Biomedical subjects

Rafaële J C Huntjens

Publications and source records attributed to Rafaële J C Huntjens.

8 recordsLinked to original sources

PubMed2006

Memory transfer for emotionally valenced words between identities in dissociative identity disorder.

The present study aimed to determine interidentity retrieval of emotionally valenced words in dissociative identity disorder (DID). Twenty-two DID patients participated together with 25 normal controls and 25 controls instructed to simulate DID. Two wordlists A and B were constructed including neutral, positive and negative material. List A was shown to one identity, while list B was shown to another identity claiming total amnesia for the words learned by the first identity. The identity claiming amnesia was tested for intrusions from list A words into the recall of words from list B and recognition of the words learned by both identities. Test results indicated no evidence of total interidentity amnesia for emotionally valenced material in DID. It is argued that dissociative amnesia in DID may more adequately be described as a disturbance in meta-memory functioning instead of an actual retrieval inability.

Adult↗

PubMed2006

The time course of spatial memory processing in the two hemispheres.

Previous studies have shown that memories for positions are often distorted in systematic ways, indicating the influence of categorical positions codes which can bias responses in object-relocation tasks towards stored spatial prototypes. In the present study, we examined the time course of these categorical influences. Subjects had to relocate the position of a tachistoscopically presented dot within a circle, which could appear in either the left visual field (i.e. initially to the right hemisphere) or the right visual field (i.e. initially to the left hemisphere). Three retention intervals between presentation and relocation were used: 500, 2000 and 5000 ms. Performance was most accurate with left visual field/right hemisphere presentation. Systematic distortions were found for angular errors (dot relocations regressed towards the 45 degrees with a quadrant) as well as for radial errors (dots were replaced in the direction of the circle's circumference, and this more so when the dot was further away from the circumference). Importantly, these categorical biases became stronger with retention interval and initial left hemispheric processing. These results suggest that categorical spatial coding might be the default manner in which spatial information is remembered over time. Finally, the left hemisphere may play an important role for such a categorical spatial coding.

Adult↗

PubMed2006

Identity state-dependent attentional bias for facial threat in dissociative identity disorder.

Biased attention for threatening stimuli has been associated with many forms of psychopathology. Attention to threatening faces presented below perceptual thresholds was assessed in patients diagnosed with dissociative identity disorder using a pictorial emotional Stroop task. Patients were tested in two different identity states, in one of which they claimed strong awareness of trauma. Attentional bias for social threat proved state-dependent in the patients and deviated from the patterns observed in controls.

Adult↗

PubMed2006

Inter-identity amnesia in dissociative identity disorder: a simulated memory impairment?

BACKGROUND: Although included in the current edition of the DSM, there does not seem to be consensus among mental health professionals regarding the diagnostic status and scientific validity of dissociative identity disorder (DID). This study was aimed at the detection of simulation of inter-identity amnesia in DID. METHOD: A sample of 22 DID patients was included, together with a matched control sample of subjects instructed to simulate inter-identity amnesia, a guessor group that had no knowledge of the stimulus material and a normal control group. A multiple-choice recognition test was included. The rate of incorrect answers was determined. Moreover, the specific simulation strategy used was examined by providing subjects with a range of choices that varied in extent of disagreement with the correct answer and determining whether plausible or implausible answer alternatives were selected. RESULTS: On the recognition test DID patients selected incorrect answers above chance like simulators. Patients thus seem to use their knowledge of the correct answer in determining their given answer. They were not characterized by a well-thought-out simulating behaviour style, as indicated by the differences in selection of specific answer alternatives found between patients and simulators. CONCLUSIONS: DID patients were found not to be characterized by an actual memory retrieval inability, in contrast to their subjective reports. Instead, it is suggested that DID may more accurately be considered a disorder characterized by meta-memory problems, holding incorrect beliefs about their own memory functioning.

Adult↗

PubMed2005

Transfer of newly acquired stimulus valence between identities in dissociative identity disorder (DID).

Patients with Dissociative Identity Disorder (DID) frequently report episodes of interidentity amnesia, that is amnesia for events experienced by other identities. The goal of the present experiment was to test the implicit transfer of trauma-related information between identities in DID. We hypothesized that whereas declarative information may transfer from one identity to another, the emotional connotation of the memory may be dissociated, especially in the case of negative, trauma-related emotional valence. An evaluative conditioning procedure was combined with an affective priming procedure, both performed by different identities. In the evaluative conditioning procedure, previously neutral stimuli come to refer to a negative or positive connotation. The affective priming procedure was used to test the transfer of this acquired valence to an identity reporting interidentity amnesia. Results indicated activation of stimulus valence in the affective priming task, that is transfer of emotional material between identities.

Amnesia↗

PubMed2004

Procedural memory in dissociative identity disorder: when can inter-identity amnesia be truly established?

In a serial reaction time task, procedural memory was examined in Dissociative Identity Disorder (DID). Thirty-one DID patients were tested for inter-identity transfer of procedural learning and their memory performance was compared with 25 normal controls and 25 controls instructed to simulate DID. Results of patients seemed to indicate a pattern of inter-identity amnesia. Simulators, however, were able to mimic a pattern of inter-identity amnesia, rendering the results of patients impossible to interpret as either a pattern of amnesia or a pattern of simulation. It is argued that studies not including DID-simulators or simulation-free memory tasks, should not be taken as evidence for (or against) amnesia in DID.

Amnesia↗

PubMed2003

Interidentity amnesia for neutral, episodic information in dissociative identity disorder.

Interidentity amnesia is considered a hallmark of dissociative identity disorder (DID) in clinical practice. In this study, objective methods of testing episodic memory transfer between identities were used. Tests of both recall (interference paradigm) and recognition were used. A sample of 31 DID patients was included. Additionally, 50 control subjects participated, half functioning as normal controls and the other half simulating interidentity amnesia. Twenty-one patients subjectively reported complete one-way amnesia for the learning episode. However, objectively, neither recall nor recognition scores of patients were different from those of normal controls. It is suggested that clinical models of amnesia in DID may be specified to exclude episodic memory impairments for emotionally neutral material.

Adult↗

PubMed2002

Perceptual and conceptual priming in patients with dissociative identity disorder.

The present study examined implicit memory transfer in patients with dissociative identity disorder (DID). To determine priming impairments in DID, we included both several perceptual priming tasks and a conceptual priming task using neutral material. We tested a large sample of DID patients (n = 31), in addition to 25 controls and 25 DID simulators, comparable on sex, age, and education. Controls replicated conceptual priming results of Vriezen, Moscovitch, and Bellos (1995) by showing that conceptual priming seems to require the formation of domain-specific semantic representations, denoting either sensory or functional object attributes. We extended a study performed by Schacter, Cooper, and Delaney (1990) by demonstrating priming for impossible object using the sensitive priming index of response times. The simulators in the study were not able to simulate interidentity amnesia on the implicit memory tasks employed. Partly in contrast to participants in previous studies, DID patients showed evidence of perceptual priming as well as conceptual priming comparable to that of controls. DID patients thus displayed normal implicit memory performance.

Adult↗