Neuropsychologic impairment and MRI abnormalities associated with chronic solvent abuse

OBJECTIVE

Individuals chronically abusing organic solvents have been reported in the medical literature for almost four decades to have a variety of neurological abnormalities. Most have been single case reports or studies in small numbers of individuals. The purpose of this study was to evaluate the neurologic and neuropsychologic effects of chronic solvent abuse in a larger group of individuals and compare the results to a control group of other drug abusers. Attempts to estimate a dose-response relationship between solvent abuse and either neuropsychological tests or magnetic resonance imaging (MRI) abnormalities were also undertaken.

METHODS

A sample of 55 solvent abusers was compared to a sample of 61 users of other drugs, especially cocaine and alcohol, on a battery of cognitive and neuropsychological tests. Fifty of the solvent abusers and 51 members of the comparison sample also underwent MRI of the brain. Comparisons were made by means of multivariate analysis of variance and covariance.

RESULTS

Compared to the general population, both groups performed poorly, scoring below the mean on most neuropsychological measures. Solvent abusers performed more poorly than the comparison sample on measures of working memory and executive cognitive functions. Both groups showed evidence of abnormal MRI findings, but a greater percentage of the solvent abuse group showed such abnormalities. No clear dose-response relationship was seen between solvent abuse and abnormalities on neuropsychological tests, but a strong dose-response relationship was seen in the presence of MRI abnormalities.

CONCLUSION

The findings in this study document widespread cognitive impairment, which could not be attributed to the effects of solvents entirely. These findings expand upon previous data regarding neurological abnormalities in solvent abusers, by demonstrating a dose-response relationship with MRI abnormalities. An unexpected finding was the high prevalence of neuropsychological impairment and MRI abnormalities among the comparison group. The results of this study has implications regarding low-level solvent exposure, as in the occupational setting, suggesting that MRI may be a more useful tool to sort out the presence of neurological abnormalities rather than neuropsychological tests. Since no dose-response relationship was seen between solvent abuse and neuropsychological testing, reliance upon these tests in assessing neurological injury from solvents is a highly dubious practice.

Memory, neurodynamics, and human relationships

In this article we discuss the implications of the functional organization and dynamics of the brain for understanding human relationships. In particular, we focus on the brain's multiple memory systems and the various roles they play in organizing the interactions of people as they come to know one another. The distinction between the relatively independent declarative, procedural, and emotional learning systems is especially significant in this regard, as the former mediates what we know about one another, the second mediates what we do with one another, and the third affects behavior by altering our emotional state. Knowledge of the functioning of these dissociable memory systems provides a novel perspective on relationships--both ordinary social relationships and those that develop in psychotherapy--and further illuminates psychotherapeutic transference and countertransference phenomena. We begin with a review of the neural basis of these processes, then turn our attention to the interpersonal level of analysis.

Intention tremor, parkinsonism, and generalized brain atrophy in male carriers of fragile X

The authors report five elderly men with the fragile X premutation who had a progressive action tremor associated with executive function deficits and generalized brain atrophy. These individuals had elevated fragile X mental retardation 1 gene (FMR1) messenger RNA and normal or borderline levels of FMR1 protein. The authors propose that elevations of FMR1 messenger RNA may be causative for a neurodegenerative syndrome in a subgroup of elderly men with the FMR1 premutation.

Outcome and utilization differences for older persons with stroke in HMO and fee-for-service systems

OBJECTIVES

To compare treatment and outcomes for older persons with stroke in Medicare health maintenance organizations (HMOs) and fee-for-service (FFS) systems.

DESIGN

Inception cohort stratified by payer and followed for 1 year.

SETTING

Six HMOs and five FFS systems with large Medicare populations in the West, Midwest, and Eastern United States.

PARTICIPANTS

A total of 429 randomly selected stroke patients receiving rehabilitation in nursing homes or rehabilitation hospitals (RHs) from June 1993 to June 1995.

MEASUREMENTS

Improvement in activities of daily living (ADLs) during rehabilitation, and ADL recovery, community residence, and utilization until 12 months after stroke. Outcomes were adjusted for premorbid function, marital status, comorbid illness, posthospital function, cognition, psychological problems, and stroke deficits.

RESULTS

At baseline, HMO patients were more likely to be married, and less likely to be blind or have psychiatric diagnoses. HMO patients had shorter hospitalizations (P < .001), were less likely to be admitted to RHs (13% vs 85%, P < .001), and received fewer therapy and physician specialist visits (P < .001) but more home health visits (P < .001). During rehabilitation, FFS patients made greater improvement in ADLs (difference, 0.73 ADLs; 95% CI, .37-1.09). At 1 year, there was no difference in ADL recovery (difference, -0.24 ADL; 95% CI, -0.64-0.16), but FFS patients were more likely to reside in the community (adjusted OR, 1.8; 95% CI, 1.1-3.1), and HMO patients were more likely to reside in nursing homes (adjusted OR, 2.4; 95% CI, 1.1-5.5).

CONCLUSION

Study findings suggest that short-term functional outcomes and eventual community residence rates are poorer for Medicare HMO patients with stroke than for stroke patients receiving FFS care, consistent with the lower intensity of rehabilitation (in nursing homes vs RHs) and less specialty physician care.

Results of a meta-analysis of cost-benefit research: is this a question worth asking?

We attempted a meta-analysis of telemedicine research studies of the costs associated with telemedicine. First, we performed a search of six well known databases with a variety of relevant keywords. After discarding non-English publications, books and duplicate publications resulting from the same study, we were left with 551 articles for analysis. Our second step was to separate the articles into two groups: those with and those without quantitative cost data. Only 38 articles contained any type of real data. Because many of these 38 studies proved to be inadequately designed or conducted, we were unable to perform a traditional meta-analysis. Furthermore, there were a number of disturbing features common to these studies, including the omission of the number of consultations or patients, almost non-existent longitudinal data collection and lack of uniformity in cost analyses. We conclude that it is premature for any statements to be made, either positive or negative, regarding the cost-effectiveness of telemedicine in general.

Osteoblast numbers after calcitonin therapy: a retrospective study of paired biopsies obtained during long-term calcitonin therapy in postmenopausal osteoporosis

The present study is a retrospective examination of osteoblast indices in human iliac crest bone biopsies from a study on the long-term efficacy of calcitonin. Paired baseline and 2-year biopsies were examined from eight control subjects and 10 treated subjects; treated subjects received 100 MRC units synthetic salmon calcitonin (Calcimar, Armour Pharmaceutical Co, Scottsdale, AZ) injected i.m. sub Q at bedtime. Control patients did not receive a placebo injection. All subjects received 400 units vitamin D(2) p.o. q.d. and 1200 mg CaCO(3) p.o. q.d. When the differences in baseline and 2-year values were analyzed, subjects receiving calcitonin showed no decrease compared with control subjects for the fraction of osteoid surface lined by osteoblasts (ObS/OS) (but were in fact significantly greater, P = 0.04). There was no difference from control subjects in the number of osteoblasts/mm bone surface (NOb/BPm), or mean mineral apposition rate (MAR). Since calcitonin is receiving renewed interest for osteoporosis therapy, these data (derived from paired human biopsies) are valuable since they show that no decrease in osteoblast cell number resulted from long-term calcitonin therapy. Results point to the need for renewed investigation concerning the effect of calcitonin on osteoblast-osteoclast interactions.

Adequate dietary calcium mitigates osteopenia induced by chronic lead exposure in adult rats

The purpose of the present study was to investigate bone changes in the adult rat exposed to low lead levels during intake of normal dietary calcium and to contrast these findings with data from our earlier studies performed with animals receiving low dietary calcium concurrent with lead exposure. The present study exposed adult rats to 100 ppm lead via drinking water for 12 weeks and assessed bone histology, 1,25-dihydroxyvitamin D, 25(OH)vitamin D and parathyroid hormone levels. No osteopenia was evident by quantitative bone histology, and circulating levels of 1,25-dihydroxyvitamin D, 25(OH) vitamin D and parathyroid hormone were normal. Bone ash findings documented incorporation of significant amounts of lead into bone mineral. These findings document absence of interference with vitamin D metabolism, absence of secondary hyperparathyroidism and absence of osteopenia following 12 weeks of low lead exposure in the adult rat maintained on normal calcium intake. Results stress the importance of adequate calcium intake in our elderly population who may be exposed to cumulative, low-level lead exposure.

Rural telemedicine: a national snapshot

OBJECTIVES

To estimate the use of telemedicine in rural hospitals in the U.S. and to identify and describe those rural hospitals that are active in telemedicine.

MATERIALS AND METHODS

Nationwide mailed survey, with telephone follow-up, to all hospitals not located in a Metropolitan Statistical Area.

RESULTS

The overall response rate was 95% of all rural hospitals. Of these, 416 (17.55%) reported having telemedicine, and more than 530 more have plans to begin telemedicine programs during the next few years. Rural hospitals of all sizes and in all regions of the country are initiating telemedicine programs, but there is significant variation by region. Specifically, hospitals located in more populous rural counties near metropolitan areas are less likely to have telemedicine than are hospitals located in less populous rural counties in more remote areas. Conservatively, more than 4000 teleconsults per month are estimated among rural hospitals nationwide in 1995, including all forms of telemedicine.

CONCLUSIONS

Telemedicine is becoming an important means of providing specialty medical services in rural areas. This screening survey generated information about the extent of telemedicine use in rural communities, but it also raised many new questions. These questions are being pursued through a detailed follow-up survey.

Rural applications of telemedicine

OBJECTIVES

To describe the status of telemedicine in rural America, the characteristics of health care facilities using telemedicine technologies to serve rural patients, the volume and scope of services delivered, the costs associated with this care, and the funding sources.

METHODS

A screening survey was mailed to all 2472 nonfederal U.S. hospitals located outside metropolitan areas. Nonrespondents were interviewed by telephone. Those who reported some form of telemedicine capability, and all the telemedicine affiliates they named, became the sample for a detailed follow-up survey (N = 558) in January 1996.

RESULTS

Ninety-six per cent of all rural hospitals responded to the screener survey, and 89% of the 558 identified telemedicine facilities responded to the detailed follow-up survey (total respondents = 499). In this cross-sectional study, two thirds of the telemedicine respondents (340) were using only teleradiology. Of the 159 telemedicine programs pursuing other clinical applications, 67% had been using telemedicine for 2 years or less. Telemedicine facilities have tried many clinical specialty applications, the most common being radiology, cardiology, and orthopedics. At this early stage of technology diffusion, reported utilization of the telemedicine systems for both clinical and nonclinical applications was very low, and the unit costs of equipment acquisition and operating expenses were corresponding high. Programs most commonly used hospital financial resources and federal grants and contracts for support. Telemedicine networks planned to grow from an average of nine facilities to an average of 13 facilities during 1996.

CONCLUSIONS

Investment has been rapid in telemedicine, and the installed base reported in this survey was large, sophisticated, and growing rapidly. Nonclinical uses of the technology (e.g., meetings, training sessions, continuing medical education) were more common than clinical consultations, although the volumes of both were quite low. Investment and expansion to new sites were occurring in the absence of a favorable payor reimbursement environment and in spite of low volume at most operating sites, demonstrating optimism about the future of telemedicine and the potential for nonclinical applications.

Analytic framework for evaluation of telemedicine

This paper discusses two conceptual models intended to facilitate research on the effects and effectiveness of telemedicine. The first is a conceptual framework to study the efficacy of telemedicine as a diagnostic medium. Using conditions that are carefully chosen to serve as indicators of effectiveness, we recommended the analysis of sensitivity and specificity to establish the accuracy of telemedicine in relation to conventional health care delivery. Suggested guidelines for interpretation of the results are discussed. The second model is a scheme for classification of telemedicine applications that is based on processes of care rather than on specialties or disorders. The purpose of this classification scheme is to facilitate research on such variables as costs, access, acceptability, and effects on practice patterns.

Telemedicine: where it is and where it's going

The term telemedicine encompasses a wide range of telecommunications and information technologies and many clinical applications, although interactive video may be the most common medium. The first telemedicine programs were established almost 40 years ago, but the technology has grown considerably in the past decade. Despite the expansion of telemedicine, the volume of patients receiving services that use the technology remains relatively low (about 21000 in 1996). In part, this reflects the lack of a consistent coverage and payment policy and concerns about licensure, liability, and other issues. A considerable amount of federal funding has supported telemedicine in recent years, and legislators and federal, regional, and state policymakers are struggling with several crucial policy matters. Research on the effectiveness of telemedicine is somewhat limited, although the work that has been done thus far supports the hypothesis that, in general, the technology is medically effective. The cost-effectiveness of specific telemedicine applications has not yet been rigorously demonstrated.

Higher instrumental activities of daily living disability in Hispanics compared with non-Hispanic whites in rural Colorado. The San Luis Valley Health and Aging Study

This study examined Hispanic versus non-Hispanic white patterns of needing assistance with instrumental activities of daily living (IADL). The authors interviewed 798 Hispanic and 614 non-Hispanic white residents of rural Colorado, who were aged 60 years and older between 1993 and 1995. Seventy-five participants were nursing home residents at the time of the interview. Community-dwelling Hispanics were 1.6 times as likely as non-Hispanic whites to need assistance with at least one IADL task (95% confidence interval 1.25-2.13). A larger proportion of disabled non-Hispanic whites were in nursing homes but, after including nursing home residents, Hispanics remained significantly more likely to need assistance on at least one IADL task (odds ratio = 1.49, 95% confidence interval 1.16-1.93). Hispanics were also more likely to have difficulty on observed performance tasks. The Hispanic excess was not removed by adjusting for chronic disease, reported difficulty walking, or income. English language proficiency adjustment lowered the Hispanic excess, but adjusting for years of education or Mini-Mental State Examination scores more completely removed the ethnic differences. Higher education was protective for both Hispanic and non-Hispanic white elderly. Efforts to further investigate what facets or correlates of education are operating may offer useful insights into limiting IADL difficulties in future cohorts.