Identification of delirium and dementia in older medical inpatients in Tanzania: A comparison of screening and diagnostic methods.

BACKGROUND: In sub-Saharan Africa, there are no validated screening tools for delirium in older adults. This study assesses clinical utility of two instruments, the IDEA cognitive screen and the Confusion Assessment Method (CAM) for identification of delirium in older adults admitted to medical wards of a tertiary referral hospital in Tanzania. METHOD: The IDEA cognitive screen and CAM were administered to a consecutive cohort of older individuals on admission to Kilimanjaro Christian Medical Centre using a blinded protocol. Consensus diagnosis for delirium was established against DSM-5 criteria and dementia by DSM-IV criteria. RESULTS: Of 507 admission assessments, 95 (18.7%) had DSM-5 delirium and 95 (18.7%) had DSM-IV dementia (33 (6.5%) delirium superimposed on dementia). The CAM and IDEA cognitive screen had very good diagnostic accuracy for delirium (AUROC curve 0.94 and 0.87 respectively). However, a number of participants (10.5% and 16.4% respectively) were unable to complete these screening assessments due to reduced consciousness, or other causes of reduced verbal response and were excluded from this analysis; many of whom met DSM-5 criteria for delirium. Secondary analysis suggests that selected cognitive and observational items from the CAM and IDEA cognitive screen may be as effective as the full screening tools in identifying delirium even in unresponsive patients. CONCLUSION: Both instruments appeared useful for delirium screening in this inpatient setting, but had significant limitations. The combination of assessment items identified may form the basis of a brief, simple delirium screening tool suitable for use by non-specialist clinicians. Further development work is needed.

A cross-sectional study of mental health in UK veterinary undergraduates.

Wellbeing (positive mental health) and mental ill-health of veterinary students from a single UK school were quantified using validated psychological scales. Attitudes towards mental ill-health and suicide were also assessed. Results were compared with published data from the UK general population and veterinary profession. Of the total student population (N=1068), 509 (48 per cent) completed a questionnaire. Just over half (54 per cent) of the respondents had ever experienced mental ill-health, with the majority reporting a first occurrence before veterinary school. Student wellbeing was significantly poorer (p<0.0001) than general population estimates, but not significantly different (p=0.2) from veterinary profession estimates. Degree of mental distress in students was significantly higher than in the general population (p<0.0001). Despite the majority (94 per cent) agreeing that 'Anyone can suffer from mental health problems', students were significantly more likely than members of the general population to agree that 'If I were suffering from mental health problems, I wouldn't want people knowing about it' (p<0.0001). Students were more likely to have thought about suicide, but less likely to have made an attempt (p<0.001; p=0.005), than members of the general population. The possibility of non-response bias must be considered when interpreting findings. However, strong similarities between results from this study population and the UK veterinary profession, as well as other veterinary student populations internationally, suggest no substantial school-level bias.

Field studies on animal trypanosomiasis in Mozambique. I. Effectiveness of the prophylactic drugs isometamidium chloride and pyrithidium bromide.

The efficacy of the trypanocides Samorin and Prothidium to protect beef cattle in areas of different trypanosome challenge was studied in Muabsa, Mozambique during an 18 month period. The performance of two groups of 1.5- to 3-year old bulls was observed, the first group in an area of high tsetse density, the second in an area of low to medium tsetse density. Glossina morsitans and G. pallidipes were present and their respective densities were determined using standard fly rounds, a mobile electric screen and biconical traps. The trypanosome challenge was determined using parameters of tsetse density and infection rates; the trypanosome risk was determined by Berenil Indices in both groups of animals. The Berenil Indices in the two study areas were not significantly different despite a great difference in apparent densities of the tsetse flies. The period of protection afforded by Samorin and Prothidium was similar in both areas which would appear to indicate that the tsetse density had no apparent effect on the degree of challenge. Samorin gave a slightly better protection than Prothidium as shown by a lower frequency of infections as well as higher packed cell volumes. There was no difference in growth rates between the treatment groups and study areas during the entire study period. It was concluded that in the study area Samorin usage is preferable to that of Prothidium. Tsetse densities obtained from standard fly rounds were found unsatisfactory in assessing the challenge, possibly because this method does not sample all components of the population. The Berenil Index, however, was found to be a useful indicator of trypanosome risk and thus frequency of treatment required.

Temporal effects of hemodialysis on measures of neural efficiency.

The short-term effects of hemodialysis on the integrity of the central nervous system (CNS) were examined. Evoked potentials (EP) and performance on five neuropsychologic tests were obtained from six patients undergoing maintenance hemodialysis. Measurements were taken 1, 24, 42, and 66b hours following dialysis. A highly consistent relationship between time since dialysis and EP latency was found. EP latencies tended to decrease during the 1-hour and the 24-hour recording sessions (compared to predialysis recordings), the shortest latencies typically occurring during the 24-hour period, then increasing steadily during the 42-hour and 66-hour intervals. EP amplitude was largest 1 hour after dialysis, then decreased progressively with time since dialysis. Performance on two tests of visual-motor speed and accuracy was best 24 hours after dialysis. The results indicate that there are consistent and measurable changes in the responsivity of the CNS which are related to time since dialysis.

Visual and somatosensory evoked potentials characteristics of patients undergoing hemodialysis and kidney transplantation.

The effects of prolonged hemodialysis and kidney transplantation on visual and somatosensory evoked potentials and EEG frequency were assessed. Significant changes were found in both amplitude and latency characteristics of evoked potentials recorded from eight hemodialysis patients. Their evoked potentials tended to be of longer latency and larger amplitude when compared to responses of an age-matched control group. This was true for visual and somatosensory responses recorded from several scalp locations. A correlational analysis revealed no consistent relationship between blood chemistries and evoked potential characteristics. EEG power spectral analysis showed that the dominant frequency of five of the eight dialysis patients was in the 8-10 c/sec range. Two other patients demonstrated EEG frequencies which were scattered across the 3-12 c/sec range while for another subject the dominant frequency was 7-8 c/sec. The evoked potential latencies and amplitudes of patients with successful kidney transplant tended to return to the normal range and their predominant EEG frequency increased to around 10 c/sec. A depression of function in those neural systems underlying the visual and somatosensory modalities, along with a reduction in the cortical suppression of afferent stimulation normally exerted by the thalamic reticular system and the basal ganglia were postulated to account for the reported findings.

Sensory, perceptual, motor and cognitive functioning and subjective reports following oral administration of delta9-tetrahydrocannabinol.

Three dose levels, 0.2, 0.4, and 0.6 mg/kg, of delta9-tetrahydrocannabinol (THC) and a placebo were orally administered to 10 frequent and 10 occasional marijuana users. Following ingestion of each dose and the placebo, objective tests selected from a battery of sensory and perceptual motor tests routinely used to evaluate cerebral dysfunction in hospitalized patients were administered. The influence of delta9-THC on proficiency and variability of performance was minimal. However, when individual test scores and variabilities were combined and converted to standard scores, allowing for analysis of overall performance, THC had a small but consistent detrimental effect on both proficiency and variability of performance. In contrast, THC exerted profound effects on the subjective experiences of the volunteers as assessed by the Subjective Drug Effects Questionnaire. Subjective changes in mood, feeling, perception and somatic sensations were reported by all subjects but were more pronounced in the occasional user group. It was proposed that the small impairment noted in objective test performance after ingestion of delta9-THC as contrasted to the large effects on subjective responses suggests that the principal effects of marijuana are on the autonomic nervous system rather than on higher cortical functions.

Sustained ingestion of delta 9-tetrahydrocannabinol and the operant behavior of stump-tailed macaques.

Three stump-tailed macaques were trained to press a lever for liquid reinforcement on a tandem schedule which required the animal to delay responding for at least 30 sec after each reinforcer. If the animal responded during that interval, a clock was reset thus re-establishing the delay requirement. If he delayed responding appropriately, the monkey was shifted to a fixed-interval schedule of 135 sec duration. The FI component was terminated with a drop of flavored liquid at which point the delay requirement began anew. Following a stable baseline performance, two monkeys received 2 mg/kg of THC orally every third day for 90 days with the placebo administered on intervening days. The third animal received the placebo throughout testing. Each monkey's performance was described in terms of response rate and response patterning between reinforcers. Despite the sustained ingestion of THC neither animal showed appreciable change in test behavior attributable to tolerance to the drug. Although the drug continued to have a powerful effect throughout testing on the days it was administered, there was no evidence of any consistent or cumulative drug effect on placebo-day performance.