Prevalence of Noise Induced Hearing Loss in Indian Air Force Personnel

Background

Noise exposure is an inherent part of duty of the aircrew and maintenance staff in the Indian Air Force (IAF). An audiometric survey of IAF personnel was carried out to analyze the prevalence and severity of noise induced hearing loss (NIHL).

Methods

An audiometric study of 1000 IAF personnel of various trades, age and exposure groups were carried out at an operational base. Age related correction of 5 dB per decade was applied for personnel above SO years of age. Personal factors like smoking, blood group and use of ear defenders were analysed for their effect on the prevalence of NIHL.

Result

The study revealed an overall incidence of NIHL of 22.9 % in the personnel with a higher prevalence among the technical trades (26.18 %) as compared to non technical trades (12.5 %). There was a significant increase in prevalence of hearing loss with duration of exposure with 50.8% of personnel above 30 years of exposure having hearing loss. A higher incidence of hearing loss was observed in personnel of blood group O and smokers whereas use of ear defenders was protective.

Conclusion

The study reveals a significantly increased prevalence of NIHL among the technical trades of the IAF personnel. The deleterious effects of smoking and protective effect of regular use of ear defenders are emphasized.Key Words: Noise induced hearing loss, Smoking, Ear defenders     

Volume-controlled vs no/short-term drainage after axillary lymph node dissection in breast cancer surgery: A meta-analysis

It is unknown whether there are any clinically relevant differences between volume-controlled (<30–50 ml/24 h across trials) vs no/short-term drainage after axillary lymph node dissection in breast cancer surgery on outcomes such as seroma formation, wound infection or length of hospital stay.Randomised controlled trials comparing volume-controlled drainage vs no or short-term drainage after axillary lymph node dissection in breast cancer surgery were identified systematically using Pubmed, EMBASE and The Cochrane library. Trial data were reviewed and extracted independently by two reviewers in a standardised unblinded manner.Six randomised controlled trials which included a total of 561 patients fulfilled our inclusion criteria. Patients randomised to volume-controlled drainage were less likely to develop clinically relevant seromas compared to patients randomised to no/short-term drainage. There was, however, no difference in wound infections between patients treated with volume-controlled drainage and patients with no or short-term drainage. Patients randomised to volume-controlled drainage stayed significantly longer in hospital than patients randomised to no/short-term drainage.Based on available evidence, clinically relevant seromas occur more frequently in patients treated with no/short-term drainage. However, no/short-term drainage after axillary lymph node dissection does not lead to an increase in wound infections and is associated with shorter hospital stay.     

Selective naming (and comprehension) deficits in Alzheimer's disease?

The study addresses the issue of the selective preservation of verbs in Alzheimer's disease (AD). Twenty three AD patients and age-matched controls named pictures of objects and actions and took part in a word-picture verification task. The results for picture naming revealed that both patients and controls were faster and produced more target responses for objects than actions. In the comprehension task, accuracy levels were comparable for nouns and verbs, but response times were longer for verbs. Although patients were more error prone and had longer latencies in both tasks than controls, the only qualitative difference in performance between the groups was in response to trials with semantically related foils in the word-picture verification task. Patients were particularly error prone in this condition. We conclude that the results do not provide support for the notion that verbs are selectively preserved in AD. They also do not provide conclusive evidence for claims that depressed naming and comprehension is (always) due to loss of semantic knowledge or inadequate access to semantic knowledge. Finally, we discuss the findings in relation to comparable investigations in patients with semantic dementia.     

Recall and recognition memory in amnesia: patients with hippocampal, medial temporal, temporal lobe or frontal pathology

The relationship between recall and recognition memory impairments was examined in memory-disordered patients with either hippocampal, medial temporal, more widespread temporal lobe or frontal pathology. The Hirst [Hirst, W., Johnson, M. K., Phelps, E. A., & Volpe, B. T. (1988). More on recognition and recall in amnesics. Journal of Experimental Psychology: Learning, Memory, & Cognition, 14, 758-762] technique for titrating exposure times was used to match recognition memory performance as closely as possible before comparing recall memory scores. Data were available from two different control groups given differing exposure times. Each of the patient groups showed poorer recall memory performance than recognition scores, proportionate to the difference seen in healthy participants. When patients' scores were converted to Z-scores, there was no significant difference between mean Z-recall and Z-recognition scores. When plotted on a scatterplot, the majority of the data-points indicating disproportionately low recall memory scores came from healthy controls or patients with pathology extending into the lateral temporal lobes, rather than from patients with pathology confined to the medial temporal lobes. Patients with atrophy extending into the parahippocampal gyrus (H+) performed worse than patients with atrophy confined to the hippocampi (H-); but, when H- patients were given a shorter exposure time (5s) and compared with H+ at a longer exposure (10s), their performance was virtually identical and did not indicate any disproportionate recall memory impairment in the H- group. Parahippocampal volumes on MRI correlated significantly with both recall and recognition memory. The possibility that findings were confounded by inter-stimulus artefacts was examined and rejected. These findings argue against the view that hippocampal amnesia or memory disorders in general are typically characterised by a disproportionate impairment in recall memory. Disproportionate recall memory impairment has been observed in a number of published cases, and the reason for the varying pattern obtained across hippocampal patients requires further examination.     

Requests for 692 transfers to an academic level I trauma center: implications of the emergency medical treatment and active labor act

BACKGROUND: The Emergency Medical Treatment and Active Labor Act (EMTALA) effectively requires Level I trauma centers (TC) to accept all transfers for a higher level of care if capacity exists. We hypothesized that EMTALA would burden a Level I TC by a selective referral of a poor payer mix of primarily nonoperative patients. METHODS: All transfer calls (December 2003 and September 2005) to our Level I TC are handled by a dedicated transfer center. Calls were reviewed for age, surgical service requested, and outcome of request. The trauma registry was queried to compare Injury Severity Scale (ISS) score, hospital stay (LOS), operations, mortality, and payer status for transfer and primary catchment patients. RESULTS: In all, 821 calls were received; 77 calls were cancelled by the referring hospital and 52 were for consultation only. Of the 692 transfer requests, 534 (77%) were accepted, 134 (19%) were denied for no capacity, and only 24 (4%) were declined by TC as not clinically indicated. Transferred patients were younger (32.0 +/- 1.49 versus 38.9 +/- 0.51, p < 0.05), had similar ISS scores (13.6 +/- 0.62 versus 13.7 +/- 0.26) and LOS (7.0 +/- 0.70 versus 7.4 +/- 0.25), but were somewhat more likely to require an operation than direct admissions (58% versus 51%, p < 0.05). Although trauma (24%) and neurosurgery (24%) were the most commonly requested services, followed by orthopedics (20%), orthopedics accounted for 60% of operations on transferred patients compared with 10% to 13% for trauma and neurosurgery (mostly spine). There was no difference in the payer status of transfer and direct admit patients. CONCLUSIONS: Contrary to our assumptions, EMTALA patients had an identical payer mix and similar operative need compared with our primary catchment patients. They do represent a large additional patient load (20% of admissions) and differentially impact specialists, mostly operative for orthopedics and complex nonoperative care for trauma and neurosurgery. These data suggest that the primary motivations for transfer are specialist availability and complexity of care rather than financial concerns. As TCs provide backup specialty call coverage for a wide geographic area, this further supports the need for trauma systems development.     

Meeting oxygen needs in Africa: an options analysis from the?Gambia

Objective

To compare oxygen supply options for health facilities in the Gambia and develop a decision-making algorithm for choosing oxygen delivery systems in Africa and the rest of the developing world.

Methods

Oxygen cylinders and concentrators were compared in terms of functionality and cost. Interviews with key informants using locally developed and adapted WHO instruments, operational assessments, cost-modelling and cost measurements were undertaken to determine whether oxygen cylinders or concentrators were the better choice. An algorithm and a software tool to guide the choice of oxygen delivery system were constructed.

Findings

In the Gambia, oxygen concentrators have significant advantages compared to cylinders where power is reliable; in other settings, cylinders are preferable as long as transporting them is feasible. Cylinder costs are greatly influenced by leakage, which is common, whereas concentrator costs are affected by the cost of power far more than by capital costs. Only two of 12 facilities in the Gambia were found suitable for concentrators; at the remaining 10 facilities, cylinders were the better option.

Conclusion

Neither concentrators nor cylinders are well suited to every situation, but a simple options assessment can determine which is better in each setting. Nationally this would result in improved supply and lower costs by comparison with conventional cylinders alone, although ensuring a reliable supply would remain a challenge. The decision algorithm and software tool designed for the Gambia could be applied in other developing countries.     

FDG-PET findings in the Wernicke-Korsakoff syndrome

This study reports FDG-PET findings in Wernicke-Korsakoff patients. Twelve patients suffering amnesia arising from the Korsakoff syndrome were compared with 10 control subjects without alcohol-related disability. Subjects received [¹⁸F]-fluorodeoxyglucose (FDG-PET) imaging as well as neuropsychological assessment and high-resolution MR imaging with volumetric analysis. Volumetric MRI analysis had revealed thalamic and mamillary body atrophy in the patient group as well as frontal lobe atrophy with relative sparing of medial temporal lobe structures. Differences in regional metabolism were identified using complementary region of interest (ROI) and statistical parametric mapping (SPM) approaches employing either absolute methods or a reference region approach to increase statistical power. In general, we found relative hypermetabolism in white matter and hypometabolism in subcortical grey matter in Korsakoff patients. When FDG uptake ratios were examined with occipital lobe metabolism as covariate reference region, Korsakoff patients showed widespread bilateral white matter hypermetabolism on both SPM and ROI analysis. When white matter metabolism was the reference covariate, Korsakoff patients showed relative hypometabolism in the diencephalic grey matter, consistent with their known underlying neuropathology, and medial temporal and retrosplenial hypometabolism, interpreted as secondary metabolic effects within the diencephalic-limbic memory circuits. There was also evidence of a variable degree of more general frontotemporal neocortical hypometabolism on some, but not all, analyses.