Attention is essential to focus on specific aspects of the environment and ignore irrelevant stimuli. There are different types of attention, such as selective, shifting and divided attention, each serving a different purpose, but all are important for information processing in the brain.
Impairments of attention can affect all cognitive functions. Without attention, a person's perception of the world around them may seem confusing, or they may have difficulty performing certain activities. For example, people with selective attention deficit often have difficulty filtering distracting stimuli such as background noise when completing tasks. These tasks often take more time to complete or may not be performed satisfactorily. For people with Balint syndrome, they are unable to attend to more than one object. If two objects, such as a fork and knife, are placed in front of them, they only report seeing one object, despite having a properly functioning visual system.
Neglect is a term used to define a failure to respond and orient to stimuli on the opposite side of a brain lesion. People with damage to their right parietal lobe often neglect things on their left side. For example, they may not notice food on the left half of their dinner plate or fail to orient to a vehicle approaching from the left. A diagnosis of neglect can only be made after screening for visual system deficits.
If untreated, people with left neglect experience impairments in function. For example, when putting on pants or sweaters, only the right leg and arm are dressed. Putting on make-up is also an issue for some people as they neglect the left side of their face. Reading can also be a challenge as people do not attend to words on the page's left side. Occupational therapists play an essential role for people living with attention disorders to help them complete their daily activities independently.
Reference: Grieve, June, and Linda Maskill. Neuropsychology for Occupational Therapists: Cognition in Occupational Performance. John Wiley & Sons, 2013.