What is Perceptual Agnosias?

Perceptual Agnosias

Introduction

Agnosia is a clinical condition characterized by disordered perception situated at an intermediate stage between primary sensory defect and general intellectual dysfunction (Hécaen & Albert, 1978; Mather, 2009). Agnosias are described as the loss of ability to recognize objects, persons, sounds, shapes, or smells while the specific sense is not impaired nor is there any significant memory loss (Mather, 2009) A person can have a deficit in the visual, auditory, olfactory, somatosensory system even the sense of hearing, smell, or touch functions normally (Gazzaniga, Ivry & Mangun, 2014). The term was coined by Sigmund Freud, who derived it from the Greek a – (“without”) and agnosis (“knowledge). According to Riddoch et al. (2008) agnosias were first described by Liassauer in 1890. Liassauer (1890) proposed the existence of apperceptive agnosia, Kussmaul (1877) first described a patient with pure word deafness, and Bernard (1889) noted an amusia. Since that time, many other cases have been reported (Mendez, & Geehan, 1988).

Auditory Agnosia

Auditory agnosia is a rare cortical auditory impairment and a cognitive disorder. It refers to the inability to recognize sounds, nonverbal, and / or acoustic stimuli despite adequate hearing measured by standard audiometry. Auditory agnosia is also defined as the inability to process environmental sounds and speech, in the absence of aphasia and the defective recognition of auditory stimuli in the context of preserved hearing (Hécaen & Albert 1978; Motomura, Yamadori, Mori, & Tamaru, 1986; Miceli, Conti, Cianfoni, Di Giacopo, Zampetti, & Servidei, 2008; Zhang, Kaga, & Hayashi, 2011).

Clinical reports of auditory agnosia in patients include inability to recog...

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