47 at scene of RG7422 nmr injury and .52 in hospital with the items. Relationship between the CCI and stress responses The Cronbach’s alpha for IES was .94 (total score), .93 (intrusion) and .90 (avoidance). For the PTSS-10 the Cronbach’s alpha was .92. The correlations between the CCI and measures of posttraumatic stress (Table ​(Table3)3) were all moderately high (r = .32-.54) and highly significant (p < .001). Table 3 Correlations between the CCI subscales and stress responses

Discussion The CCI showed a two-factor Inhibitors,research,lifescience,medical structure of perception of the incident (6 items) and dissociation (2 items) with good internal consistency both at the scene of the injury and in the hospital. Even though there is a two-factor structure, the high Cronbach’s alpha for all eight items indicates that a sum score of the CCI also can be used. The main contribution of the new instrument is the assessment of peritraumatic sensory perception. The factor analysis showed that dissociation was a Inhibitors,research,lifescience,medical separate factor, correlating with the perception factor (at scene of injury .42 and in hospital .46). Inhibitors,research,lifescience,medical ln this study, the level of fear however, loaded on the same factor as the perception items. It remains to be seen whether perception will be a stronger predictor

for later PTS. The explained variance is high both at the scene of injury (61%) and in the hospital (65%). This means that about two-thirds of perceived threat is explained Inhibitors,research,lifescience,medical by the CCI and the instrument appears to be valid. The internal

consistency of the CCI was somewhat lower compared to the IES and PTSS-10. Examining the association between the CCI score and the scores on IES and PTSS-10 was important to see whether the instruments assessed different phenomena. Since the correlation was < .7 the new instrument (CCI) can give further contribution when predicting posttraumatic stress symptoms. Among the sensory impression scores, pain had the highest Inhibitors,research,lifescience,medical mean score. Fear decreased the most from the scene of the injury to the hospital. Even though mean scores for the sensory impressions were low, both the total scale and the factor perceptions showed strong internal consistency. This indicates that, in addition to dissociation, sensory impressions (together with fear and feeling emotionally stuck) are important to screen for when identifying who is at risk of developing clinically significant posttraumatic stress. Pain may both be a sensory perception these as well as a psychological reaction and related to fear; this may explain the strong impact in this findings. It is possible that an activated stress response makes a person more vulnerable to sensory impressions. Therefore, the problem may involve a combination of high levels of sensory impact and heightened vulnerability to sensory impressions. In clinical work a screening of sensory impressions may also indicate which specific sensory channel (e.g. visual or auditory) to address in treatment of posttraumatic stress.