Investing in life saving vaccines to guarantee life of future generations in Africa.

The World Health Organization's Regional Offices for Africa and for the Eastern Mediterranean in conjunction with the African Union and the Government of Ethiopia hosted a ministerial conference on immunization in Africa from 24 to 25 February 2016 in Addis Ababa, Ethiopia under the theme "towards universal immunization coverage as a cornerstone for health and development in Africa". The conference brought together African leaders - including health and finance ministers, and parliamentarians thus creating a powerful platform for governments to demonstrate their commitment to advancing universal access to immunization on the continent in line with the Global Vaccine Action Plan. The event also brought together advocates, technical experts, policymakers, partner agencies, donors and journalists to examine how best to drive forward immunization across Africa, ensuring every child has access to the vaccines they need. Key points highlighted throughout conference were: universal access to immunization is at the forefront of enabling Africa to reach its full potential - by improving health, driving economic growth and empowering future generations; it is one of the most cost-effective solutions in global health, with clear benefits for health and development; and immunization brings economic benefits too, reducing health care costs and increasing productivity. At the close of the conference, 46 African countries signed a historic ministerial declaration on "Universal Access to Immunization as a Cornerstone for Health and Development in Africa" signaling fierce determination among African leaders to secure the health and prosperity of their societies through immunization.

Streptokinase in acute stroke: effect on reperfusion and recanalization. Australian Streptokinase Trial Study Group.

The Australian Streptokinase Trial was a randomized, double-blind, placebo-controlled trial, in which streptokinase (SK, 1.5 million IU I.V.) was given within 4 hours of stroke onset. In a subset of 37 patients, 99mTc-labeled D,L-hexamethylpropylene amine oxime single-photon emission computed tomography (SPECT) and/or transcranial Doppler (TCD) studies were performed before and after therapy to test the hypothesis that SK may improve the hemodynamic measures of reperfusion/recanalization rates (TCD parameter) within 24 hours. Eighteen patients received SK and 19 placebo. Baseline characteristics were similar in both groups, and there were no differences in clinical outcomes assessed at 3 months after stroke. Although there was no increase in the group mean perfusion defect or volume on SPECT after thrombolytic therapy, a larger number of patients demonstrating the combined end point of reperfusion or recanalization was seen in the SK group (13/14, 93%) than in the placebo group (7/14, 50%; p = 0.01). Although SK given within 4 hours of acute ischemic stroke appears to improve arterial patency/tissue reperfusion, this effect is neither early nor extensive enough to influence overall clinical outcome.

Cross-modality matching and the loudness growth function for click stimuli.

Loudness-intensity functions for click stimuli were obtained from 30 adult listeners having normal (n = 10), flat (n = 10), or sloping (n = 10) high-frequency cochlear hearing loss configurations. The procedure of cross-modality matching (CMM) between loudness and perceived line length [R. P. Hellman and C. H. Meiselman, J. Speech Hear. Res. 31, 605-615 (1988); J. Acoust. Soc. Am. 88, 2596-2606 (1990); J. Acoust. Soc. Am. 93, 966-975 (1993)] was used to validate their loudness growth functions. Mean group loudness exponents were similar to those reported in recent investigations that utilized pure tone stimuli, further supporting the validity and reliability of the CMM task as an estimate of the loudness growth function. The results also suggest that the mean loudness function for clicks is similar to the function obtained with tonal stimuli at least for listeners with moderately impaired hearing or better. Moreover, CMM produced less variability than the more conventional psychophysical methods of magnitude estimation and production for the groups with cochlear hearing loss. Toward direct application of the CMM technique, in lieu of absolute exponential slope values, the individually determined loudness growth function over a range of intensities should be compared to the normal mean functions for calculations of deviations.

The relationship between loudness intensity functions and the click-ABR wave V latency.

OBJECTIVE: To assess the relationship of loudness growth and the click-evoked auditory brain stem response (ABR) wave V latency-intensity function (LIF) in listeners with normal hearing or cochlear hearing loss. The effect of hearing loss configuration on the intensity functions was also examined. DESIGN: Behavioral and electrophysiological intensity functions were obtained using click stimuli of comparable intensities in listeners with normal hearing (Group I; n = 10), and cochlear hearing loss of flat (Group II; n = 10) or sloping (Group III; n = 10) configurations. Individual intensity functions were obtained from measures of loudness growth using the psychophysical methods of absolute magnitude estimation and production of loudness (geometrically averaged to provide the measured loudness function), and from the wave V latency measures of the ABR. RESULTS: Slope analyses for the behavioral and electrophysiological intensity functions were separately performed by group. The loudness growth functions for the groups with cochlear hearing loss approximated the normal function at high intensities, with overall slope values consistent with those reported from previous psychophysical research. The ABR wave V LIF for the group with a flat configuration of cochlear hearing loss approximated the normal function at high intensities, and was displaced parallel to the normal function for the group with sloping configuration. The relationship between the behavioral and electrophysiological intensity functions was examined at individual intensities across the range of the functions for each subject. A significant relationship was obtained between loudness and the ABR wave V LIFs for the groups with normal hearing and flat configuration of cochlear hearing loss; the association was not significant (p = 0.10) for the group with a sloping configuration of cochlear hearing loss. CONCLUSION: The results of this study established a relationship between loudness and the ABR wave V latency for listeners with normal hearing, and flat cochlear hearing loss. In listeners with a sloping configuration of cochlear hearing loss, the relationship was not significant. This suggests that the click-evoked ABR may be used to estimate loudness growth at least for individuals with normal hearing and those with a flat configuration of cochlear hearing loss. Predictive equations were derived to estimate loudness growth for these groups. The use of frequency-specific stimuli may provide more precise information on the nature of the relationship between loudness growth and the ABR wave V latency, particularly for listeners with sloping configurations of cochlear hearing loss.

Risk factors for stroke due to cerebral infarction in young adults.

BACKGROUND AND PURPOSE: Stroke in the young is particularly tragic because of the potential for a lifetime of disablement. More than 10% of patients with stroke due to cerebral infarction are aged 55 years or younger. While a number of studies have addressed the issue of stroke mechanism in the young, quantitation of risk factors has rarely been undertaken. Given the importance of risk factor assessment in primary prevention, we aimed to assess this using case-control methodology in a hospital-based series and community-based control subjects. METHODS: A total of 201 consecutive patients with first-onset stroke due to cerebral infarction aged 15 to 55 years (mean, 45.5 years) were accrued from four teaching hospitals during 1985 to 1992 and compared with their age- and sex-matched neighborhood controls. Information concerning potential risk factor exposure status was collected by structured questionnaire at interview. Stroke risks were estimated by calculating the odds ratios with multivariate logistic regression. RESULTS: Significantly increased risk of stroke was found among those with diabetes (odds ratio, 11.6 [95% confidence intervals, 1.2 to 115.2]), hypertension (6.8 [3.3 to 13.9]), heart disease (2.7 [1.1 to 6.4]), current cigarette smoking (2.5 [1.3, 5.0]), and long-term heavy alcohol consumption (> or = 60 g/d) (15.3 [1.0 to 232.0]). However, heavy alcohol ingestion (> or = 60 g) within 24 hours preceding stroke onset was not a risk factor (0.9 [0.3 to 3.4]). CONCLUSIONS: Diabetes, hypertension, heart disease, current smoking, and long-term heavy alcohol consumption are major risk factors for stroke in young adults. Given that the majority of these factors are either correctable or modifiable, prevention strategies may have the potential to reduce the impact of stroke in this age group.

Transcranial Doppler detected cerebral microembolism following carotid endarterectomy. High microembolic signal loads predict postoperative cerebral ischaemia.

Cerebral ischaemia, the most frequent serious complication of carotid endarterectomy (CEA), usually occurs in the early postoperative period and is often the result of thromboembolism. We hypothesized that the early postoperative detection of microembolic ultrasonic signals (MES) with transcranial Doppler ultrasound (TCD) may be of value in identifying patients at risk of postoperative cerebral ischaemia and that the MES rate may be an important determinant in risk prediction. Sixty-five patients undergoing CEA were studied at intervals up to 24 h postoperatively with TCD insonation of the middle cerebral artery ipsilateral to the operation side. Study design was open and prospective with blinded off-line analysis of MES counts. End-points were any focal ischaemic neurological deficit and/or death up to 30 days postoperatively. MES were detected in 69% of cases during the first hour postoperatively with counts ranging from 0 to 212 MES/h (means 19 MES/h; SEM +2- 4.5; median 4 MES/h). In seven cases (10.8%) counts were > 50 MES/h. Five of these seven cases developed ischaemic neurological deficits in the territory of the insonated middle cerebral artery during the monitoring period. The positive predictive value of counts > 50 MES/h for cerebral ischaemia was 0.71. Frequent signals (> 50 MES/h) occur in approximately 10% of cases in the early postoperative phase of CEA and are predictive for the development of ipsilateral focal cerebral ischaemia.

Risk factors for lacunar infarction syndromes.

BACKGROUND AND PURPOSE: Lacunar infarction is an important stroke subgroup with unique clinical and pathologic features, but its relative risks for associated risk factors have been rarely documented. To address this matter, we studied 203 consecutive patients with first-ever stroke due to lacunar infarction admitted to four general hospitals during the period 1985 to 1992. METHODS: We obtained information concerning risk factor exposure status among the patients by interview using a structured questionnaire and by comparison with age- and sex-matched neighborhood controls. Odds ratios were estimated with adjustment for confounding variables by using multivariate logistic regression. RESULTS: Significantly increasing the risk of lacunar stroke were hypertension (with an odds ratio of 8.9 [95% confidence intervals 4.2, 18.8]), current smoking (6.6 [2.9, 14.8]), and diabetes (2.3 [1.0, 5.5]), whereas frequent physical exercise was associated with a significantly decreased risk (0.3 [0.1, 0.7]). There was no risk of lacunar stroke associated with heart disease (odds ratio 1.0 [0.5, 1.9]). CONCLUSIONS: Patients with hypertension or diabetes, and those who currently smoke, are at a higher risk of lacunar stroke, whereas those who undertake regular physical exercise may be at lower risk. The high risk associated with hypertension but absent risk with heart disease supports the "lacunar hypothesis" of a unique pathophysiologic mechanism for lacunar stroke.

The capsular warning syndrome: pathogenesis and clinical features.

Transient ischemic attacks (TIAs) are not homogeneous and may consist of subsets with mechanisms as varied as their stroke counterparts. We describe a form of TIA in 50 patients where crescendo episodes of ischemia were restricted to the region of the internal capsule, usually causing symptoms affecting face, arm, and leg. These patients composed 4.5% of a consecutive series of patients admitted with TIAs over a 15-year period and 33% of all TIAs classified as subcortical. We believe that the ischemia was most often due to hemodynamic phenomena in diseases, single, small penetrating vessels. When cerebral infarction developed, it was usually lacunar and involved a single penetrating vessel, although occasionally striatocapsular or anterior choroidal artery territory infarction occurred. There was no evidence of artery-to-artery or heart-to-artery embolism. Resistance to various forms of therapy, including hemodiluting, anticoagulant, and thrombolytic agents, was common. Because of dramatic and easily recognizable clinical presentation, apparent specific pathophysiologic mechanism, and the development of early capsular stroke in a high proportion of cases (42%), we have termed this the "capsular warning syndrome."

Smoking as a risk factor for cortical ischaemia presumably due to carotid occlusive disease.

Smoking is now a well established risk factor for ischaemic stroke. However, the risk associated with smoking may differ between subgroups of ischaemic stroke. To test the hypothesis that cortical ischaemia due to carotid artery occlusive disease, the latter of which has previously been linked to smoking, may have a higher smoking risk compared to other forms of cerebral ischaemia, we identified 178 cases of cortical ischaemia presumably due to carotid occlusive disease in our previous case-control population and compared the odds ratios (OR) for smoking risk in this group with that in group of 244 cases of other forms of cerebral ischaemia combined. All cases were individually matched for age (+/- 5 years) and sex with neighbourhood controls. Multiple conditional logistic regression was used to adjust for potentially confounding factors. The OR for current smokers in the cortical group was higher than that in the non-cortical group [OR 4.4, 95% confidence interval 2.2, 8.9 vs. 2.1 (1.1, 4.1)], particularly for those who smoked more than 60 pack-years [5.5 (2.2, 14.0) vs. 1.5 (0.6, 3.8)] and those who currently smoked more than one pack per day [20.2 (3.3, 122.3) vs. 2.6 (0.8, 8.2)], but not significantly. Overall, there is some evidence to suggest that smoking may be a more potent risk factor for cortical than for other forms of cerebral ischaemia, particularly at high smoking rates. Further studies are needed to substantiate this finding.

The influence of age on atrial fibrillation as a risk factor for stroke.

To determine the influence of age on atrial fibrillation as a risk factor for cerebral infarction, the Austin Hospital Stroke Unit Register from 1977 to 1990 was reviewed. There were 2279 patients with cerebral infarction (excluding lacunar infarction syndromes) with a mean age of 68.3 years who were identified as subjects, and 800 patients with pseudostroke and lacunar infarction syndromes with a mean age of 64.7 years who were identified as controls. Data concerning potential risk factors for stroke (including sex, age, atrial fibrillation, cardiac disease, hypertension, diabetes, peripheral vascular disease and smoking) were analyzed using multivariate regression techniques. It was found that atrial fibrillation was a significant risk factor for cerebral infarction (excluding lacunar infarction) for all age groups, after adjusting for the effects of other risk factors (P less than .001). However, when age was stratified into four groups, the age-specific odds ratios for atrial fibrillation were not significantly different and no significant interactions between atrial fibrillation and age or other risk factors were found (P greater than 0.1). It was concluded that, although with increasing age atrial fibrillation becomes a more frequent cause of stroke, its potency as a risk factor does not increase correspondingly. There was no significant influence of age on the relationship between atrial fibrillation and cerebral infarction.

Smoking as a risk factor for cerebral ischaemia.

To assess whether a rigorous clinical classification, based on computerised tomography, of patients with cerebral ischaemia would identify subgroups at higher or lower risk with respect to cigarette smoking habits, a case-control study was carried out on 422 cases of first-episode cerebral ischaemia matched for age and sex with 422 community-based neighbourhood controls. Patients with ischaemic stroke due to extracranial or intracranial vascular disease were at higher risk from smoking than has previously been reported for stroke (relative risk 5.7, 95% confidence interval 2.8, 12.0) whereas those with stroke due to cardiac emboli had no excess risk associated with smoking (relative risk 0.4 [0.1, 1.8]). After cessation of smoking, the relative risk declined gradually over 10 years, at the end of which time a significant risk was still evident. This finding may imply that the risk incurred by smoking is due mainly to atheroma formation, rather than transient haematological effects. Exposure to smoking by a spouse was an independent risk factor for the whole group of cerebral ischaemia patients (relative risk 1.7 [1.1, 2.6]), but this was not so for smoking by either parent (relative risk 1.2 [0.8, 1.8]). These findings suggest that smoking is a more potent risk factor for the most common form of ischaemic stroke than has previously been appreciated. The persistent nature of the risk even after cessation of smoking and the possible risk associated with passive exposure strengthens public health arguments against smoking.

Categories of family-mediated abuse and neglect of elderly persons.

The records of 22 cases of family-mediated abuse and neglect of elderly persons were retrospectively reviewed by the physician and nurse responsible for their care using a modification of the OARS Multidimensional Functional Assessment form. Cases were divided into three categories: Category I cases (n = 4) involved extremely impaired elders who received extensive care from the individuals responsible for the abuse or neglect. Category II cases (n = 9) involved impaired elders who received inadequate or intermittent care. Category III cases (n = 9) involved independent elders whose only care needs resulted from threats or violence from relatives. Among the statistically significant differences found between these categories were the age of the abuser, the manifestations of abuse or neglect, the interventions offered, the durations of abuse, and the outcomes of the cases. The results suggest that these three categories represent different subgroups of abused and neglected elderly persons, all with different implications for identification, intervention, and outcome.

Identifying and preventing family-mediated abuse and neglect of elderly persons.

Unexplained trauma, neglected medical problems, failure to thrive, malnutrition, and misuse of medications may be manifestations of family-mediated abuse and neglect of the non-institutionalized elderly person. Physicians frequently overlook or misdiagnose this form of family violence. Access to these persons, assessment, and intervention are facilitated by focusing on the unmet care needs of the elderly person and by moving to meet those needs. Issues of intervention can be clarified by categorizing abuse or neglect as occurring in situations in which the dependency and care needs of the elderly person are paramount or in which the pathologic behavior of the abuser is most evident. The provision of specific support services or legally mandated separation of the elderly person and the abuser can be attempted but the elderly person's right to refuse any intervention must be recognized.

Relationship between psychophysical tuning curves and "suppression".

This study examined two-tone unmasking and auditory frequency selectivity about 3 kHz for the purpose of demonstrating a qualitative relationship between the two. An adaptive 2IFC forward-masking procedure was used to collect psychophysical tuning curves (PTC's) and two-tone masking data under a quiet and noise condition for the same normal-hearing listeners. In the noise condition, a narrowband noise masker, centered one decade down from the probe, was gated on with the tonal masker(s). Kiang and Moxon [J. Acoust. Soc. Am. 55, 620-630 (1974)] have found that low-frequency narrowband noise serves to decrease the sharpness of electrophysiological tuning curves by affecting only the tip segments. The data for four highly practiced listeners indicate that the gated-noise masker was effective in broadening the PTC's and in lessening the magnitude of two-tone unmasking. The mutually reflected changes in tuning curves and in two-tone unmasking indicate a close relationship between frequency selectivity and unmasking: the greater the magnitude of unmasking above the center frequency of the PTC, the sharper the tuning of the PTC.

Two-tone auditory spectral resolution.

Two component complex tones were synthesized so that each member of a complementary pair exhibited identical amplitude modulations; frequency modulations, however, were in opposite directions. Previous work has shown that the discriminability of the members of a complementary pair is related to the envelope-weighted differences in their instantaneous frequency functions. Listeners report that they base their discriminations upon differences in pitch between complementary two component signals. We assumed that the high discriminability found for moderate separations between the two component frequencies would not obtain if the components were resolved into separate critical bands. Thus we could define the just discriminable (75%) frequency separation as a direct estimate of spectral resolving power without recourse to assumptions about masking effectiveness, loudness summation, or other subjective changes thought to depend upon auditory spectral resolving power. Our findings indicate that resolution bandwidths resulting from the discriminability of complex tone pairs approximate the width of the traveling-wave envelope observed by von Békèsy. In light of our results, the implications for other critical bandwidth estimates are discussed.

Effects of dichotically presented simulatneous synchronous and delayed auditory feedback on key tapping performance.

A selective replication of Tsunoda's (1966) application of the DAF key tapping paradigm to the study of functional auditory asymmetry was conducted. Present findings do not offer confirmation of Tsunoda's assertion that most subjects will exhibit performance disruption at a lower intensity level when a vowel is delayed at the right ear and when a pure tone is delayed at the left ear. In the present study, it was found that no difference existed between the pure tone and the vowel delayed to the left ear conditions in terms of performance deterioration. The significant difference in performance disruption between the vowel delayed to the right ear condition and the pure tone delayed to the right ear condition was interpreted to be suggestive of functional auditory asymmetry.