The role of conceptual knowledge in object use Evidence from semantic dementia

• Published in: Brain (London, England : 1878) Vol. 123; no. 9; pp. 1913 - 1925
• Main Authors: Hodges, John R., Bozeat, Sasha, Ralph, Matthew A. Lambon, Patterson, Karalyn, Spatt, Josef
• Format: Journal Article
• Language: English
• Published: Oxford Oxford University Press 01.09.2000; Oxford Publishing Limited (England)
• Subjects: Aphasia, Primary Progressive - diagnosis; Aphasia, Primary Progressive - pathology; Aphasia, Primary Progressive - physiopathology; apraxia; Biological and medical sciences; Dementia; Headache. Facial pains. Syncopes. Epilepsia. Intracranial hypertension. Brain oedema. Cerebral palsy; Humans; Language Disorders - diagnosis; Language Disorders - pathology; Language Disorders - physiopathology; Medical sciences; Nervous system (semeiology, syndromes); Neurology; Neuropsychological Tests; object use; pantomime; Psychomotor Performance - physiology; semantic dementia; semantic memory; Semantics; Performance evaluation; Human; Memory disorder; Nervous system diseases; Semantic memory; Cognitive disorder; Daily living; Use; Psychometrics; Object; Neurological disorder; Dementia
• ISSN: 0006-8950; 1460-2156; 1460-2156
• DOI: 10.1093/brain/123.9.1913

It has been reported that patients with semantic dementia function well in everyday life and sometimes show striking preservation of the ability to use objects, even those specific objects for which the patient has degraded conceptual information. To explore this phenomenon in nine cases of semantic dementia, we designed a set of semantic tests regarding 20 everyday objects and compared performance on these with the patients' ability to demonstrate the correct use of the same items. We also administered a test of mechanical problem solving utilizing novel tools, on which the patients had completely normal ability. All but the mildest affected patient showed significant deficits of naming and on the visually based semantic matching tasks. Object use was markedly impaired and, most importantly, correlated strongly with naming and semantic knowledge. In a small number of instances, there was appropriate use of an object for which the patient's knowledge on the semantic matching tasks was no better than chance; but this typically applied to objects with a rather obvious relationship between appearance and use, or was achieved by trial and error. The results suggest that object use is heavily dependent upon object-specific conceptual knowledge, supplemented to some degree by a combination of visual affordances and mechanical problem solving.