visual search performance compared to those with MCI who did not progress to dementia in the same time period. It has also been suggested that deficits in visual selective attention in MCI patients appears to be dependent on task characteristics, requirements, and the type and availability of the cue. These findings are also consistent with neuropathological changes seen in early AD patients in areas such as the cholinergic system, and prefrontal and parietal regions. When the given task requires working memory, deficits in visual selective attention and performance are observed in MCI patients, however, it is noted that controlled processing are generally unaffected. Auditory cues to aid visual selective attention in tasks were shown to improve performance, due to reduction in demand, and it is therefore apparently that MCI patients rely on exogenous information to aid in attention allocation. Alzheimer's disease Alzheimer's disease is the most common form of dementia, which approximately two thirds of individuals with dementia are diagnosed with. It is the major cause of dementia in older adults. AD has an insidious onset with worsening prognosis, and results in deterioration in memory, spatial abilities, language, and many other cognitive functions, including visual selective attention. Alzheimer's disease damages and kills brain cells. Compared to a healthy brain, the brain of someone with Alzheimer's has fewer cells and there are fewer connections among surviving cells. This inevitably leads to brain shrinkage. This disease characterises two types of abnormalities: plaques and tangles. Plaques are clumps of a protein called beta-amyloid. They may damage and destroy brain cells by interfering with cell-to-cell communication, among others. The collection of beta-amyloid on the outside of brain cells is thought to be implicated in the cause of this disease. Tangles are threads of another protein, tau. Tau twist into abnormal tangles inside brain cells, resulting in failure of the transport system, which is also implicated in the death of brain cells. The brain relies on this internal support and transport system in order to carry nutrients and essential materials, requiring the normal structure and functioning of tau. It has been suggested that attentional decline in mild AD is perhaps contingent on degeneration in the cerebral network for attention. This network includes the occipital lobe, adjacent temporal and parietal areas, frontal lobe, and subcortical regions. As the disease progresses, the prefrontal cortex begins to degenerate, and lower SAS systems lose their autonomic features. Visual selective