PSYCHOPHYSIOLOGICAL INDICATORS OF PTSD FOLLOWING HURRICANE INIKI: THE MULTI-SENSORY INTERVIEW
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This material is based upon work supported by the National Science Foundation under Grant No. CMS-9632458. Any opinions, findings, and conclusions or recommendations expressed in this material are those of the author(s) and do not necessarily reflect the views of the National Science Foundation.
The authors would also like to acknowledge the significant contributions of the following volunteers who participated in various aspects of this project: Sherry J. Riney, Mary Jo Gorney-Lucero, Ph.D., Ariel Lang, BA, Lynn Basilio, BA, and Josef Ruzek, Ph.D.
The views expressed in this paper are solely those of the author, not necessarily those of the Department of Veterans Affairs. Correspondence concerning this article should be addressed to Kent D. Drescher, Ph.D., Palo Alto Veterans Affairs Medical Center (323E112), 3801 Miranda Ave., Palo Alto, CA 94304.
Physiological arousal is one of the symptoms for post-traumatic stress disorder (PTSD) noted in DSM-III-R (American Psychiatric Association, 1987). The presence of distinct physiological reactions following severe trauma (most notably combat) has been observed for many years. Recent studies with a combat veteran population have demonstrated autonomic reactivity among PTSD subjects in the presence of salient traumatic cues. One major limitation of existing research is that physiological assessments of PTSD arousal symptoms have most frequently been undertaken many years following the traumatic event(s). In addition, nearly all the controlled studies of autonomic arousal in PTSD have used a male combat trauma population.
Several previous studies have used videotaped stimuli to elicit heightened physiological reactivity in combat veterans with PTSD on heart rate (HR), skin conductance (SC), or electromyographic (EMG) measures (Drescher & Abueg, 1991; Foy et al., 1987; Foy et al., 1990; Keane & Kolb, 1989; Malloy et al., 1983). Other labs have found similar changes in autonomic reactivity with combat sounds (Blanchard et al., 1982; Blanchard et al., 1986; Gerardi et al., 1989; Blanchard et al., 1991; Pallmeyer et al., 1986;), and audiotaped individualized trauma scripts (Boudewyns & Hyer, 1990; Orr et al., 1993; Pitman et al., 1987; Pitman et al., 1990; Pitman et al., 1989). Some studies also report baseline HR differences (Pitman et al., 1987; Shalev et al., 1992). Only a few preliminary studies have assessed women with PTSD for the presence of physiological reactivity to salient traumatic cues (Drescher & Abueg, 1991; Kozak et al., 1988a; Kozak et al., 1988b; Hearst et al., 1992).
One of the challenges of research in this area is that time required to develop standardized videotaped trauma cues for a particular disaster may prevent research teams from arriving in the field as quickly as they might like following a disaster. Individualized cue presentations such as those used by Pitman and Orr's lab (1987, 1989, 1990, 1993) can require significant stimulus preparation time for each subject while in the field. Our goal for this project was to assess the array of PTSD symptoms presented by subjects, and to evaluate the usefulness of a structured interview style physiological assessment which would examine PTSD arousal symptoms and which would have clinical relevance for debriefing teams in the immediate aftermath of a natural disaster.
The natural disaster literature has begun to suggest some commonality in the way that disaster victims present over time. Intrusive thoughts and memories of the trauma (DSM-III_R diagnostic category B), for example, seem to be the most frequently reported PTSD symptoms following natural disaster (McFarlane, 1992; Solomon & Canino, 1990; Madakasira & O'Brien, 1987). However, because of their frequency, the presence of these symptoms during the early phase may not predict particularly well the development of chronic PTSD. McFarlane (1988) reported that intrusive memories had a low specificity (63%) for a PTSD diagnosis, i.e., the presence of these symptoms did not predict strongly whether a person had PTSD or not.
Avoidance symptoms (DSM-III-R diagnostic category C)--feelings of numbness, social withdrawal and avoidance of trauma-relevant situations or reminders--tend to be less frequently reported than intrusive symptoms. Solomon and Canino (1990) report that this finding is uniquely apparent during the acute period following a disaster. However, they propose that measurement may be one reason for this finding. They suggest that certain PTSD instruments may underreport the presence of category C and D symptoms. McFarlane (1992) reported that avoidance had no significant relationship, either with exposure variables, or with predicting the development of PTSD. Shalev (1992) noted that in a group of survivors of a terrorist attack, avoidant symptoms tended to develop later than intrusive symptoms, suggesting that avoidance may be a way of coping with the presence of disturbing traumatic memories, a strategy which may be used increasingly over time.
Symptoms of arousal (DSM-III-R diagnostic category D) seem to be the least studied of PTSD symptoms in disaster samples, though increasingly researchers are suggesting that these may have more predictive value in identifying those at high risk for development of chronic PTSD after a trauma. Shalev (1992) notes that McFarlane's (1988) data indicate that arousal symptoms have a much better specificity (94-100%) than the intrusive symptoms.
The present study has two primary purposes: 1) to examine the prevalence of PTSD symptoms and to look at the variation in the pattern of symptoms presented by subjects assessed shortly after a major natural disaster; 2) to assess for physiological arousal symptoms by measuring physiological responses during the administration of a structured debriefing interview, the Multi-Sensory Interview (MSEI).
Subjects were assigned to groups on the basis of their current PTSD diagnostic status as indicated by the CAPS-1 interview. To be included in the Full PTSD symptom group the subject had to meet full diagnostic criteria for PTSD in categories A B, C, D, and E. 47.8 % of subjects met full PTSD criteria and were assigned to this group. The partial PTSD symptom group was defined as meeting full diagnostic criteria for PTSD in category A and E, and full criteria for two of the remaining three categories B, C, or D. 26.1% of subjects were included in this group. The remaining subjects (26.1%) were assigned to the No PTSD symptom group. Table 1 shows the means for demographic variables.
Impact of Events Scale (IES) - (Horowitz, Wilner, & Alvarez, 1979) This is a frequently used 15 item measure of intrusion and avoidance symptoms found in PTSD.
Keane MMPI-2 Scale (Keane, Malloy, & Fairbank, 1984) - This is a 46 item subscale of the MMPI-2 which is used as an indicator of PTSD symptoms. For this study the items were used independently, the entire MMPI was not administered. A cutoff score of 30 is frequently used to indicate PTSD.
Penn Inventory (Hammarberg, 1992) - This is a 26 item questionnaire designed to indicate the presence and severity of PTSD. This scale has been used with other disaster populations. Similar in format to the Beck Depression Inventory, respondents select one of four statements which best describes their current experience.
Dissociative Experiences Scale (Bernstein, & Putnam, 1986) - This is a 28 item scale which measures the degree to which an individual experiences dissociative events. Respondents mark a line indicating the percent of the time (0-100%) which they experience each symptom.
Sensory Exposure Checklist (Abueg, Drescher, Kubaney, 1992) - This is a 20 item index of degree of hurricane exposure which was developed for this study. Respondents use a 5 point scale to indicate the degree of exposure they experienced to each item. Scaling options range from "No exposure" to "Extreme exposure".
Lifetime Trauma Query (LTQ) (Drescher, Abueg, 1992) - The LTQ is a structured interview which assesses for the presence of a variety types of traumatic experiences during childhood, adolescence, and adulthood. Subjects rate the degree of perceived distress for each trauma.
Following the inquiry about the individual sensory domains, and after a baseline period where the subject was instructed to relax as much as possible, each subject was asked to relate their experience of the hurricane in a narrative fashion. The researcher would say: "I just asked you to tell specific parts of your experience of the hurricane. Now I would like you to tell your story of the hurricane in your own words, from start to finish, focusing on the MOST traumatic or upsetting incidents. Take your time and tell me the whole story." HR, SC, and EMG was collected during this entire narrative period. Physiological samples were collected twice per second and averaged into 5 second blocks. SUDS was collected at the conclusion of the narrative.
Examination of the Lifetime Trauma Survey and CAPS-1 data for lifetime experience of PTSD for a trauma prior to the hurricane indicates that 26.1% of this sample experienced met full PTSD criteria for a previous trauma and 13.0% met our definition for partial PTSD symptoms for a previous trauma. 54.2% of subjects reported multiple lifetime traumatic experiences.
Correlational analysis indicated significant correlations between severity of current Category B (re-experiencing) symptoms on the CAPS and Skin Conductance measures of the Multi-Sensory Interview. Correlations were also indicated for total current CAPS severity and the subscales of the IES and the PENN inventory. Correlation matrixes for these and other scales are found in Table 3.
Analysis of Covariance indicates a significant main effect (F=11.5, p=.001) for both current CAPS diagnosis (F=20.3, p=.000) and Lifetime CAPS (F=9.2, p=.005) diagnosis on Skin Conductance (SC) measures for the Narrative portion of the Multi-Sensory Interview when covarying for Exposure (F=17.3, p=.002), and Baseline SC level (F=98.9, p=.000). An examination of the means for each group suggests that the Partial PTSD group had the highest SC levels, followed by the Full PTSD group.
Finally, analysis of variance indicates a main effect (F=5.4, p=.017) for multiple lifetime trauma experiences (F=9.9, p=.007) and gender (F=0.3, p=ns) significantly predicted the overall level of PTSD severity as measured by the CAPS-1 even after controlling for the degree of hurricane exposure (F=0.9, p=ns), and age (F=0.8, p=ns). There was also a significant 2-way interaction effect between the multiple trauma and gender variables (F=4.6, p=.050). Additional analyses indicated a main effect (F=3.74, p=.049) for multiple lifetime trauma experiences (F=5.3, p=.037) and gender (F=1.4, p=ns) for Category B symptoms (reexperiencing) as measured by the CAPS-1 even after controlling for the degree of hurricane exposure (F=0.4, p=ns), and age (F=2.5, p=ns). No group differences were noted for Category C or Category D symptoms.
The finding that psychophysiological variables (skin conductance) were related to level of current PTSD diagnosis replicates and extends previous findings with a new protocol, the multi-sensory interview. Though it is at this point unclear why the partial PTSD subjects have the highest SC responses when describing their trauma experiences from a sensory standpoint, it at the very least is promising and suggests the need for further PTSD psychophysiological field research with disaster populations.
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Sex - Male 25.0% - Female 75.0% Ethnicity - Caucasian 59.1% - Asian/Pacific Islander 31.8% - Filipino 9.1% Marital Status - Single 18.2% - Married 50.0% - Separated 9.1% - Divorced 13.6% - Widowed 9.1%
SCALE MEAN SD ----- ---- -- Keane 12.41 8.38 IES - Intrusion 18.40 4.47 IES - Avoidance 18.10 5.40 Penn 27.27 9.21 Exposure 34.64 11.31 CAPS-Total 49.91 27.03
CAPS CAT B FEEL HEAR SEE SMELL TASTE NARAT CAPS 1.00 CAT B .72** 1.00 FEEL .30 .53* 1.00 HEAR .36 .57* .97** 1.00 SEE .27 .53* .98** .95** 1.00 SMELL .33 .63** .96** .97** .97** 1.00 TASTE .30 .57* .94** .97** .97** .97** 1.00 NARAT .40 .62** .94** .95** .95** .94** .92** 1.00
CAPS AVD INTR KEANE PENN EXP CAPS 1.00 AVD .15 1.00 INTR .47* .55* 1.00 KEANE .45* .34 .33 1.00 PENN .49* -.01 .30 .64** 1.00 EXP .17 .37 .31 -.06 .11 1.00 * - Signif. LE .05 ** - Signif. LE .01 (2-tailed)
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