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Lecture 22 – Psyco 350, B1 Winter, 2011. N. R. Brown. Outline. Memory Issues in PTSD Background Dual-representation Theory (& Data) Holmes, Brewin, & Hennessy, 2003 The Mnemonic Model (& Data). Post-traumatic Stress Disorder: Background. DSM-IV Criterion A .
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Lecture 22 – Psyco 350, B1Winter, 2011 N. R. Brown Psyco 350 Lec #22– Slide 1
Outline • Memory Issues in PTSD • Background • Dual-representation Theory (& Data) Holmes, Brewin, & Hennessy, 2003 • The Mnemonic Model (& Data) Psyco 350 Lec #22– Slide 2
Post-traumatic Stress Disorder:Background Psyco 350 Lec #22– Slide 3
DSM-IV Criterion A The person has been exposed to a traumatic event in which both of the following have been present: (1 – The Event) The person experienced, witnessed, or was confronted with an event or events that involved actual or threatened death or serious injury, or a threat to the physical integrity of self or others (2 – Peritraumatic Reaction) the person's response involved intense fear, helplessness, or horror. Psyco 350 Lec #22– Slide 4
DSM-IV Criteria B-F B. reexperiencing of the traumatic event C. avoidance of stimuli associated w/ trauma and numbing of general responsiveness D. increased arousal symptoms present for more than 1 month clinically significant impairment in social, occupational, or other important areas of functioning Psyco 350 Lec #22– Slide 5
Dual- Representation Theory (DRT) Psyco 350 Lec #22– Slide 6
DRT: Holmes, Brewin, & Hennesy (2004) Two type of event information 1. Verbally Accessible Memory (VAM) “ordinary autobiographical memory” requires “high-level of conscious processing” 2. Situationally Accessible Memory (SAM) “stores sensory information, mostly… in the form of visual images” Psyco 350 Lec #22– Slide 7
DRT: SAM on Its Own SAM Retrieval: triggered by exposure to “relevant” cues accessed automatically Reaction to SAM: re-experience event emotion-laden flashbacks strong affective response Psyco 350 Lec #22– Slide 8
DRT: Further Assumptions VAM blocks SAM: controls & contextualizes SAM-based responses WM-systems & the creation SAMs & VAMS: Verbal WM required for VAMs Visuo-spatial WM required for SAMs Psyco 350 Lec #22– Slide 9
DRT: Implications Creation of PTSD-evoking representations: Dissociative reactions to traumatic event knocks-out WM capacity necessary for VAM creation SAM encoded regardless VAM-less SAMs PTSD symptoms Psyco 350 Lec #22– Slide 10
Testing DRT w/ Dual Task Design General Paradigm: Watch horrific film while engaged in either: (a) spatial task (b) verbal task General Predictions: spatial task knock out SAM reduce PTSD symptoms verbal task knock out VAM increase PTSD symptoms. Psyco 350 Lec #22– Slide 11
The Experiment(s) Participants: Healthy, young adults 20/group Materials: 12.5 min film – actual traffic accidents Instructions: Watch film for later memory test Psyco 350 Lec #22– Slide 12
The Experiment(s) Concurrent Tasks (between-subjects): Control – no concurrent task Visual-spatial inference – tap out a preseficed pattern on buttons Verbal-interference – count backwards by 3s Main DV: # of intrusive memories recalled in 7-day diary Psyco 350 Lec #22– Slide 13
The Experiment(s) Expectation: Counting interferes w/ VAM creation Tapping interferes w/ SAM creation Prediction: # intrusive memories: counting > control > interference Psyco 350 Lec #22– Slide 14
Results: # of Intrusions • As predicated: • tapping < control Psyco 350 Lec #22– Slide 15
Results: # of Intrusions • As predicated: • tapping < control • counting > control Psyco 350 Lec #22– Slide 16
DRT: Discussion DRT correctly predictions intrusion patterns. But: Are these data PTSD-relevant? If so, How do VAM-less SAMs create PTSD? How do VAMs inhibit SAM-trigged responses? PTSD in non-humans? Psyco 350 Lec #22– Slide 17
The Mnemonic “Model” Psyco 350 Lec #22– Slide 18
Rubin, Berntsen, & Klindt-Johansen. (2009) Psychological Review A Memory-based Model of Post-traumatic Stress Disorder: Evaluating Basic Assumptions Underlying PTSD Diagnosis A telling and misleading title. Psyco 350 Lec #22– Slide 19
The “Models” DSM Model Proximal Event: A1 event & A2 reaction Response: Symptoms Mnemonic Model Proximal Event: A1 event & A2 reaction Response: Symptoms Memory for A1& A2 Psyco 350 Lec #22– Slide 20
Support for Mnemonic Position “most direct evidence for ... memory ...as a causal agent is that observation that eliminating or enhancing memory in various ways changes PTSD symptom severity” Psyco 350 Lec #22– Slide 21
Memory & PTSD Amnesia reduces or eliminates PTSD • Organic amnesia – traumatic brain injury • Pharmacologically-induced amnesia • Propranolol treatment reduced PTSD symptoms in emergency room patients (Pitman et al, 2002) • Childhood Amnesia • Before 3: No PTSD • 3-to-7: PTSD symptoms increase w/ age • After 7: PTSD unrelated to age Psyco 350 Lec #22– Slide 22
Memory & PTSD PTSD symptoms , as availability of traumatic memory • Method: correlate Centrality of Event Scale (CES; B&R, 2006, 2007) w/ PTSD symptom. • CES measures importance of traumatic event: • To personal identity • As a turning point • As a reference point • Results: r’s ranging from .35 to .51 Psyco 350 Lec #22– Slide 23
Questions Is the DSM “model” a strawman? What is required to make the mnemonic “model” a model? Does anyone ever consider the material consequences of traumatic events and their relation to PTSD? Psyco 350 Lec #22– Slide 24