What does astereognosis mean?
Astereognosis is the neurological inability to recognize familiar objects by touch alone, even though the sense of touch itself remains intact. A person with this condition can feel an object's shape, texture, weight, and temperature, but cannot use that information to identify what the object is — a key, a coin, or a pen — without seeing it. The term comes from Greek roots meaning 'not knowing solid things,' and it is classified as a form of tactile agnosia. Astereognosis most often results from damage to the parietal lobe, the region of the brain that integrates sensory information, and it may affect one or both hands depending on the site of injury. Clinicians detect it through simple bedside tests in which patients identify common items with their eyes closed. Because it can signal lesions such as stroke or tumor, astereognosis is a valuable diagnostic finding in neurological examination.
nounThe inability to recognize familiar objects by touch alone, despite intact sensation and no impairment of the primary sensory pathways. It is a form of tactile agnosia, typically resulting from damage to the parietal lobe of the brain.
- Loss of the ability to identify objects by touch alone despite preserved elementary tactile sensation, usually due to parietal lobe damage.
"After her stroke, the patient could feel the coin in her hand but, owing to astereognosis, could not identify it without looking."
"Neurological testing revealed astereognosis: the patient could describe the texture of the object but not name it."
"A bedside test for astereognosis involves asking the patient to identify a common item, such as a key or coin, with eyes closed."
Rarely used; the word is normally treated as an uncountable clinical sign.
"Bilateral astereognoses were noted on examination."
Your fingers can feel every detail of a key — its ridges, its weight, its cold metal — yet with astereognosis your brain still can't tell you it's a key.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Etymology of astereognosis
Astereognosis derives from Greek elements: the negative prefix 'a-' (without), 'stereos' (solid, three-dimensional), and 'gnosis' (knowledge), literally meaning 'lack of knowledge of solid objects.' The term was coined in late 19th-century neurology as clinicians began systematically mapping sensory deficits to brain lesions. It shares its '-gnosis' root with related medical terms such as agnosia, diagnosis, and prognosis, all of which concern forms of knowing or recognition.
Related word forms
How astereognosis is actually used
Astereognosis is a technical term used almost exclusively in neurology, clinical medicine, and neuropsychology; it is rarely encountered in general conversation. It is always treated as an uncountable clinical sign rather than a common noun.
Easily confused with astereognosis
Stereognosis is the normal ability to identify objects by touch, whereas astereognosis is the loss or absence of that ability.
Agnosia is the general term for failure to recognize sensory stimuli in any modality, while astereognosis refers specifically to the tactile (touch-based) form.