parietal lobe. Auditory extinction appears to be a rather common phenomenon in the acute state of a vascular disease. The acute state of the vascular disease usually leads to neglect which then in turn leads to the auditory extinction. The number of lesions causes an additive effect when occurring in combination with a recent damage. When it comes to treating and recognizing the occurrence of auditory extinction most sound can still be perceived with the other ear. The nature of sound, which possess directionality but still fills space, makes it more amenable to misattribution of source location. This is called the ‘prior entry’ effect. This is when a stimulus occurring at an attended location receives privileged access to awareness relative to one occurring at an unattended location. Chemical extinction Little is known on the side of occurrence of unilateral extinction or neglect for sensory modalities, which are traditionally thought to project to the brain in a predominantly uncrossed fashion, such as olfaction and taste. To date, only a limited number of investigations concerning the suppression of (or competition among) spatial information processed through the so-called chemical senses have been reported. A number of various different reasons may account for this lack of research. First, the distinction between pure chemical versus somatosensory information is often problematic. Second, it is widely assumed that olfaction and taste are senses that are not specialized for conveying spatial information. Olfactory extinction Multiple case studies and investigations have been conducted on unilateral neglect within the visual, auditory, and tactile sensory modalities, but only three case studies have been reported on neglect within the olfactory sensory modality. It is still unclear whether humans can localize at all the source of the olfactory stimulation by distinguishing between odors that are processed through the right versus the left nostril. This is particularly true when the stimulus is a pure odorant rather than trigeminal, that is when the odor does not cause any somatosensory stimulation that is known to be encoded by the trigeminal system. It was discovered that when pure odorants such as hydrogen sulfide or vanillin were used as stimulants localization was random. On the other hand, stimulation with carbon dioxide or menthol yielded identification rates of more than 96%. These results established the fact that directional orientation, considering single momentary odorous sensations, can only be