I welcome your reminder about Ramachandran, but wonder if there are
some confusions that need straightneing out regarding Capgras and
prosopagnosia.
I had cited Capgras syndrome in my much earlier response to this, and
in that (emphasising possible dissociations between visual experience
and the normal emotional correlates) in the context of references to
"derealizattion", etc.
Tore is trying to emphasize the impoortance of visual phenomena
separate from these "emotional/experiential" aberrations.
(1) The visual aspect of the Capgras experience is apparently normal;
patients readily agree that the "imposters" LOOK like there actual
relatives.
(2) There is no obvious relationship bettween Capgras and
prosopagnosia. People with prosopagnosia cannot associate the visual
appearance of a face with tthe person it belongs to. When learning the
identity of the person they are looking at (e.g. through voice, they
have no trouble accepting that this is really the person they know. (I
studied such a patient longitudinally, over several years, with
interesting findings regarding the evolution of her "visual" problems;
reported at INS meeting in New Orleans--perhaps 10 years ago? 11?)
Of course, there is more than one kind of prosopagnosia, one involving
a more fundamental visual analysis problem, perhaps, the other more of
a visual memory problem, and conceivably there may be some room for
involvement of one or the other type with emotional dissociation so as
to overlap with Capgras, but...
As regards strictly "visual" aspects: at an early stage in her
(partial) recovery, my patient had some more general visual and/or
visual memory problems, but these eventually resolved down to problems
in recognizing people, animals, and "that sort of thing".
Testing during that period found her able to draw a very good copy of
line drawings of various animals, but without a clue as to what it was
she was drawing (othr than"some kind of animal")--i.e. no "visual"
problem in the usual sense.
F. Frank LeFever, Ph.D.
New York Neuropsychology Group
In <37938E1C.F5545928 at pacbell.net> Richard McCollim
<mapache at pacbell.net> writes:
>>Tore,
>> The real authority on this subject has to be V.S. Ramachandran.
In his
>recent work "Phantoms in the Brain", he deals with the most bizarre
visual
>phenomena you can think of. He shows convincingly that some outlandish
brain
>disorders that most people regard as a psychiatric problem can be
explained in
>terms of known brain circuity.
>> He deals with cases of actual physical injury to various parts
of the
>brain and how they affect visual perception and personality. This is
>absolutely the best book on the subject, highly readable, and very
relevant to
>the case you describe.
>> You want bizarre? How about Capgras' syndrome? These subjects come
to
>regard family memebers and close acquaintances as impostors. He
rejected
>Freudian interpretations involving family conflicts when he found a
patient
>who had suffered head trauma in a car accident and afterward claimed
that his
>pet poodle was an impostor and that the real Fifi was living in
Brooklyn.
>There are actually areas in the brain that deal specifically with the
>recognition of faces, and a stroke or other trauma can render it
ineffective.
>This, he believes, is the more likely explanation.
>> There is lots more, from phantom limb syndrome to idiot savants. A
very good
>book.
>Another good one is "Space and Sight" by M. von Senden, published in
German in
>1932 and in English in 1960.
>>--Richard
>-------------------------------------------------
>Tore Lund wrote:
>>> Nick Medford wrote:
>> >
>> > I'm trying to picture the reaction of your average ophthalmologist
being
>> > asked to see such a patient. (Is this what you mean by "vision
>> > specialist"?)
>>>> Agreed, "vision specialist" was a rather silly term. What I had in
mind
>> was researchers specifically interested in the mechanics of visual
depth
>> perception, and most of those are not even doctors, I suppose.
>>>> What I have been trying to elicit is reports of unusual visual
>> perspectives and possible explanations for them in terms of this or
that
>> model of vision. Sorry if that has not been clear.
>> --
>> Tore Lund <tl001 at online.no>
>
