Language networks in anophthalmia: maintained hierarchy of processing in 'visual' cortex

Imaging studies in blind subjects have consistently shown that sensory and cognitive tasks evoke activity in the occipital cortex, which is normally visual. The precise areas involved and degree of activation are dependent upon the cause and age of onset of blindness. Here, we investigated the cortical language network at rest and during an auditory covert naming task in five bilaterally anophthalmic subjects, who have never received visual input. When listening to auditory definitions and covertly retrieving words, these subjects activated lateral occipital cortex bilaterally in addition to the language areas activated in sighted controls. This activity was significantly greater than that present in a control condition of listening to reversed speech. The lateral occipital cortex was also recruited into a left-lateralized resting-state network that usually comprises anterior and posterior language areas. Levels of activation to the auditory naming and reversed speech conditions did not differ in the calcarine (striate) cortex. This primary 'visual' cortex was not recruited to the left-lateralized resting-state network and showed high interhemispheric correlation of activity at rest, as is typically seen in unimodal cortical areas. In contrast, the interhemispheric correlation of resting activity in extrastriate areas was reduced in anophthalmia to the level of cortical areas that are heteromodal, such as the inferior frontal gyrus. Previous imaging studies in the congenitally blind show that primary visual cortex is activated in higher-order tasks, such as language and memory to a greater extent than during more basic sensory processing, resulting in a reversal of the normal hierarchy of functional organization across 'visual' areas. Our data do not support such a pattern of organization in anophthalmia. Instead, the patterns of activity during task and the functional connectivity at rest are consistent with the known hierarchy of processing in these areas normally seen for vision. The differences in cortical organization between bilateral anophthalmia and other forms of congenital blindness are considered to be due to the total absence of stimulation in 'visual' cortex by light or retinal activity in the former condition, and suggests development of subcortical auditory input to the geniculo-striate pathway.

Co-localisation of abnormal brain structure and function in specific language impairment

We assessed the relationship between brain structure and function in 10 individuals with specific language impairment (SLI), compared to six unaffected siblings, and 16 unrelated control participants with typical language. Voxel-based morphometry indicated that grey matter in the SLI group, relative to controls, was increased in the left inferior frontal cortex and decreased in the right caudate nucleus and superior temporal cortex bilaterally. The unaffected siblings also showed reduced grey matter in the caudate nucleus relative to controls. In an auditory covert naming task, the SLI group showed reduced activation in the left inferior frontal cortex, right putamen, and in the superior temporal cortex bilaterally. Despite spatially coincident structural and functional abnormalities in frontal and temporal areas, the relationships between structure and function in these regions were different. These findings suggest multiple structural and functional abnormalities in SLI that are differently associated with receptive and expressive language processing.

Changes in neural activity associated with learning to articulate novel auditory pseudowords by covert repetition

Learning to articulate novel combinations of phonemes that form new words through a small number of auditory exposures is crucial for development of language and our capacity for fluent speech, yet the underlying neural mechanisms are largely unknown. We used functional magnetic resonance imaging to reveal repetition-suppression effects accompanying such learning and reflecting discrete changes in brain activity due to stimulus-specific fine-tuning of neural representations. In an event-related design, subjects were repeatedly exposed to auditory pseudowords, which they covertly repeated. Covert responses during scanning and postscanning overt responses showed evidence of learning. An extensive set of regions activated bilaterally when listening to and covertly repeating novel pseudoword stimuli. Activity decreased, with repeated exposures, in a subset of these areas mostly in the left hemisphere, including premotor cortex, supplementary motor area, inferior frontal gyrus, superior temporal cortex, and cerebellum. The changes most likely reflect more efficient representation of the articulation patterns of these novel words in two connected systems, one involved in the perception of pseudoword stimuli (in the left superior temporal cortex) and one for processing the output of speech (in the left frontal cortex). Both of these systems contribute to vocal learning.

Neural activity of the anterior insula in emotional processing depends on the individuals' emotional susceptibility

Differences in personality factors between individuals may manifest themselves with different patterns of neural activity while individuals process stimuli with emotional content. We attempted to verify this hypothesis by investigating emotional susceptibility (ES), a specific emotional trait of the human personality defined as the tendency to "experience feelings of discomfort, helplessness, inadequacy and vulnerability" after exposure to stimuli with emotional valence. By administering a questionnaire evaluating the individuals' ES, we selected two groups of participants with high and low ES respectively. Then, we used functional magnetic resonance imaging to investigate differences between the groups in the neural activity involved while they were processing emotional stimuli in an explicit (focusing on the content of the stimuli) or an incidental (focusing on spatial features of the stimuli, irrespectively of their content) way. The results showed a selective difference in brain activity between groups only in the explicit processing of the emotional stimuli: bilateral activity of the anterior insula was present in subjects with high ES but not in subjects with low ES. This difference in neural activity within the anterior insula proved to be purely functional since no brain morphological differences were found between groups, as assessed by a voxel-based morphometry analysis. Although the role of the anterior insula in the processing of contexts perceived as emotionally salient is well established, the present study provides the first evidence of a modulation of the insular activity depending on the individuals' ES trait of personality.

Structural and functional abnormalities of the motor system in developmental stuttering

Though stuttering is manifest in its motor characteristics, the cause of stuttering may not relate purely to impairments in the motor system as stuttering frequency is increased by linguistic factors, such as syntactic complexity and length of utterance, and decreased by changes in perception, such as masking or altering auditory feedback. Using functional and diffusion imaging, we examined brain structure and function in the motor and language areas in a group of young people who stutter. During speech production, irrespective of fluency or auditory feedback, the people who stuttered showed overactivity relative to controls in the anterior insula, cerebellum and midbrain bilaterally and underactivity in the ventral premotor, Rolandic opercular and sensorimotor cortex bilaterally and Heschl's gyrus on the left. These results are consistent with a recent meta-analysis of functional imaging studies in developmental stuttering. Two additional findings emerged from our study. First, we found overactivity in the midbrain, which was at the level of the substantia nigra and extended to the pedunculopontine nucleus, red nucleus and subthalamic nucleus. This overactivity is consistent with suggestions in previous studies of abnormal function of the basal ganglia or excessive dopamine in people who stutter. Second, we found underactivity of the cortical motor and premotor areas associated with articulation and speech production. Analysis of the diffusion data revealed that the integrity of the white matter underlying the underactive areas in ventral premotor cortex was reduced in people who stutter. The white matter tracts in this area via connections with posterior superior temporal and inferior parietal cortex provide a substrate for the integration of articulatory planning and sensory feedback, and via connections with primary motor cortex, a substrate for execution of articulatory movements. Our data support the conclusion that stuttering is a disorder related primarily to disruption in the cortical and subcortical neural systems supporting the selection, initiation and execution of motor sequences necessary for fluent speech production.

Changes in white matter microstructure during adolescence

Postmortem histological studies have demonstrated that myelination in human brain white matter (WM) continues throughout adolescence and well into adulthood. We used in vivo diffusion-weighted magnetic resonance imaging to test for age-related WM changes in 42 adolescents and 20 young adults. Tract-Based Spatial Statistics (TBSS) analysis of the adolescent data identified widespread age-related increases in fractional anisotropy (FA) that were most significant in clusters including the body of the corpus callosum and right superior corona radiata. These changes were driven by changes in perpendicular, rather than parallel, diffusivity. These WM clusters were used as seeds for probabilistic tractography, allowing us to identify the regions as belonging to callosal, corticospinal, and prefrontal tracts. We also performed voxel-based morphometry-style analysis of conventional T1-weighted images to test for age-related changes in grey matter (GM). We identified a cluster including right middle frontal and precentral gyri that showed an age-related decrease in GM density through adolescence and connected with the tracts showing age-related WM FA increases. The GM density decrease was highly significantly correlated with the WM FA increase in the connected cluster. Age-related changes in FA were much less prominent in the young adult group, but we did find a significant age-related increase in FA in the right superior longitudinal fascicle, suggesting that structural development of this pathway continues into adulthood. Our results suggest that significant microstructural changes in WM continue throughout adolescence and are associated with corresponding age-related changes in cortical GM regions.

Stimulating language: insights from TMS

Fifteen years ago, Pascual-Leone and colleagues used transcranial magnetic stimulation (TMS) to investigate speech production in pre-surgical epilepsy patients and in doing so, introduced a novel tool into language research. TMS can be used to non-invasively stimulate a specific cortical region and transiently disrupt information processing. These 'virtual lesion' studies offer not only the ability to explore causal relations between brain regions and language functions absent in functional neuroimaging, but also spatial and temporal precision not typically available in patient studies. For instance, TMS has been used to demonstrate functionally distinct sub-regions of the left inferior frontal gyrus; to clarify the relationship between pre-morbid language organization and susceptibility to unilateral lesions and to investigate the contribution of both left and right hemisphere language areas in recovery from aphasia. When TMS is used as a measure of functional connectivity, it demonstrates a close link between action words and motor programmes; it suggests a potential evolutionary link between hand gestures and language and it suggests a role in speech perception for the motor system underlying speech production. In combination with functional neuroimaging, it can elucidate the circuits responsible for this involvement. Finally, TMS may even be useful for enhancing recovery in aphasic patients. In other words, TMS has already become an important tool for studying language at both the cognitive and neural levels, and it is clear that further developments in TMS methodology are likely to result in even greater opportunities for language research.

Tract-based spatial statistics: voxelwise analysis of multi-subject diffusion data

There has been much recent interest in using magnetic resonance diffusion imaging to provide information about anatomical connectivity in the brain, by measuring the anisotropic diffusion of water in white matter tracts. One of the measures most commonly derived from diffusion data is fractional anisotropy (FA), which quantifies how strongly directional the local tract structure is. Many imaging studies are starting to use FA images in voxelwise statistical analyses, in order to localise brain changes related to development, degeneration and disease. However, optimal analysis is compromised by the use of standard registration algorithms; there has not to date been a satisfactory solution to the question of how to align FA images from multiple subjects in a way that allows for valid conclusions to be drawn from the subsequent voxelwise analysis. Furthermore, the arbitrariness of the choice of spatial smoothing extent has not yet been resolved. In this paper, we present a new method that aims to solve these issues via (a) carefully tuned non-linear registration, followed by (b) projection onto an alignment-invariant tract representation (the "mean FA skeleton"). We refer to this new approach as Tract-Based Spatial Statistics (TBSS). TBSS aims to improve the sensitivity, objectivity and interpretability of analysis of multi-subject diffusion imaging studies. We describe TBSS in detail and present example TBSS results from several diffusion imaging studies.

Word and nonword repetition in bilingual subjects: a PET study

Learning a specific skill during childhood may partly determine the functional organization of the adult brain. This hypothesis led us to study brain activation patterns using positron emission tomography (PET), in which we compared word and nonword repetition in 10 right-handed native English-speakers (L1) who were proficient in their second language, French (L2), which was learned after the age of 5 years. Regional cerebral blood flow (rCBF) was measured by the H2 15O intravenous bolus method with intersubject averaging and coregistration of magnetic resonance and PET images. A comparison of CBF changes when repeating words in L2 with those seen when repeating words in (L1) demonstrated that the pattern of CBF was similar across the two conditions, with several significant CBF differences in the vicinity of the left insular cortex, ventral premotor region, and in the striatum. We hypothesize that these regions are activated when subjects are required to repeat known words, showing increased activity when there are increased articulatory demands imposed by speaking L2. Comparisons of nonword repetition in L1 and L2 revealed increased activity for L2 in the left ventral premotor region and in the cerebellum; rCBF increases were also observed in these regions in both L1 and L2 with increased number of syllables and increased articulatory complexity, suggesting a role for these regions in the complex motor control needed for the production of novel sequences.

Asymmetries of the planum temporale and Heschl's gyrus: relationship to language lateralization

Morphological asymmetries favouring the left hemisphere in the planum temporale (PT) and Heschl's gyrus (HG) have both been presumed to relate to the typical left-hemisphere dominance for language functions. However, a direct link between structure and function has not been clearly established. The present study investigates this issue by measuring the volume of the PT and HG on the MRI scans of epilepsy patients classified into three groups: left speech group (LSG; n = 20), right speech group (RSG; n = 11) and bilateral speech group (BSG; n = 13), as assessed by the intracarotid Sodium Amytal procedure. Additionally, an automatic voxel-based morphometry (VBM) analysis was performed to explore collateral structural asymmetries. Although leftward structural asymmetries were found in the PT, consistent with the literature, they did not relate to language lateralization. For HG we also replicated asymmetries favouring the left side; interestingly, three of the individuals within the RSG showed a strongly reversed asymmetry, but as a whole the structure-function relationship for HG was not obligatory. The VBM analysis revealed a grey-matter concentration difference in the posterior part of the inferior frontal gyrus (pars opercularis, corresponding functionally to Broca's area), which favoured the left hemisphere in the LSG, and the right hemisphere in the RSG. The findings suggest that this frontal cortical region bears a direct relationship to language lateralization, which may be related to use-dependent plasticity in patients with language reorganization.

Hemispheric Specialization for Processing Auditory Nonspeech Stimuli

The left hemisphere specialization for speech perception might arise from asymmetries at more basic levels of auditory processing. In particular, it has been suggested that differences in "temporal" and "spectral" processing exist between the hemispheres. Here we used functional magnetic resonance imaging to test this hypothesis further. Fourteen healthy volunteers listened to sequences of alternating pure tones that varied in the temporal and spectral domains. Increased temporal variation was associated with activation in Heschl's gyrus (HG) bilaterally, whereas increased spectral variation activated the superior temporal gyrus (STG) bilaterally and right posterior superior temporal sulcus (STS). Responses to increased temporal variation were lateralized to the left hemisphere; this left lateralization was greater in posteromedial HG, which is presumed to correspond to the primary auditory cortex. Responses to increased spectral variation were lateralized to the right hemisphere specifically in the anterior STG and posterior STS. These findings are consistent with the notion that the hemispheres are differentially specialized for processing auditory stimuli even in the absence of linguistic information.

Deterministic photon transport calculations in general geometry for external beam radiation therapy

A deterministic method is described for performing three-dimensional (3D) photon transport calculations of a LINAC head and phantom/patient geometry to obtain dose distributions for therapy planning. The space, energy, and directional-dependent photon flux density is obtained by numerically solving the Boltzmann equation in general 3D geometry using the method of characteristics. The deterministic transport calculations use similar ray tracing routines as found in Monte Carlo (MC) codes. A special treatment is developed to better represent the impact of scattering from accelerator head components. Equations are presented for computing the water kerma distribution due to the uncollided and collided photon flux density field in the patient region. Kerma results obtained from the deterministic computation are compared to Monte Carlo values for a variety of source spectra and field sizes. The agreement for kerma values in the beam is usually within the MC uncertainties. It is concluded that the deterministic method is a rigorous, first-principles approach that could provide a superior alternative to Monte Carlo calculations for some types of problems. However additional development is needed to provide capability for 3D electron transport calculations.

Developmental amnesia: effect of age at injury

Hypoxic-ischemic events sustained within the first year of life can result in developmental amnesia, a disorder characterized by markedly impaired episodic memory and relatively preserved semantic memory, in association with medial temporal pathology that appears to be restricted to the hippocampus. Here we compared children who had hypoxic-ischemic events before 1 year of age (early group, n = 6) with others who showed memory problems after suffering hypoxic-ischemic events between the ages of 6 and 14 years (late group, n = 5). Morphometric analyses of the whole brain revealed that, compared with age-matched controls, both groups had bilateral abnormalities in the hippocampus, putamen, and posterior thalamus, as well as in the right retrosplenial cortex. The two groups also showed similar reductions (approximately 40%) in hippocampal volumes. Neuropsychologically, the only significant differences between the two were on a few tests of immediate memory, where the early group surpassed the late group. The latter measures provided the only clear indication that very early injury can lead to greater functional sparing than injury acquired later in childhood, due perhaps to the greater plasticity of the infant brain. On measures of long-term memory, by contrast, the two groups had highly similar profiles, both showing roughly equivalent preservation of semantic memory combined with marked impairment in episodic memory. It thus appears that, if this selective memory disorder is a special syndrome related to the early occurrence of hypoxia-induced damage, then the effective age at injury for this syndrome extends from birth to puberty.

Seeing and hearing speech excites the motor system involved in speech production

The perception of action is associated with increased activity in motor regions, implicating such regions in the recognition, understanding and imitation of actions. We examined the possibility that perception of speech, both auditory and visual, would also result in changes in the excitability of the motor system underlying speech production. Transcranial magnetic stimulation was applied to the face area of primary motor cortex to elicit motor-evoked potentials in the lip muscles. The size of the motor-evoked potentials was compared under the following conditions: listening to speech, listening to non-verbal sounds, viewing speech-related lip movements, and viewing eye and brow movements. Compared to control conditions, listening to and viewing speech enhanced the size of the motor-evoked potential. This effect was only seen in response to stimulation of the left hemisphere; stimulation of the right hemisphere produced no changes in motor-evoked potentials in any of the conditions. In a control experiment, the size of the motor-evoked potentials elicited in the muscles of the right hand did not differ among conditions, suggesting that speech-related changes in excitability are specific to the lip muscles. These results provide evidence that both auditory and visual speech perception facilitate the excitability of the motor system involved in speech production.

Bilateral brain abnormalities associated with dominantly inherited verbal and orofacial dyspraxia

The KE family is a large three-generational pedigree in which half of the members suffer from a verbal and orofacial dyspraxia in association with a point mutation in the FOXP2 gene. This report extends previous voxel-based morphometric analyses of magnetic resonance imaging (MRI) scans (Watkins et al. [2002] Brain 125:465-478) using a bilateral conjunction analysis. This searches specifically for areas of grey matter density that differ bilaterally in the affected members compared with both matched controls and the unaffected family members. 3-D T1-weighted MRI datasets of 17 family members (10 affected, 7 unaffected) and matched controls were compared. The most significant findings were reduced grey matter density bilaterally in the caudate nucleus, the cerebellum, and the left and right inferior frontal gyrus in the affected members. In addition, increased grey matter density was found bilaterally in the planum temporale. These results confirm that a point mutation in FOXP2 is associated with several bilateral grey matter abnormalities in both motor and language related regions. The results also demonstrate the advantages of using a conjunction analysis when bilateral abnormalities are suspected.

MRI analysis of an inherited speech and language disorder: structural brain abnormalities

Analyses of brain structure in genetic speech and language disorders provide an opportunity to identify neurobiological phenotypes and further elucidate the neural bases of language and its development. Here we report such investigations in a large family, known as the KE family, half the members of which are affected by a severe disorder of speech and language, which is transmitted as an autosomal-dominant monogenic trait. The structural brain abnormalities associated with this disorder were investigated using two morphometric methods of MRI analysis. A voxel-based morphometric method was used to compare the amounts of grey matter in the brains of three groups of subjects: the affected members of the KE family, the unaffected members and a group of age-matched controls. This method revealed a number of mainly motor- and speech-related brain regions in which the affected family members had significantly different amounts of grey matter compared with the unaffected and control groups, who did not differ from each other. Several of these regions were abnormal bilaterally, including the caudate nucleus, which was of particular interest because this structure was also found to show functional abnormality in a related PET study. We performed a more detailed volumetric analysis of this structure. The results confirmed that the volume of this nucleus was reduced bilaterally in the affected family members compared with both the unaffected members and the group of age-matched controls. This reduction in volume was most evident in the superior portion of the nucleus. The volume of the caudate nucleus was significantly correlated with the performance of affected family members on a test of oral praxis, a test of non-word repetition and the coding subtest of the Wechsler Intelligence Scale. These results thus provide further evidence of a relationship between the abnormal development of this nucleus and the impairments in oromotor control and articulation reported in the KE family.

Behavioural analysis of an inherited speech and language disorder: comparison with acquired aphasia

Genetic speech and language disorders provide the opportunity to investigate the biological bases of language and its development. Critical to these investigations are the definition of behavioural phenotypes and an understanding of their interaction with epigenetic factors. Here, we report our investigations of the KE family, half the members of which are affected by a severe disorder of speech and language, which is transmitted as an autosomal-dominant monogenic trait. The cognitive manifestations of this disorder were investigated using a number of linguistic and non-linguistic tests. The aims of these investigations were to establish the existence of a 'core' deficit, or behavioural phenotype, and to explain how such a deficit during development might give rise to the range of other impairments demonstrated by affected family members. The affected family members were compared both with the unaffected members and with a group of adult patients with aphasia resulting from a stroke. The score on a test of repetition of non-words with complex articulation patterns successfully discriminated the affected and unaffected family members. The affected family members and the patients with aphasia had remarkably similar profiles of impairment on the tests administered. Pre-morbidly, however, the patients with aphasia had enjoyed a normal course of cognitive development and language experience. This benefit was reflected on a number of tests in which the patients with aphasia performed significantly better than the affected family members and, in the case of some tests, at normal levels. We suggest that, in the affected family members, the verbal and non-verbal deficits arise from a common impairment in the ability to sequence movement or in procedural learning. Alternatively, the articulation deficit, which itself might give rise to a host of other language deficits, is separate from a more general verbal and non-verbal developmental delay.

Structural asymmetries in the human brain: a voxel-based statistical analysis of 142 MRI scans

The use of computational approaches in the analysis of high resolution magnetic resonance images (MRI) of the human brain provides a powerful tool for in vivo studies of brain anatomy. Here, we report results obtained with a voxel-wise statistical analysis of hemispheric asymmetries in regional 'amounts' of gray matter, based on MRI scans obtained in 142 healthy young adults. Firstly, the voxel-wise analysis detected the well-known frontal (right > left) and occipital (left > right) petalias. Secondly, our analysis confirmed the presence of left-greater-than-right asymmetries in several posterior language areas, including the planum temporale and the angular gyrus; no significant asymmetry was detected in the anterior language regions. We also found previously described asymmetries in the cingulate sulcus (right > left) and the caudate nucleus (right > left). Finally, in some brain regions we observed highly significant asymmetries that were not reported before, such as in the anterior insular cortex (right > left). The above asymmetries were observed in men and women. Our results thus provide confirmation of the known structural asymmetries in the human brain as well as new findings that may stimulate further research of hemispheric specialization.

Changes in mental health and service use after termination of SSI benefits

OBJECTIVE

Supplemental Security Income (SSI) benefits for a substance abuse disability were terminated by federal legislation as of January 1, 1997. This study examined the changes in mental health and in the use of mental health services two years after the legislation was implemented among individuals who had been receiving benefits under this classification.

METHODS

From a random sample of 400 SSI beneficiaries in Los Angeles, 253 were interviewed at the time the legislation took effect and again at 12-month, 18-month, and 24-month follow-ups. The study subjects were characterized by income source after the legislation and by probable mental health diagnosis. Their use of mental health services was also measured.

RESULTS

The mental health status of the participants remained unchanged between baseline and 24-month follow-up. The proportion who reported any use of mental health services decreased, primarily among those who continued receiving SSI benefits under a different classification. Among those who lost SSI benefits, emergency department visits and hospitalizations did not increase, and rates of outpatient visits remained the same.

CONCLUSIONS

Contrary to expectations, the mental health status of individuals who had been receiving SSI benefits for a substance abuse disability did not worsen after the benefits were terminated. Local safety nets and reclassification under another disability may have mitigated the effects of the policy change. The results of this study underscore the need for longitudinal data to inform policy decisions.

A national survey of care for persons with co-occurring mental and substance use disorders

OBJECTIVE

The delivery of appropriate treatment to persons who have mental and substance use disorders is of increasing concern to clinicians, administrators, and policy makers. This study sought to describe use of appropriate mental health and comprehensive substance abuse care among adults in the United States with probable co-occurring disorders.

METHODS

Data from the Healthcare for Communities survey, which is based on a national household sample studied in 1997 and 1998, were used to identify individuals who had probable co-occurring mental and substance use disorders. The sociodemographic and clinical characteristics of these individuals and their use of services were recorded. Logistic regression analysis was used to identify variables associated with receipt of mental health and substance abuse treatment and with receipt of appropriate treatment.

RESULTS

Estimates for the U.S. adult population based on the weighted survey data indicated that 3 percent of the population had co-occurring disorders. Seventy-two percent did not receive any specialty mental health or substance abuse treatment in the previous 12 months; only 8 percent received both specialty mental health care and specialty substance abuse treatment. Only 23 percent received appropriate mental health care, and 9 percent received supplemental substance abuse treatment. Perceived need for treatment was strongly associated with receipt of any mental health care and with receipt of appropriate care.

CONCLUSIONS

Despite the availability of effective treatments, most individuals who had co-occurring mental health and substance use problems were not receiving effective treatment. Efforts to improve the care provided to persons who have co-occurring disorders should focus on strategies that increase the delivery of effective treatment.

Health information on the Internet: accessibility, quality, and readability in English and Spanish

CONTEXT

Despite the substantial amount of health-related information available on the Internet, little is known about the accessibility, quality, and reading grade level of that health information.

OBJECTIVE

To evaluate health information on breast cancer, depression, obesity, and childhood asthma available through English- and Spanish-language search engines and Web sites.

DESIGN AND SETTING

Three unique studies were performed from July 2000 through December 2000. Accessibility of 14 search engines was assessed using a structured search experiment. Quality of 25 health Web sites and content provided by 1 search engine was evaluated by 34 physicians using structured implicit review (interrater reliability >0.90). The reading grade level of text selected for structured implicit review was established using the Fry Readability Graph method.

MAIN OUTCOME MEASURES

For the accessibility study, proportion of links leading to relevant content; for quality, coverage and accuracy of key clinical elements; and grade level reading formulas.

RESULTS

Less than one quarter of the search engine's first pages of links led to relevant content (20% of English and 12% of Spanish). On average, 45% of the clinical elements on English- and 22% on Spanish-language Web sites were more than minimally covered and completely accurate and 24% of the clinical elements on English- and 53% on Spanish-language Web sites were not covered at all. All English and 86% of Spanish Web sites required high school level or greater reading ability.

CONCLUSION

Accessing health information using search engines and simple search terms is not efficient. Coverage of key information on English- and Spanish-language Web sites is poor and inconsistent, although the accuracy of the information provided is generally good. High reading levels are required to comprehend Web-based health information.

The health and mental health of disabled substance abusers

In 1996 Congress terminated Supplemental Security Income (SSI) benefits to individuals disabled by substance abuse. Although most were expected to continue benefits under another disability category, 64% were not reclassified. This article examines data from a longitudinal study of individuals in Los Angeles County affected by the legislation. While poor physical health predicted both continued SSI benefits and receipt of public income assistance, many individuals reporting significant mental and physical health problems were not reclassified and did not receive public income assistance, raising concern for their welfare. Local safety nets may become increasingly important for this population.

Oral dyspraxia in inherited speech and language impairment and acquired dysphasia

Half of the members of the KE family suffer from an inherited verbal dyspraxia. The affected members of the family have a lasting impairment in phonology and syntax. They were given various tests of oral praxis to investigate whether their deficit extends to nonverbal movements. Performance was compared to adult patients with acquired nonfluent dysphasia, those with comparable right-hemisphere lesions, and age-matched controls. Affected family members and patients with nonfluent dysphasia were impaired overall at performing oral movements, particularly combinations of movements. It is concluded that affected members of the KE family resemble patients with acquired dysphasia in having difficulties with oral praxis and that speech and language problems of affected family members arise from a lower level disorder.

Developmental amnesia associated with early hypoxic-ischaemic injury

We recently reported on three young patients with severe impairments of episodic memory resulting from brain injury sustained early in life. These findings have led us to hypothesize that such impairments might be a previously unrecognized consequence of perinatal hypoxic-ischaemic injury. Neuropsychological and quantitative magnetic resonance investigations were carried out on five young patients, all of whom had suffered hypoxic-ischaemic episodes at or shortly after birth. All five patients showed severe impairments of episodic memory (memory for events), with relative preservation of semantic memory (memory for facts). However, none had any of the major neurological deficits that are typically associated with hypoxic-ischaemic injury, and all attended mainstream schools. Quantitative magnetic resonance investigations revealed severe bilateral hippocampal atrophy in all cases. As a group, the patients also showed bilateral reductions in grey matter in the regions of the putamen and the ventral part of the thalamus. On the basis of their clinical histories and the pattern of magnetic resonance findings, we attribute the patients' pathology and associated memory impairments primarily to hypoxic-ischaemic episodes sustained very early in life. We suggest that the degree of hypoxia-ischaemia was sufficient to produce selective damage to particularly vulnerable regions of the brain, notably the hippocampi, but was not sufficient to result in the more severe neurological and cognitive deficits that can follow hypoxic-ischaemic injury. The impairments in episodic memory may be difficult to recognize, particularly in early childhood, but this developmental amnesia can have debilitating consequences, both at home and at school, and may preclude independent life in adulthood.

Termination of social security benefits among Los Angeles recipients disabled by substance abuse

OBJECTIVES

Although a 1996 federal law terminated Social Security disability benefits to individuals disabled primarily by drug addiction and alcoholism, many were expected to successfully appeal for recertification based on mental illness. This study examined appeal and recertification in Los Angeles County.

METHODS

Data for 2,001 persons receiving Social Security disability benefits in 1996 because of substance abuse disability were obtained from the referral and monitoring agency, where each person had completed the Addiction Severity Index (ASI) during an initial visit in the past two years. Administrative data were obtained from the Social Security Administration. Severity of psychiatric symptoms--low, medium, or high--was based on the composite score on the ASI psychiatric subscale. Logistic regression analyses examined the relationship between severity and appeal and recertification status.

RESULTS

Fifty-one percent of the subjects scored in the medium- or high-severity range. Appeals were made by 80 percent of the 506 recipients with high scores, 72 percent of the 510 recipients with medium scores, and 74 percent of the 985 recipients with low scores. Recertification rates were 60 percent, 45 percent, and 47 percent, respectively. Compared with recipients who had low scores, those with high scores were more likely to appeal and to be recertified. However, benefits were terminated for 51 percent of recipients with high scores, including all those who did not appeal.

CONCLUSIONS

Many recipients of Social Security disability benefits with comorbid psychiatric problems lost benefits either because they did not appeal or because their appeal was denied.

The role of gender in engaging the dually diagnosed in treatment

Individuals with both a serious mental illness and substance abuse are particularly difficult to engage in treatment. Given known gender differences in both substance abuse and schizophrenia, we examined the impact of gender on treatment engagement. Qualitative interviews with ten males and eleven females focused on how the client perceived the engagement process, and what obstacles they faced. While both males and females are difficult to engage, the interviews suggest that they experience the process differently and that they face different obstacles. We discuss the implication for service providers.

Neural basis of an inherited speech and language disorder

Investigation of the three-generation KE family, half of whose members are affected by a pronounced verbal dyspraxia, has led to identification of their core deficit as one involving sequential articulation and orofacial praxis. A positron emission tomography activation study revealed functional abnormalities in both cortical and subcortical motor-related areas of the frontal lobe, while quantitative analyses of magnetic resonance imaging scans revealed structural abnormalities in several of these same areas, particularly the caudate nucleus, which was found to be abnormally small bilaterally. A recent linkage study [Fisher, S., Vargha-Khadem, F., Watkins, K. E., Monaco, A. P. & Pembry, M. E. (1998) Nat. Genet. 18, 168-170] localized the abnormal gene (SPCH1) to a 5. 6-centiMorgan interval in the chromosomal band 7q31. The genetic mutation or deletion in this region has resulted in the abnormal development of several brain areas that appear to be critical for both orofacial movements and sequential articulation, leading to marked disruption of speech and expressive language.

Cognitive deficits associated with frontal-lobe infarction in children with sickle cell disease

This study examined the cognitive manifestations of frontal-lobe infarction in a population of children with sickle cell disease (SCD). Forty-one patients with SCD underwent MRI. Five patients with stroke symptoms had large infarcts encroaching on the tissue of the frontal lobes. Four patients without symptoms had smaller frontal-lobe infarcts. The patients with stroke were significantly impaired on measures of intelligence, memory, and frontal-lobe function (Wisconsin Card Sorting Test, WCST) compared with both the patients with normal MRI scans (N=30) and a group of sibling controls (N=15), who did not differ from each other. Patients with covert infarction obtained scores on the intelligence tests and the WCST that fell in between those of the stroke patients and the other two groups. This trend toward impairment suggests that patients with covert infarction are at similar risk for cognitive deficits to those with stroke.

Localisation of a gene implicated in a severe speech and language disorder

Between 2 and 5% of children who are otherwise unimpaired have significant difficulties in acquiring expressive and/or receptive language, despite adequate intelligence and opportunity. While twin studies indicate a significant role for genetic factors in developmental disorders of speech and language, the majority of families segregating such disorders show complex patterns of inheritance, and are thus not amenable for conventional linkage analysis. A rare exception is the KE family, a large three-generation pedigree in which approximately half of the members are affected with a severe speech and language disorder which appears to be transmitted as an autosomal dominant monogenic trait. This family has been widely publicised as suffering primarily from a defect in the use of grammatical suffixation rules, thus supposedly supporting the existence of genes specific to grammar. The phenotype, however, is broader in nature, with virtually every aspect of grammar and of language affected. In addition, affected members have a severe orofacial dyspraxia, and their speech is largely incomprehensible to the naive listener. We initiated a genome-wide search for linkage in the KE family and have identified a region on chromosome 7 which co-segregates with the speech and language disorder (maximum lod score = 6.62 at theta = 0.0), confirming autosomal dominant inheritance with full penetrance. Further analysis of microsatellites from within the region enabled us to fine map the locus responsible (designated SPCH1) to a 5.6-cM interval in 7q31, thus providing an important step towards its identification. Isolation of SPCH1 may offer the first insight into the molecular genetics of the developmental process that culminates in speech and language.

Differential effects of early hippocampal pathology on episodic and semantic memory

Global anterograde amnesia is described in three patients with brain injuries that occurred in one case at birth, in another by age 4, and in the third at age 9. Magnetic resonance techniques revealed bilateral hippocampal pathology in all three cases. Remarkably, despite their pronounced amnesia for the episodes of everyday life, all three patients attended mainstream schools and attained levels of speech and language competence, literacy, and factual knowledge that are within the low average to average range. The findings provide support for the view that the episodic and semantic components of cognitive memory are partly dissociable, with only the episodic component being fully dependent on the hippocampus.

Management of childhood craniopharyngioma: can the morbidity of radical surgery be predicted?

Seventy-five children treated for craniopharyngioma between 1973 and 1994 were studied to demonstrate which pre- and intraoperative factors were indicative of a poor outcome as defined by a quantitative assessment of morbidity. This involved a retrospective review of 65 patients and a prospective study of 10 patients focused on clinical details and cranial imaging and a follow-up "study assessment" of 66 survivors performed over the last 2 years. As part of the assessment, 63 patients underwent magnetic resonance imaging with a three-dimensional volume acquisition sequence 1.5 to 19.2 years after initial surgery. Predictors of high morbidity included severe hydrocephalus, intraoperative adverse events, and young age ( < or = 5 years) at presentation. Predictors of increased hypothalamic morbidity included symptoms of hypothalamic disturbance already established at diagnosis, greater height ( > or = 3.5 cm) of the tumor in the midline, and attempts to remove adherent tumor from the region of the hypothalamus at operation. Large tumor size, young age, and severe hydrocephalus were predictors of tumor recurrence, whereas complete tumor resection (as determined by postoperative neuroimaging) and radiotherapy given electively after subtotal excision were less likely to be associated with recurrent disease. Based on these findings, the authors propose an individualized, more flexible treatment approach whereby surgical strategies may be modified to provide long-term tumor control with the lowest morbidity.

Verbal memory impairment after right temporal lobe surgery: role of contralateral damage as revealed by 1H magnetic resonance spectroscopy and T2 relaxometry

We assessed performance on selected tests of verbal memory in 48 patients who had undergone either anterior temporal lobectomy or selective amygdalo-hippocampectomy for the relief of pharmacologically intractable epilepsy. We related performance both to the side of surgical excision and to the presence or absence of abnormalities in the contralateral, unoperated, temporal lobe, as revealed by proton magnetic resonance spectroscopy (1H MRS) or T2 relaxometry. There were abnormalities on the unoperated side detected by 1H MRS in 50% of the 34 patients who successfully underwent spectroscopy, and by T2 relaxometry in 33% of the complete series of 48 patients. There was no systematic relationship between seizure outcome and the presence or absence of abnormalities on the unoperated side. Verbal memory deficits were present in patients with left-sided excision, regardless of whether there were abnormalities on the unoperated side. The patients with right-sided excision also had verbal memory deficits, but only in the group with magnetic resonance abnormalities on the contralateral (ie, left) side and only on delayed recall. The study extends previous findings on the role of the temporal lobes in memory and highlights the role of these new magnetic resonance techniques in relating cognitive processes to brain structures.

Determinants of condom use among intravenous drug users

OBJECTIVE

To examine the factors associated with condom use among a cohort of sexually active intravenous drug users (IVDU).

DESIGN

Data were collected via personal interview at the fourth-month assessment point of a longitudinal study monitoring HIV infection and risk behaviors among IVDU.

SETTING

A community-based methadone clinic.

PARTICIPANTS

A total of 158 sexually active heterosexual male and female IVDU, including both methadone patients and out-of-treatment individuals with a history of opiate abuse.

MAIN OUTCOME MEASURES

We describe a new approach to identify the determinants of condom use. Previous studies have described subjects as either 'condom users' or 'condom non-users', using an individual's overall behavior as the unit of analysis. By analyzing condom use during the most recent sexual encounter, we avoided the problem of interpreting inconsistent condom use. Data were analyzed using forward stepwise logistic regression.

RESULTS

Thirty-four per cent of the heterosexual subjects (n = 160) reported using a condom during their last sexual encounter. Being HIV-positive and having either a causal or commercial partner were each associated with increased probability of using a condom (odds ratio, 10.6, 4.4 and 12.1, respectively). No interactions with sex were found.

CONCLUSIONS

Our results suggest that knowing that one is HIV-positive is an important determinant of condom use; HIV testing may therefore increase the use of condoms. In addition, interventions to change sexual behaviors may need to focus on the type of sexual partner.

High-risk sexual behaviors of intravenous drug users in- and out-of-treatment: implications for the spread of HIV infection

This paper examines the sexual behaviors of 255 intravenous drug users (IVDUs) to assess the potential for the sexual transmission of HIV and to examine differences in sexual behaviors between in- and out-of-treatment IVDUs. In-treatment subjects (N = 152) were a random sample of clients at a large, publicly funded methadone maintenance program. Out-of-treatment subjects (N = 103) were recruited through a chain referral technique, using the in-treatment subjects. Forty-five percent of the study subjects reported multiple partners and 32% reported exchanging sex for money or drugs in the preceding 6 months. Fifty-three percent reported no use of condoms. After controlling for demographic differences between the in- and out-of-treatment groups, out-of-treatment IVDUs reported significantly more partners than in-treatment IVDUs (4.6 vs 2.3, significant t < 0.01), and more often had exchanged sex for money or drugs (44 vs 26%, relative odds 1.8, p < .05). In- and out-of-treatment subjects did not differ with respect to condom use. We conclude that IVDUs both in- and out-of-treatment continue to be at risk of contracting and spreading HIV infection through sexual behaviors, and that being in drug treatment is associated with a lower incidence of high risk sexual behaviors.