Visuospatial and other "right-hemispheric" functions after long recovery periods in left-hemispherectomized subjects.

Two subjects who had infantile brain damage and left hemispherectomies at the ages of 17 and 18 yr are assessed after 28 and 16 yr recovery periods. Both have intact language and verbal memory abilities. However, on functions normally mediated predominantly by the right hemisphere, including nonverbal memory, higher cognitive visuospatial skills, and complex extrapersonal orientation ability, they are severely impaired. Simple visuospatial perceptual and orientation abilities, emotional expression, and face recognition, also "right-hemispheric" functions, are normal. It is postulated that the right hemisphere, if isolated in infancy, has the potential to take over most cognitive functions. The pattern of intact and impaired abilities shown by these subjects allows a hierarchy of functionally important abilities to be constructed. The functions mediated by the solitary right hemisphere are those most essential for independent survival, and functions that are not represented are those least required.

Visual object agnosia, prosopagnosia, achromatopsia, loss of visual imagery, and autobiographical amnesia following recovery from cortical blindness: case M.H.

A number of higher visual deficits accompanied by severe retrograde autobiographical memory loss following bilateral medial occipital infarctions are described in case M.H. Assessment of M.H.'s visual object agnosia and prospagnosia suggested that he was unable to integrate the elements of a percept to form a meaningful whole. This deficit may occur at the level the percept is encoded into the visual buffer and inspected. M.H. also describes a loss of visual memories, and it is hypothesized that this may similarly be a result of an inability to integrate the elements of the visual representation (e.g. of an object or face) following its generation from long-term visual memory store into the visual buffer. M.H.'s retrograde autobiographical memory loss is postulated to be a consequence of the severe impoverishment of episodic memories that must occur when events originally stored multimodally, must be recalled without any visual component.

Language and memory functions after long recovery periods in left-hemispherectomized subjects.

Two subjects who had infantile brain damage and left hemispherectomies at the ages of 17 and 18 yr are assessed after 28 and 16 yr recovery periods. Deficits on the comprehension of passive-negative sentences disappeared when the subjects read rather than heard the sentences, and performances were normal on the Token and Reporter's Tests, and tests of verbal memory. These results suggest that if damage to the left hemisphere occurs early in life and there is a long recovery period, the right hemisphere can mediate verbal memory and the more subtle aspects of language. This provides support for the hypothesis that the two hemispheres are equipotential for language and verbal memory.

Phonological dyslexia and phonological dysgraphia following left and right hemispherectomy.

Four adults who had hemispherectomies because of severe epilepsy following infantile of childhood damage to one hemisphere of the brain, are assessed on their reading and spelling abilities in an attempt to see if the two hemispheres are equipotential for these abilities in infancy. The psycholinguistic assessments of language processing in aphasia (PALPA) are used, and the results are interpreted from the viewpoint of hypotheses of "normal" right and left hemisphere reading abilities. Overall, the results suggest that the two hemispheres are equipotential at infancy for developing the skills underlying reading, but the left hemisphere is more specialized for the skills underlying spelling. All participants could read learnt regular and irregular words, and abstract and concrete words, suggesting that the reading lexicon develops in line with a normal left hemisphere lexicon, whichever hemisphere remains intact following hemispherectomy. However, poor reading of non-words suggests that the phonological reading route is severely impaired following left hemispherectomy (phonological dyslexia), and somewhat impaired following right hemispherectomy. The right-hemispherectomized participant is only mildly impaired on spelling real words, in contrast to the left-hemispherectomized participants who are markedly impaired. None of the participants could spell non-words, suggesting that the phonological spelling route is impaired following removal of either hemisphere (phonological dysgraphia).

Dyslexia in a right-handed patient with a posterior lesion of the right cerebral hemisphere.

A 44-yr-old man was tested 17 months after he had a benign tumour in the lateral ventricle removed via a transverse surgical incision through the posterior temporal-parietal region of his right hemisphere. As a result of the surgical incision he suffered a number of visuo-spatial deficits, and test results strongly suggested he had speech lateralized in the left hemisphere. His speech and writing were normal but he suffered from a form of dyslexia. Most of the components of his disorder have previously been documented only in patients with left-hemispheric lesions.

Ipsilateral auditory extinction following frontal and basal ganglia lesions of the left hemisphere.

When tested on a dichotic digits listening task, patients with unilateral lesions of the left frontal lobe and left anterior basal ganglia exhibited ipsilateral auditory extinction. This phenomenon has been documented before, but only in patients with lesions involving the region posterior and lateral to the posterior aspect of the left lateral ventricle. As patients with lesions in the equivalent region of the right hemisphere also exhibit extinction of verbal material arriving in their left ears it has been hypothesized that these posterior lesions disrupt an interhemispheric pathway connecting the two temporal lobes. As it appears that the ipsilateral auditory pathways are suppressed under conditions of dichotic stimulation, such an interhemispheric pathway would be the means whereby left-ear verbal stimuli reached the left (speech) hemisphere. Therefore a disruption of this pathway could result in left-ear extinction for verbal material. The finding that left anterior lesions also result in left-ear extinction poses problems for this hypothesis and in particular for the suggested posterior route of the interhemispheric pathway.

Contralesional neglect of constructed visual images in right and left brain-damaged patients.

Patients with left- and right-hemispheric cortical lesions and right-handed control subjects were compared on a task requiring them to judge pairs of shapes as same or different. When the shapes were moved behind a narrow viewing slit, requiring the subjects to mentally construct their horizontal dimensions, patients with right-sided lesions showed relative neglect of the left sides of the shapes, while patients with left-sided lesions showed relative neglect of the right sides. Control patients showed no overall unilateral neglect. All patients exhibited contralesional neglect on this task even if they did not show visual hemineglect on more routine measures.

Dichotic listening in commissurotomized and hemispherectomized subjects.

Three commissurotomized and two left-hemispherectomized subjects were tested on spoken report of sequences of three dichotic pairs of digits. With instruction to report only one digit from each pair, there was an overall advantage to the ear contralateral to the hemisphere mediating speech, but report of ipsilateral-ear digits ranged from 40 to 100%. In commissurotomized subjects, the more extreme ipsilateral suppression under instructions to report all digits may be due to failure to gain access to unattended information stored in the right hemisphere, rather than to suppression of the ipsilateral pathway. However one commissurotmized patient did appear to have access to right-hemisphere items, the result either of subcortical transfer or of external cross-cueing. The hemispherectomized subjects seemed able to store both attended and unattended information in the same hemisphere.

The pathology of neonatal osteomyelitis.

The examination of multiple bones from a child who died of complications of septicemia and osteomyelitis elucidated the pathologic processes of infantile osteomyelitis. From a metaphyseal focus, there is spread in several directions. Most important, the infection can spread across the growth plate, along transphyseal vessels, to penetrate the epiphysis. Areas of direct destruction of growth plate were frequent findings, and allowed another route into the epiphysis.

A case of short rib polydactyly.

A patient with neonatal dwarfism had many characteristics of the Majewski syndrome, except for a cleft lip and abnormalities of internal organs. Absence of these anomalies and presence of more severe pathological changes in bone suggest either a wider spectrum for this disorder or a separate entity.

Missed opportunities? Coercion or commitment: policies of prevention.

The DOTS strategy (directly observed therapy, short course) has been the cornerstone of international TB control policy since the early 1990s. This strategy has provided the international community with an advocacy tool to harness funds for TB as well as a method for helping country programs to achieve high cure rates for TB. But as much as the strategy is seen as successful by some, it is perceived as unsuccessful by others. This paper looks at the results of the introduction of DOTS into control programs and discusses research relating to direct observation of treatment. It asks how policies like DOTS are created, and how they are administered and transferred from the international to the national and finally to the local level. The discipline of public health policy is used to interrogate the creation and history of the DOTS strategy in order to find ways of aiding the transfer of the policy to national and local levels. Finally, the paper asks whether the concepts of "control" and "elimination" continue to be useful in the management of infectious diseases. We ask whether it is time to change the perspective to policies that focus more on the context of implementation and the importance of the development of care, integration, and flexibility rather than cure, targets, and short-term solutions.

Anomalous origin of the right coronary artery from the pulmonary artery.

Three patients with anomalous origin of the right coronary artery from the pulmonary artery are presented together with a review of the 14 patients with this anomaly previously reported. One of the current patients is the youngest to be diagnosed before operation and the youngest to undergo corrective operation. Although the lesion is usually asymptomatic, it may contribute to sudden death. The only suggestive physical finding is a continuous murmur with diastolic accentuation, which is present only in some patients. There are no diagnostic electrocardiographic or chest roentgenographic changes. Diagnosis is made best by selective left coronary arteriography showing retrograde filling of the right coronary artery from collateral vessels. Operative repair should consist either of direct reimplantation of the proximal right coronary artery into the aortic root or of saphenous vein bypass graft to the coronary artery with ligation of its origin. Operation is recommended when the lesion is recognized.

Tuberculosis control and directly observed therapy from the public health/human rights perspective.

Directly observed therapy, short course (DOTS) is the current international strategy for controlling tuberculosis. Decisions have been taken internationally about the increasing tuberculosis epidemic-what to do and why to do it. But do we know bow the DOTS strategy can be implemented most appropriately and what changes need to be made to ensure that it is effective? This paper uses the Public Health/Human Rights framework to discuss TB control from a human rights rather than the biomedical perspective. The aim is to introduce different approaches to the current DOTS strategy in order to find more effective and appropriate ways to treat and care for people with tuberculosis. The paper argues that key dimensions of social, economic and physical access to TB services need to be assessed and accounted for in programme design. This will require that TB control adopt a wider interdisciplinary and multisectoral perspective to complement the current biomedical orientation.

Development of vascularization in the chondroepiphysis of the rabbit.

Although numerous studies have addressed the presence of cartilage canals within developing epiphyses, the chronology of their appearance and their vascular contribution to the developing chondroepiphysis remain to be studied. We have selected a model, similar to the developing human skeletal system, in which extensive cartilage canal development precedes the subsequent secondary ossification process. In the rabbit proximal tibia, both chondroepiphyseal and vascular (cartilage canals) development were quantified from the first evidence of vessels until the formation of the secondary center of ossification. The volume of hyaline cartilage increased 25 times after intraepiphyseal vessels were initially observed. The blood supply, measured in cartilage canal volume, increased 400-fold over the same period. Three distinct cartilage canal morphologies were identifiable before the formation of the secondary center of ossification: (a) an early phase, in which the canals appeared as infoldings derived from the perichondrium; (b) a reactive phase, occurring simultaneously with chondrocyte hypertrophy and characterized by a very large increase in mesenchymal cells within the cartilage canal; and (c) a vascular phase, coincident with mineralization of the matrix, in which the familiar, unitary canal morphology was replaced by that of a vascular plexus. While matrix mineralization and the formation of bone seem dependent on critical cellular events, notably chondrocyte hypertrophy, the role that the vascular supply plays in developing sufficient biological inertia for the ossifying transition must not be underestimated.

Identifying the determinants of tuberculosis control in resource-poor countries: insights from a qualitative study in The Gambia.

Despite the availability of effective treatment, tuberculosis (TB) remains a major cause of death from an infectious disease in the world, particularly in resource-poor countries. Among the chief reasons for this are deficiencies in case tracing and in adherence to treatment. In order to investigate the contribution of non-biological factors to these deficiencies, we carried out a qualitative study in The Gambia, West Africa, from October 2000 to March 2001. The methods used were focus group discussions, interviews, participant and non-participant observation, and case histories. Four domains were distinctively investigated: the TB patients, the community, the health care providers (including programme staff), and the donors and policy makers. Analysis of the data from all these sources indicated the contribution of a wide range of socio-anthropological factors which influence the success or otherwise of the TB control programme in The Gambia, i.e. gender, urban/rural residence, recourse to traditional healers, adherence to national health policies, knowledge about TB, migration, and socio-economic factors. It is concluded that all these factors must be taken into account in formulating interventions to improve detection of TB cases and patient adherence to treatment within the framework of the national TB control programmes, and proposals have been made for targeted interventions.

A prospective study of impairment of cognition and memory and recovery after subarachnoid hemorrhage.

In this prospective study, a series of 89 patients with subarachnoid hemorrhage (SAH), most of whom had a "good" neurological outcome, were assessed with a range of tests of memory and cognition as inpatients and at 10 weeks and 12 months after SAH. On tests of verbal cognition and memory, most patients had scores in the normal range 12 months after SAH. However, a significant number of patients still showed impairment on tests of visuospatial construction and memory, mental flexibility, and psychomotor speed at the 12-month assessment. Statistical analyses were carried out for each test score to see whether aneurysm site, location of blood on the admission computed tomographic scan, vasospasm, ischemia, hydrocephalus, grades at admission to and at discharge from hospital, and Glasgow Outcome Scale score at follow-up were associated with test scores. Aneurysm site was not shown to be associated with performance on any test at any time, and the other complications of SAH had only minimal predictive value. The grade at discharge proved to be the best predictor of impairment of cognition and memory at both follow-up assessments. Older subjects did not recover to the same extent as younger subjects by the 12-month assessment. The authors conclude that the diffuse effects of SAH are more important than focal neuropathology in relation to cognitive impairment in this group of patients.

Neurological and psychosocial outcome 4 to 7 years after subarachnoid hemorrhage.

OBJECTIVE: Previous studies have demonstrated that many patients with good neurological outcomes still experience excessive fatigue, cognitive impairments, and lowered work status 1 year after subarachnoid hemorrhage (SAH). Does recovery continue for many years or are survivors of SAH left with permanent disabilities? We describe the long-term outcome. METHODS: Approximately 50% (n = 123) of the patients who survived SAH for more than 3 years from a population of 1.5 million and who had participated in research studies at the time of their SAH were interviewed 4 to 7 years later by telephone or questionnaire. Participants did not differ from the 126 unsurveyed survivors in age, gender, SAH grades, aneurysm sites, or complications. RESULTS: Most patients thought their recovery to be satisfactory to good, although some reported memory problems (41%), headaches (16.5%), daytime sleepiness (35%), problems sleeping at night (26%), a reduced ability to work (20%), and a changed personality (48.3%). Many had reduced their smoking and drinking. Each of 24 of the 121 participants for whom seizure data were available (all with clipped aneurysms) had suffered at least one seizure, but only each of 10 had suffered two or more seizures since hospital discharge. Relative youth was the only significant predictor of seizures, with strong trends observed between seizures and a poor Glasgow Outcome Scale score at 10 weeks or between seizures and an ischemic neurological deficit. No evidence for the effectiveness of prophylactic anticonvulsants was demonstrated. CONCLUSION: Survivors of SAH continue to recover for years and develop good coping skills and a positive attitude toward their recovery, even when they experience ongoing problems. Few are left with disabling headaches or epilepsy.

Too little, too late: does tirilazad mesylate reduce fatigue after subarachnoid hemorrhage?

OBJECTIVE: Trials assessing drug effectiveness for treatment of subarachnoid hemorrhage (SAH) often use mortality rates and Glasgow Outcome Scale scores as outcome measures. Neuropsychological and psychosocial measures might be more sensitive to outcomes, especially for patients of better-grade status. METHODS: Eighteen of a total of 31 patients enrolled in the New Zealand arm of the Upjohn international, double-blind, therapeutic trial of tirilazad mesylate for women with SAH were assessed neuropsychologically and psychosocially 3 months after SAH. The 13 not assessed either had died or remained vegetative (9 patients), did not speak English (1 patient), or did not consent (3 patients). The drug code was broken after all assessments had been scored. RESULTS: Sixteen of the 31 patients had received the drug and 15 the vehicle. There were no differences between the two groups with respect to age, grades assessed at admission and 14 weeks after SAH, Glasgow Outcome Scale scores assessed at 3 months, or mortality rates. In the subgroup assessed neuropsychologically, nine patients were in each of the drug- and vehicle-treated groups. No differences were found with respect to grades, Glasgow Outcome Scale scores, or values for an index that measured cognitive impairment in all tests, but vehicle-treated patients were more impaired with respect to measures of concentration, sustained attention, and psychomotor speed (P < 0.02), as well as debilitating fatigue (P < 0.01). CONCLUSION: The finding that the patients in the drug-treated group exhibited fewer impairments typical of diffuse cortical damage could be viewed as being consistent with the hypothesis that tirilazad mesylate protects neurons. Given the small size of this study, these results require confirmation with larger patient groups. Future drug trials should consider including neuropsychological tests in assessments of outcomes after SAH. If this is too costly, questions regarding fatigue levels might prove worthwhile.

Organic solvent induced chronic toxic encephalopathy: extent of recovery, and associated factors, following cessation of exposure.

AIMS: to determine extent and nature of recovery of solvent induced chronic toxic encephalopathy (CTE). METHOD: 21 confirmed cases had repeat neuropsychological and clinical assessments 6-42 (mean 27) months after ceasing exposure. An exposure score was calculated for each. RESULTS: less than half (42.8%) showed evidence of improvement, which showed no association with time away from solvents or exposure score. The more severely affected at first diagnosis were nearly four times more likely to improve (RR 3.85 (95%CI 1.03, 14.38), p = 0.03). Those with no subjective improvement were five times more likely to have been on antidepressants (RR 5.25 (95%CI 0.83, 33.2), p=0.02). CONCLUSIONS: The largely irreversible nature of Type 2 CTE is confirmed. The study results suggest that severity of effect and partial recovery are not dose related but multifactorial, with individual susceptibility probably important. Concomitant depression may also adversely influence recovery.