Which term describes the inability to identify objects by touch?

Which term describes the inability to identify objects by touch?

• A. Homonymous hemianopsia
• B. Astereognosis
• C. Unilateral neglect
• D. Anosognosia

Answer: (B)

Identifying an object by touch requires higher-level processing in the somatosensory association areas of the parietal lobe, where tactile cues are integrated with memory to recognize what is being felt. When this area is damaged, a person can still feel textures, shapes, and weights, but cannot name or identify the object solely from touch. This specific deficit is called astereognosis, and it points to a cortical processing problem rather than a peripheral sensation loss—so basic touch and proprioception tests are often normal, while object identification with the hands is impaired. Other conditions involve different domains: a visual field loss such as a homonymous hemianopsia is about vision, not touch; unilateral neglect is an attentional problem that may affect scanning and awareness of objects on one side but isn’t a pure failure to identify by touch; anosognosia is a lack of awareness of one's own deficits, not specifically about tactile object recognition.

Identifying an object by touch requires higher-level processing in the somatosensory association areas of the parietal lobe, where tactile cues are integrated with memory to recognize what is being felt. When this area is damaged, a person can still feel textures, shapes, and weights, but cannot name or identify the object solely from touch. This specific deficit is called astereognosis, and it points to a cortical processing problem rather than a peripheral sensation loss—so basic touch and proprioception tests are often normal, while object identification with the hands is impaired.

Other conditions involve different domains: a visual field loss such as a homonymous hemianopsia is about vision, not touch; unilateral neglect is an attentional problem that may affect scanning and awareness of objects on one side but isn’t a pure failure to identify by touch; anosognosia is a lack of awareness of one's own deficits, not specifically about tactile object recognition.