Second edition

02.qxd 3/10/08 9:32 AM Page 59
Section 2.1, is a form of aphasia in which patients are
unable to comprehend the meaning of the word, although
they are able to recognize environmental sounds and the
spoken word as a word.
TREATMENT
Speech/language therapy may enable the patient to develop
compensatory strategies.
Prosopagnosia
The term prosopagnosia is derived from the Greek word
for face, ‘prosopon’, and refers to a remarkable condition in
which patients are unable to recognize others by looking at
their faces (Sergent and Poncet 1990).
CLINICAL FEATURES
Patients with prosopagnosia, although able to recognize
faces as faces, and indeed able to describe accurately the
facial features of others, are yet unable to identify the other
person (Tranel et al. 1988). Remarkably, these patients,
although unable to identify others by their facial features,
may be able to identify them by other features, such as their
voice, dress, or characteristic gait (Damasio et al. 1982b).
Some examples may help to clarify this remarkable condition.
In one case, the patient, a party to a lawsuit, had
come to identify his own lawyer by the setting in which the
two of them generally met, namely the lawyer’s office; all
went well until trial, when the patient, unable to recognize
people in the courtroom, went up to the opposing counsel
and began to discuss confidential details of the case ‘with
disastrous consequences’ (Pevzner et al. 1962). In another
case, a patient had come to rely on his wife’s clothing as a
means of identifying her: at a party, he found himself
unable to recall what she had put on and although she
walked right by him he failed to recognize her (Hecaen and
Angelergues 1962). In a similar vein, another patient ‘failed
to recognize a physician who had just examined him after
the doctor had substituted his suit jacket for his white coat’
(Hecaen and Angelergues 1962). Finally, and most remarkably,
some patients are not able to recognize themselves
when they look in the mirror (Damasio et al. 1980).
As might be expected, such patients, in addition to
being unable to recognize old acquaintances by their facial
features, are also unable to utilize facial features to recognize
new acquaintances (Malone et al. 1982).
ETIOLOGY
Prosopagnosia generally occurs secondary to bilateral
lesions of the inferior occipitotemporal area (Cohn et al.
1986; Damasio et al. 1980, 1982b; Meadows 1974b;
Pevzner et al. 1962); rarely prosopagnosia may occur secondary
to a unilateral occipitotemporal lesion on the right
2.9 Agnosias 59
(Cohen et al. 1994; Landis et al. 1986, 1988; Rosler et al.
1997; Wada and Yamamoto 2001). In all these cases, the
prosopagnosia occurred as part of a stroke syndrome, generally
secondary to ischemic infarction.
Prosopagnosia has also been noted secondary to resection
of the posterior portion of the right temporal lobe
(Mesad et al. 2003) and after a right hemispherectomy
(Sergent and Villemure 1989). There are also rare reports
of progressive prosopagnosia occurring secondary to progressive
atrophy of the right temporal lobe (Evans et al.
1995; Joubert et al. 2003).
Interestingly, prosopagnosia may also occur on a paroxysmal
basis as a simple partial seizure: in one case, a patient
with left occipitotemporal scarring had seizures characterized
by a sense of ‘flickering lights’ followed by a brief
episode of prosopagnosia (Agnetti et al. 1978).
Finally, there are also rare reports of prosopagnosia
occurring on a developmental basis (Kress and Daum 2003).
DIFFERENTIAL DIAGNOSIS
Anomic aphasia may render patients incapable of coming
up with the name of another person; in such cases, however,
in contrast with prosopagnosia, there is no difficulty in recognizing
the other person or in specifying the relationship
that exists between the patient and the other person.
TREATMENT
Speech/language and occupational therapy may assist the
patient in developing compensatory strategies.
Topographagnosia
At the outset, it should be noted that there is some debate
regarding the definition of topographagnosia and, consequently,
the reader, in perusing journal articles, should pay
particular attention to the definition peculiar to the
authors of the article. In this text, topographagnosia refers
to a condition in which patients, despite adequate memory
and vision, are unable to find their way in surroundings
that had not previously caused any difficulty. This group of
patients may be further subdivided into two types, namely
one wherein the difficulty lies in an inability to recognize
familiar landmarks (termed here ‘landmark agnosia’) and
another wherein, despite a preserved ability to recognize
landmarks, there is an inability to utilize these landmarks
in deciding which way to proceed (herein referred to as
‘topographical disorientation’).
CLINICAL FEATURES
Finding one’s way depends both on recognizing landmarks
and on knowing which way to proceed upon encountering
those landmarks. Thus, if one’s accustomed route home