The Cholecystectomy As A Day Case (CAAD) Score: A Validated Score of Preoperative Predictors of Successful Day-Case Cholecystectomy Using the CholeS Data Set

Background Day-case surgery is associated with significant patient and cost benefits. However, only 43% of cholecystectomy patients are discharged home the same day. One hypothesis is day-case cholecystectomy rates, defined as patients discharged the same day as their operation, may be improved by better assessment of patients using standard preoperative variables. Methods Data were extracted from a prospectively collected data set of cholecystectomy patients from 166 UK and Irish hospitals (CholeS). Cholecystectomies performed as elective procedures were divided into main (75%) and validation (25%) data sets. Preoperative predictors were identified, and a risk score of failed day case was devised using multivariate logistic regression. Receiver operating curve analysis was used to validate the score in the validation data set. Results Of the 7426 elective cholecystectomies performed, 49% of these were discharged home the same day. Same-day discharge following cholecystectomy was less likely with older patients (OR 0.18, 95% CI 0.15–0.23), higher ASA scores (OR 0.19, 95% CI 0.15–0.23), complicated cholelithiasis (OR 0.38, 95% CI 0.31 to 0.48), male gender (OR 0.66, 95% CI 0.58–0.74), previous acute gallstone-related admissions (OR 0.54, 95% CI 0.48–0.60) and preoperative endoscopic intervention (OR 0.40, 95% CI 0.34–0.47). The CAAD score was developed using these variables. When applied to the validation subgroup, a CAAD score of ≤5 was associated with 80.8% successful day-case cholecystectomy compared with 19.2% associated with a CAAD score >5 (p < 0.001). Conclusions The CAAD score which utilises data readily available from clinic letters and electronic sources can predict same-day discharges following cholecystectomy

Primate brains in the wild: the sensory bases for social interactions.

Each organism in the animal kingdom has evolved to detect and process a specific set of stimuli in its environment. Studies of an animal's socioecology can help us to identify these stimuli, as well as the natural behavioural responses that they evoke and control. Primates are no exception, but many of our specializations are in the social domain. How did the human brain come to be so exquisitely tuned to social interactions? Only a comparative approach will provide the answer. Behavioural studies are shedding light on the sensory bases for non-human primate social interactions, and data from these studies are paving the way for investigations into the neural bases of sociality

Monkeys match the number of voices they hear to the number of faces they see

SummaryConvergent evidence demonstrates that adult humans possess numerical representations that are independent of language [1–6]. Human infants and nonhuman animals can also make purely numerical discriminations, implicating both developmental and evolutionary bases for adult humans’ language-independent representations of number [7, 8]. Recent evidence suggests that the nonverbal representations of number held by human adults are not constrained by the sensory modality in which they were perceived [9]. Previous studies, however, have yielded conflicting results concerning whether the number representations held by nonhuman animals and human infants are tied to the modality in which they were established [10–15]. Here, we report that untrained monkeys preferentially looked at a dynamic video display depicting the number of conspecifics that matched the number of vocalizations they heard. These findings suggest that number representations held by monkeys, like those held by adult humans, are unfettered by stimulus modality

Multisensory integration of looming signals by rhesus monkeys.

AbstractLooming objects produce ecologically important signals that can be perceived in both the visual and auditory domains. Using a preferential looking technique with looming and receding visual and auditory stimuli, we examined the multisensory integration of looming stimuli by rhesus monkeys. We found a strong attentional preference for coincident visual and auditory looming but no analogous preference for coincident stimulus recession. Consistent with previous findings, the effect occurred only with tonal stimuli and not with broadband noise. The results suggest an evolved capacity to integrate multisensory looming objects

Voice processing in human and non-human primates

Humans share with non-human primates a number of voice perception abilities of crucial importance in social interactions, such as the ability to identify a conspecific individual from its vocalizations. Speech perception is likely to have evolved in our ancestors on the basis of pre-existing neural mechanisms involved in extracting behaviourally relevant information from conspecific vocalizations (CVs). Studying the neural bases of voice perception in primates thus not only has the potential to shed light on cerebral mechanisms that may be—unlike those involved in speech perception—directly homologous between species, but also has direct implications for our understanding of how speech appeared in humans. In this comparative review, we focus on behavioural and neurobiological evidence relative to two issues central to voice perception in human and non-human primates: (i) are CVs ‘special’, i.e. are they analysed using dedicated cerebral mechanisms not used for other sound categories, and (ii) to what extent and using what neural mechanisms do primates identify conspecific individuals from their vocalizations

Non-invasive documentation of primate voice production using electroglottography

Electroglottography (EGG) is a low-cost, non-invasive method for documenting laryngeal sound production during vocalization. The EGG signal represents relative vocal-fold contact area and thus delivers physiological evidence of vocal-fold vibration. While the method has received much attention in human voice research over the last five decades, it has seen very little application in other mammals. Here, we give a concise overview of mammalian vocal production principles. We explain how mammalian voice production physiology and the dynamics of vocal-fold vibration can be documented qualitatively and quantitatively with EGG, and we summarize and discuss key issues from research with humans. Finally, we review the limited number of studies applying EGG to non-human mammals, both in vivo and in vitro. The potential of EGG for non-invasive assessment of non-human primate vocalization is demonstrated with novel in vivo data of Cebus albifrons and Ateles chamek vocalization. These examples illustrate the great potential of EGG as a new minimally invasive tool in primate research, which can provide important insight into the ‘black box’ that is vocal production. A better understanding of vocal-fold vibration across a range of taxa can provide us with a deeper understanding of several important elements of speech evolution, such as the universality of vocal production mechanisms, the independence of source and filter, the evolution of vocal control, and the relevance of non-linear phenomena