Skip to main content
Article thumbnail
Location of Repository

Category deficits and paradoxical dissociations in Alzheimer's disease and Herpes Simplex Hencephalitis

By Dr. Keith Laws and Prof. Giuseppe Sartori


Most studies examining category specificity are single-case studies of patients with living or non living deficits. Nevertheless, no explicit or agreed criteria exist for establishing category-specific deficits in single-cases regarding the type of analyses, whether to compare with healthy controls, the number of tasks, or the type of tasks. We examined to groups of patients with neurological pathology frequently accompained with impaired semantic memory (19 patients with Alzheimer disease and 15 with Herpes Simplex Encephalitis). Category knowledge was examined using three tasks (picture naming, naming-to-description and features verification). Both patients groups were compared with aged- and education- matched healthy controls. The profile of each patients was examined for consistency across tasks and across different analyses; however both prove to be inconsistent. One striking findings was the presence of a paradoxical dissociation ( i.e., patients who were impaired on living things on one task and non living things on another task). The findings have significant implication for how we determine category effects and, more generall for the methods use to document double dissociation across individual cases in this literature

Topics: Neuropsychology
Year: 2005
OAI identifier:
Download PDF:
Sorry, we are unable to provide the full text but you may find it at the following location(s):
  • (external link)
  • (external link)
  • Suggested articles


    1. (2002). A case of domain-specific semantic deficits. In
    2. (1998). A leopard never changes its spots.
    3. (1998). Are living and non-living category-specific deficits causally linked to impaired perceptual or associative knowledge? Evidence from a category-specific double dissociation.
    4. (1984). Category specific semantic impairments. doi
    5. (1998). Category specific semantic loss in dementia of Alzheimer’s type. Functional–anatomical correlations from cross-sectional analyses.
    6. (1994). Category-specific semantic impairment in Alzheimer’s disease and temporal lobe dysfunction: A comparative study. doi
    7. (1975). Cerebral blood flow in dementia.
    8. (1984). Clinical diagnosis of Alzheimer disease: doi
    9. (1991). Dissociation between knowledge of living and non-living things in dementia of the Alzheimer’s type. doi
    10. (1997). Double dissociation of semantic categories in Alzheimer’s disease.
    11. (2003). Inflated and contradictory category naming deficits in Alzheimer’s disease? doi
    12. (1975). Mini-mental state’’: A practical method for grading the cognitive state of patients for the clinician.
    13. (1995). Naming without knowing and appearance without associations—Evidence for constructive processes in semantic memory. doi
    14. (2005). Testing for suspected impairments and dissociations in single-case studies in neuropsychology: Evaluation of alternatives using Monte Carlo simulations and revised tests for dissociations.
    15. (1996). The semantic memory impairment of Alzheimer’s disease: Category specific?
    16. (2003). Wanted: Fully operational definitions of dissociations in single-case studies.
    17. (2003). What are the facts of semantic category-specific deficits? A critical review of the clinical evidence.
    18. (2000). What the locus of brain lesion tells us about the nature of the cognitive defect underlying category-specific disorders: A review.
    19. (2005). When is category specific in dementia of Alzheimer’s type? doi

    To submit an update or takedown request for this paper, please submit an Update/Correction/Removal Request.