International Handbook of Clinical Hypnosis - E-Lib FK UWKS

CONVERSION DISORDERS 161
van der Kolk & Fisler, 1995). Van der Kolk suggests that dissociation is a characteristic
feature of traumatic memory van der Kolk & Fisler, 1995). In extreme stress the
`memory categorization system'Ðin which the hippocampus plays a central roleÐ
may break down and, as a result, memories are stored as fragmented affective and
perceptual states with little verbal representation van der Kolk, 1994). When these
individual sensory and affective imprints are incorporated into a coherent account,
the result is a semantic and therefore explicit memory. The processing of perceptual
features is more rapid than semantic processing. The former can take place on an
implicit, unconscious level, whilst the latter, precisely because it is concerned with
supplying meaning, is associated with consciousness Kihlstrom, 1992b).
It may be concluded from the above that traumas play a signi®cant role in the
development of dissociative disorders. The same cannot be said with any certainty
about the development of conversion disorders since, though they are frequently
regarded as dissociative disorders, there is a lack of systematic research into the
occurrence of traumas in their etiology.
Inconsistencies in the symptom pattern can be seen both in patients with a
conversion disorder and in those with a dissociative disorder. An example of the
former is that of a patient at our clinic who could not see, but was perfectly able to
walk across a room full of furniture without bumping into any of it. She was also able
to `guess' how many ®ngers were being held up in front of her. She was asked to look
in the direction of the ®ngers and call out the ®rst ®gure between one and ten that
came into her head. She never failed to give the correct answer. When asked, `But
how did you know that?', she replied, `You'll have to explain it to me. I can't see
anything and yet you tell me I keep getting the answer right.' There clearly is
perception, however much the patient might not realize it Kihlstrom, 1992b).
Various reports on these inconsistencies in dissociative disorders are reviewed by
Kihlstrom, Tataryn and Hoyt 1990) and Schacter and Kihlstrom 1989). For
example, Lyon 1985) describes a patient suffering from amnesia who was asked to
dial a telephone number at random. The number she dialed turned out to be her
mother's. In the same way, we asked a patient with total amnesia to give us her date
of birth. She did not know the answer. Then we asked her to say the ®rst date that
came into her head, and it was her birthday.
It would seem from the above that, despite the patients' protestations that they
cannot remember or have not seen things, these `not remembered' or `not seen'
facts or events still in¯uence their experiences, thoughts and behaviour see
Kihlstrom, 1992b).
CONVERSION DISORDER, DISSOCIATION AND HYPNOTIC
TRANCE
The so-called dissociative phenomena are explained by Kihlstrom as follows. The
information is not processed explicitly; the patient does not consciously perceive