Differential impairments in recalling people's names: A case study in search of neuroanatomical correlates
Introduction
Evidence from a number of sources including positron-emission-tomographic studies 18, 26, 35, 36, 42, 58and single case reports 12, 13, 14, 50makes it likely that circumscribed cortical regions represent specific semantic attributes. After certain kinds of brain damage patients may no longer be able to name and describe living objects such as a snake or a crocodile, while they are still able to name and describe objects like a tent or a compass 11, 61. A special class of semantic termini is defined by proper names and—as a specific subset—by people's names, and may be selectively impaired by cortical damage 5, 25, 30, 37, 46, 47, 48, 49.
Possibly dependent on specific features of the impairment in name reproduction, left thalamic 6, 30, 39, left temporal 22, 37, 49, left parieto-occipital [47]and left-hemispheric fronto-temporal damage 25, 48have been found to result in impairment for proper names. While lesion data are divergent, Damasio and colleagues [9]conducted word-retrieval experiments with both brain damaged patients and normal subjects undergoing positron-emission-tomography (PET). For both groups of subjects, retrieval of words signifying concrete entities (names for persons, animals, tools) depended on different regions of the temporal lobe, whereas naming actions activated the left frontal cortex. In a study likewise based on PET data, Martin et al. [36]found that naming pictures of animals was associated with bilateral activations of the ventral temporal lobe, Broca's area and the medial occipital lobe.
With regard to the nature of the deficit, anomia may or may not be embedded in the context of more widespread amnesia. Based on different assumptions, numerous authors have suggested that anomia for proper names constitutes a retrieval deficit 15, 22, or, more specifically, an inability to form—for retrieval—new associations between the meanings of words and their phonological forms [49].
Several further findings have helped to clarify the cognitive aspects involved in naming people. Flude and colleagues [17]assumed that names are stored separately from semantic information about people, and Damasio et al. [9]even hypothesized segregated neural systems subserving conceptual and word-form knowledge for the same stimulus. From experimental studies with normal subjects, Valentine et al. [57]concluded that name recognition units mediating between word recognition and the access to identity-specific semantics exist. Similarly, Fery and colleagues [15]presumed that anomia is caused by an impaired access to intact phonological representations from semantic memory. On the other hand, as there is evidence that names (e.g. `Baker') with name–occupation homophones are more difficult to recall than occupations (e.g. baker) [38], this disadvantage for proper names cannot be attributed to differences in the phonological word-form [7], but has to be discussed in the context of word meaning. Indeed, proper names seem to be unique because of their low meaningfulness; they therefore work as `pure referring expressions' [48]without describing any properties or attributes of the corresponding persons [25]. Moreover, Burton and Bruce [4]emphasized the uniqueness of a name to a given person. A survey of current models and a discussion of recent cases can be found in Cohen and Burke [8].
We here report a new case of a selective anomia for people's names focusing on its neuronal correlates and on the nature of the distinct impairments of different memory systems.
Section snippets
Case report
CU is a 61-year-old, right-handed, female music teacher who came to our attention with conspicious problems in remembering names. Following 10 days of indisposition, symptom-onset on 10 December 1995 presented with a bad left-sided headache, nominal aphasia and transient confusion.
She suffered an ischaemic/embolic (?) insult in the left medial temporal lobe probably caused by an atrial septum aneurysm. Acute computer tomographic and magnetic resonance imaging (MRI) scans showed an oedema zone
Discussion
We have described a patient with a quite selective—category-specific—anomia for people's names, who was nearly perfect in naming pictures or generating common and proper names of other semantic categories. When the words belong to categories of common names (for example, clothes) as well as proper ones (such as cities), results just below average can be due to a continuing slight general anomia rather than selectively account for another special type of anomic disturbance. Furthermore, the
Acknowledgements
We thank the patient and her mother for their cooperation in all testing procedures. We also thank Ralf Babinsky for fruitful comments and David Emmans for improvement of the English text. Research was supported by the German Research Council (grant Ma 795/15-2).
References (67)
- et al.
Are semantic systems separately represented in the brain? The case of living category impairment
Cortex
(1994) - et al.
Can recognition of living things be selectively impaired?
Neuropsychologia
(1991) - et al.
Semantically-bounded anomia: Implications for the neural implementation of naming
Neuropsychologia
(1992) - et al.
Personal name anomia: A single case study
Cortex
(1995) - et al.
Face processing and name retrieval in an anomic aphasic: Names are stored separately from semantic information about familiar people
Brain and Cognition
(1989) Functional mapping of verbal memory and language
Trends in Neuroscience
(1994)Selective impairment of the retrieval of people's names: A case of category specifity
Cortex
(1995)- et al.
Anomia for people's names
Neuropsychologia
(1994) - et al.
Proper name anomia
Cortex
(1992) Diencephalic amnesia: A reorientation towards tracts?
Brain Research Reviews
(1988)