Theinitial phase of AD generally includes anterograde amnesia which leadprogressive decline in retrieval of memory of the collection of past experienceoccurred at particular time and place (episodic memory). Some memory tests mayreveal deficits in formation of new memories and consolidation into long termmemories. These tests have proven that AD patient show loss of memory instantlyafter a time delay and do not improve even after memory cues are given.
Impairedsemantic memory and language also may be considered as early symptoms duringthe progression of AD. These difficulties are supposed to result from thedegenerative disease mechanisms causing damages in the interconnected neuronsof brain involved to memorise times, places, associated emotions and other contextuals(McKhann,Knopman et al. 2011).Tests of verbal fluency may detect impairment with the tendency to performrelatively worse on tasks which is based on generation of words from aparticular category with respect to generation of words beginning with a particularletter of the alphabet. Poor performance can be typically observed onconfrontation naming tests and semantic categorization (Bondi,Salmon et al. 2009; Weintraub, Wicklund et al.
2012).Decline in executive functioning can be checked on tests of complex sequencing,mental flexibility, problem solving and working memory. Deficits in these areasmay be detected using some tests such as the Porteus Maze task, Tower of Londonpuzzle, Wisconsin Card Sorting Task and Trail-Making Test. All test are usefulto check decline in performing activities of daily living (Weintraub,Wicklund et al. 2012).
Althoughdificits in visuospatial functioning are not early features of AD, but itdeteriotes over the period of the disease progression. In particular,visuoconstructional deficits may be observed on the Clock drawing task and oncomplicated copying tasks using drawing (Lezak2004; Malamut and Ryan 2008).The AD patient with impaired visuoconstructional deficits tends to performtheir copy of design close to the stimulus item.
Additionally, visuoperceptualand visual orientation abilities may be become progressively disturbed withtime.Inadvanced stage extrapyramidal motor signs are likely more prominent in ADpatient. Patients may suffer from impairment in ideomotor (Unconscious motoractivity) and ideational (conscious motor activity), even in the early stagesof the disease progression (Malamutand Ryan 2008).This causes inability to perform daily routine tasks independently (Lezak2004).