Dispatch-assisted CPR: where are the hold-ups during calls to emergency dispatchers? A preliminary analysis of caller-dispatcher interactions during out-of-hospital cardiac arrest using a novel call transcription technique

BACKGROUND

Survival from out-of-hospital cardiac arrest (OHCA) is dependent on the chain of survival. Early recognition of cardiac arrest and provision of bystander cardiopulmonary resuscitation (CPR) are key determinants of OHCA survival. Emergency medical dispatchers play a key role in cardiac arrest recognition and giving telephone CPR advice. The interaction between caller and dispatcher can influence the time to bystander CPR and quality of resuscitation. We sought to pilot the use of emergency call transcription to audit and evaluate the holdups in performing dispatch-assisted CPR.

METHODS

A retrospective case selection of 50 consecutive suspected OHCA was performed. Audio recordings of calls were downloaded from the emergency medical dispatch centre computer database. All calls were transcribed using proprietary software and voice dialogue was compared with the corresponding stage on the Medical Priority Dispatch System (MPDS). Time to progress through each stage and number of caller-dispatcher interactions were calculated.

RESULTS

Of the 50 downloaded calls, 47 were confirmed cases of OHCA. Call transcription was successfully completed for all OHCA calls. Bystander CPR was performed in 39 (83%) of these. In the remaining cases, the caller decided the patient was beyond help (n = 7) or the caller said that they were physically unable to perform CPR (n = 1). MPDS stages varied substantially in time to completion. Stage 9 (determining if the patient is breathing through airway instructions) took the longest time to complete (median = 59 s, IQR 22-82 s). Stage 11 (giving CPR instructions) also took a relatively longer time to complete compared to the other stages (median = 46 s, IQR 37-75 s). Stage 5 (establishing the patient's age) took the shortest time to complete (median = 5.5s, IQR 3-9s).

CONCLUSION

Transcription of OHCA emergency calls and caller-dispatcher interaction compared to MPDS stage is feasible. Confirming whether a patient is breathing and completing CPR instructions required the longest time and most interactions between caller and dispatcher. Use of call transcription has the potential to identify key factors in caller-dispatcher interaction that could improve time to CPR and further research is warranted in this area.

Behavior matching in multimodal communication is synchronized

A variety of theoretical frameworks predict the resemblance of behaviors between two people engaged in communication, in the form of coordination, mimicry, or alignment. However, little is known about the time course of the behavior matching, even though there is evidence that dyads synchronize oscillatory motions (e.g., postural sway). This study examined the temporal structure of nonoscillatory actions-language, facial, and gestural behaviors-produced during a route communication task. The focus was the temporal relationship between matching behaviors in the interlocutors (e.g., facial behavior in one interlocutor vs. the same facial behavior in the other interlocutor). Cross-recurrence analysis revealed that within each category tested (language, facial, gestural), interlocutors synchronized matching behaviors, at temporal lags short enough to provide imitation of one interlocutor by the other, from one conversational turn to the next. Both social and cognitive variables predicted the degree of temporal organization. These findings suggest that the temporal structure of matching behaviors provides low-level and low-cost resources for human interaction.

Determiner selection in romance languages: evidence from French

Determiner selection requires the retrieval of the noun's syntactic features (e.g., gender) and sometimes of its phonological features. Miozzo and Caramazza (1999) argued that the selection of determiners in Germanic languages is more straightforward than in Romance languages because it is not dependent on the phonological properties of the following word. In the present study, we used the picture-word interference paradigm to investigate the dependency of the determiner on the noun's features in French. In 3 experiments, we found a gender congruency effect at +200 stimulus onset asynchrony (SOA), indicating that participants were slower to produce the name of a picture (determiner + noun) when the picture-word pair was incongruent in gender than when it was congruent. We failed to replicate this effect at 0 SOA, in line with previous studies (Alario & Caramazza, 2002). Our results suggest that the features involved in determiner selection are not language specific but rather are specific to the determiner system.

Grammatical gender in the production of single words: some evidence from Greek

The present study investigated the effect of prior grammatical gender information provided by the production of a bare noun on the production of a syntactically unrelated, gender-inflected color adjective. The target language was Greek. A lexical priming task involving picture naming was employed. Participants saw a series of pictures, some in color and some in black-and-white; they had to name a black-and-white picture with the single noun (prime) and a color picture with the appropriately inflected color adjective (target). Prior gender information was shown to affect subsequent production of gender-marked words. The effect was restricted to nouns of one gender class (masculine) only. The implications of these results for the representation and processing of gender in production are discussed.

When can listeners detect disfluency in spontaneous speech?

Three experiments investigated listeners' ability to detect disfluency in spontaneous speech. All employed gated word recognition with judgments of disfluency for spontaneous utterances containing disfluencies and for three kinds of fluent control utterances from the same six speakers: repetitions of corrected recordings of original disfluent items, spontaneous fluent utterances loosely matched in structure to the disfluent items, and repetitions of those spontaneous fluent items. In Experiment 1, 120 stimuli were word-level gated and presented to 20 subjects for word identification and for judgments on whether the utterance was about to become disfluent. Listeners were unable to predict disfluency reliably. New subjects (N = 20, 43) judged whether the same utterances had already become disfluent at each word gate in Experiment 2 or at each 35 ms gate in Experiment 3. Subjects reliably detected existing disfluencies during the first word gate after the interruption and before they recognized the word. Though more common around disfluencies than at similar points in controls, failures of word identification were not reliably associated with detection. Results are discussed in the light of computational models of disfluency detection.

Limited visual control of the intelligibility of speech in face-to-face dialogue

Speakers are thought to articulate individual words in running speech less carefully whenever additional nonacoustic information can help listeners recognize what is said (Fowler & Housum, 1987; Lieberman, 1963). Comparing single words excerpted from spontaneous dialogues and control tokens of the same words read by the same speakers in lists, Experiment 1 yielded a significant but general effect of visual context: Tokens introducing 71 new entities in dialogues in which participants could see one another's faces were more degraded (less intelligible to 54 naive listeners) than were tokens of the same words from dialogues with sight lines blocked. Loss of clarity was not keyed to moment-to-moment visual behavior. Subjects with clear sight lines looked at each other too rarely to account for the observed effect. Experiment 2 revealed that tokens of 60 words uttered while subjects were looking at each other were significantly less degraded (in length and in intelligibility to 72 subjects) vis-à-vis controls than were spontaneous tokens of the same words produced when subjects were looking elsewhere. Intelligibility loss was mitigated only when listeners looked at speakers. Two separate visual effects are discussed, one of the global availability and the other of the local use of the interlocutor's face.

The unintelligibility of speech to children: effects of referent availability

Speech addressed to children is supposed to be helpfully redundant, but redundant or predictable words addressed to adults tend to lose intelligibility. Word tokens extracted from the spontaneous speech of the parents of 12 children aged 1; 10 to 3; 0 and presented in isolation to adult listeners showed loss of intelligibility when the words were redundant because they had occurred in repetitions of an utterance (Experiment 1) or referred to an entity which was physically present when named (Experiment 2). Though children (N = 64; mean age 3; 5, S.D. 6.1 months) recognized fewer excerpted object names than adults (N = 40), less intelligible tokens appeared to induce child listeners to rely on the word's extra-linguistic context during the recognition process (Experiment 3), much as such tokens normally induce adults to rely on discourse context. It is proposed that interpreting parental utterances with reference to non-verbal context furthers linguistic development.

The unintelligibility of speech to children

Words artificially isolated from twelve parents' speech to their children (aged 1; 10–3; 0) were significantly less intelligible to adult listeners than words originally spoken to an adult. This effect holds for randomly sampled words and, to a lesser extent, for matched pairs. While parents did not adjust the clarity of word tokens to the linguistic naiveté of the child listeners, they did adjust intelligibility inversely to the observed predictability of the sampled words in their sentence contexts, and words to children proved more redundant in this sense. The relationship of these findings to other work on the clarity of motherese is examined and the implications for the study of children's speech perception outlined.