A case-control study examining inconsistencies in pain management following fractured neck of femur: an inferior analgesia for the cognitively impaired.

Previous research suggests individuals who suffer from cognitive impairment are less able to vocalise pain than the rest of the cognitively-intact population. This feature of cognitive impairment may be leading to a chronic underdetection of pain as current assessment tools strongly rely on the participation of the patient. To explore inconsistencies in pain management within the acute setting, we conducted a retrospective assessment of 224 patients presenting with fractured neck of femur at a large teaching hospital's accident and emergency (A&E) department between 2 June 2011 and 2 June 2012. These patients were split into either a cognitively-impaired or cognitively-intact cohort based on their Abbreviated Mental Test Scores. Patients with cognitive impairment, on average, received a weaker level of analgesia than individuals without impairment both in the ambulance and in A&E. In the ambulance, 45% of cognitively-impaired patients were prescribed no pain relief compared with just 8% of those individuals who remain cognitively intact. After arrival at A&E, these inconsistencies continued with 69% of the cognitively-intact cohort receiving the strongest opioid analgesia compared with just 37% of the cognitively-impaired cohort. The cognitively-impaired cohort would also wait on average an hour longer before receiving this initial pain relief. We believe that these differences stem from cognitively-impaired patients being unable to vocalise their pain through traditional assessment methods. This work discusses the potential development or adoption of a tool which can be applied in the acute setting and relies less on vocalisation but more on the objective features of pain, so making it applicable to cognitively-impaired individuals.

Detectability gradients as a function of target location.

We examined the ability to detect a specified visual pattern (a target) in a randomly selected location when it was briefly presented with 11 other spatially distributed nontarget patterns and also when it was presented by itself for the same duration (50 msec) on a background of visual noise. Two experiments were designed to measure target detectability as a function of its location in the visual field where all possible target locations were equidistant from the fovea. A right visual field detection superiority was obtained in both experiments. In addition, highly significant detectability differences were observed within the right and left visual fields in both experiments. The origin of these detectability differences are interpreted in terms of parallel and serial processing mechanisms.

Detectability as a function of target location: effects of spatial configuration.

Marked differences in detectability as a function of spatial location, a "detectability gradient," are observed when subjects are required to detect a briefly exposed target pattern of uncertain location in the presence of a number of nontarget patterns. Target detectability also is inversely related to the number of nontarget patterns which are present in this search paradigm. These previous findings provide strong evidence for a serial process in which increasing probability of error occurs during a scan of a rapidly degrading neural representation of the visual image following a brief exposure to the stimuli. It is not yet established whether this scan is attentional or perceptual in nature. The present experiments test the hypothesis of an attentional scan by presenting the target and nontarget patterns in spatially segregated groups. If the scan is attentional, then target detectability under these circumstances would be expected to exhibit the characteristic phenomenon of "group processing"--a close clustering of detection performance for targets located within a group and large differences in detectability across groups. As no evidence for group processing was observed, the results fail to support the view that the scan is attentional in nature but are fully consistent with a nonattentional scan.

Target detection in one visual field in the presence or absence of stimuli in the contralateral field by right- and left-handed subjects.

Marked differences in detectability are observed as a function of retinal locus when subjects are required to find a briefly exposed target pattern of uncertain location in the presence of a number of discriminably different nontarget patterns. Our previous studies using this search paradigm have attributed these detectability differences, and the right visual field detectability superiority associated with them, to a serial (scanning) mechanism which tends to examine stimuli in the right field earlier than those in the left. The present experiment, performed on large groups of right- and left-handed subjects, was designed to test the hypothesis that there are two independent serial processors, one in each hemisphere--an hypothesis which might account for the differences in detectability within and between the two half-fields in terms of hemispheric processing differences. The results are inconsistent with the dual independent serial processor hypothesis but are fully consistent with a single serial processor, a scanning mechanism, which has access to the information presented to both visual half-fields.

Visual detectability gradients: the effect of distractors in contralateral field.

A number of studies involving recognition of tachistoscopically presented words have reported that the typical right visual field performance superiority associated with linguistic stimuli is enhanced by bilateral presentations (simultaneous stimuli in both visual half-fields) compared to unilateral presentations (stimuli in only one half-field on a trial). We have reported the same phenomenon, however, using visual spatial patterns in a search paradigm (E. W. Yund, R. Efron, & D. R. Nichols, 1990c. Brain and Cognition, 12, 117-127) and have accounted for it in terms of the operating characteristics of a visual scanning mechanism which serially examines a decaying neural representation of the stimuli. In the present experiment we attempted to exploit these operating characteristics to influence this difference between unilateral and bilateral presentations. The results not only are consistent with the assumptions of the scanning hypothesis but they also provide new information pertinent to the operating characteristics of this mechanism.

Serial processing of visual spatial patterns in a search paradigm.

Previous experiments in this laboratory employing a search paradigm have found highly significant differences in the detectability of a briefly exposed target pattern as a function of the spatial location of the target when it is presented simultaneously with a number of discriminably different nontarget patterns. These detectability differences, at loci equidistant from the fovea, could not be accounted for by any known variation in retinal spatial resolution or by differential lateral masking effects of the target by nearby nontarget patterns. These observations led to the hypothesis that the target in these experiments was detected by a serial mechanism which "scanned" a persisting but rapidly degrading neural representation of the visual scene with increasing detection failures the later in time the scan processed the location occupied by the target. If this hypothesis is correct, then target detectability should vary inversely with the number of stimuli which must be examined. The present experiment confirmed this expectation. A mathematical model of such a serial scanning process also predicts other, less obvious, effects on target detectability which were observed when the number of nontarget patterns was changed.

Detectability as a function of spatial location: effects of selective attention.

In a series of previous reports we have described differences in detectability of a target in a background of nontarget patterns as a function of its spatial location. These differences, referred to as a "detectability gradient," have been attributed to target detection accomplished by a serial processing mechanism--a scan. The mathematical model of such a mechanism, developed in the previous report, is equally applicable to a series of attentional shifts or to a perceptual, i.e., a preattentive, mechanism. The present experiments were designed to test the hypothesis that this scan is attentional in nature. The results provide additional evidence for the scanning hypothesis but do not support the view that this scan represents a series of attentional shifts.

Scanning the visual field without eye movements--a sex difference.

Subjects identified the location of a briefly exposed target pattern in the presence of five other patterns. Right-handed females, but not males, exhibited a significantly higher error rate in correctly localizing the target pattern when it was in the left visual field, particularly for the left parafoveal region. This unexpected distribution of errors as a function of target location can be accounted for by a sequential (serial) mechanism which scans the visual field. Since the exposure time was too brief for eye movements to have occurred, the results must reflect an internal scan of the neural representation of the information retained in the visual system following the brief stimulus presentation.

Head and neck manifestations of tularemia.

Tularemia is a relatively uncommon infectious cause of cervical lymphadenopathy. The records were studied of 81 patients hospitalized in western Arkansas with the diagnosis of tularemia over the period of 1970 to 1980. Fourteen cases (17%) had symptoms or findings referable to the head and neck at some time during the disease. Delay in treatment was prolonged in some cases by failure to consider tularemia as a possible diagnosis. The pertinent epidemiology, pathogenesis, clinical manifestations and treatment are briefly reviewed.