Twitter-based measures of neighborhood sentiment as predictors of residential population health

Several studies have recently applied sentiment-based lexicons to Twitter to gauge local sentiment to understand health behaviors and outcomes for local areas. While this research has demonstrated the vast potential of this approach, lingering questions remain regarding the validity of Twitter mining and surveillance in local health research. First, how well does this approach predict health outcomes at very local scales, such as neighborhoods? Second, how robust are the findings garnered from sentiment signals when accounting for spatial effects? To evaluate these questions, we link 2,076,025 tweets from 66,219 distinct users in the city of San Diego over the period of 2014-12-06 to 2017-05-24 to the 500 Cities Project data and 2010-2014 American Community Survey data. We determine how well sentiment predicts self-rated mental health, sleep quality, and heart disease at a census tract level, controlling for neighborhood characteristics and spatial autocorrelation. We find that sentiment is related to some outcomes on its own, but these relationships are not present when controlling for other neighborhood factors. Evaluating our encoding strategy more closely, we discuss the limitations of existing measures of neighborhood sentiment, calling for more attention to how race/ethnicity and socio-economic status play into inferences drawn from such measures.

Long-term cognitive and school outcomes of late-preterm and early-term births: a systematic review

BACKGROUND

Children born before full term (39-41 weeks' gestation) are at increased risk of adverse cognitive outcomes. Risk quantification is important as late-preterm (LPT; 34-36 weeks) and early-term (ET; 37-38 weeks) births are common.

METHOD

This review analyses the effect of LPT and ET births on long-term cognitive and educational outcomes. The primary outcome was general cognitive ability. Secondary outcomes included verbal/non-verbal intelligence quotient, subject-specific school performance and special educational needs. The search strategy included Medline and Embase from January 1975 to June 2013. Eligible studies investigated specified outcomes and included suitable gestational age participants assessed at 2 years and older. Outcome measures and socio-demographic descriptors were extracted, and data meta-analysed where possible.

RESULTS

Eight studies compared ET birth with full-term birth. Fourteen studies compared LPT birth with either term birth (>37 weeks, n = 12 studies) or full-term birth (39-41 weeks, n = 2 studies). Substantial between-study heterogeneity existed. LPT and ET children underperformed in most outcomes compared with their term/full-term counterparts, respectively. For example, LPT children had an increased risk of lower general cognitive ability (adjusted risk ratio 1.38 [95% confidence interval 1.06-1.79]), and full-term children performed 5% of a standard deviation higher (z-score 0.05 [0.02, 0.08]) than ET children. Poorer outcomes persist into adulthood; term cohorts performed 5% of a standard deviation higher than LPT cohorts (z-score 0.05 [0.04, 0.07]), and full-term cohorts performed 3% of a standard deviation higher than ET cohorts (z-score 0.03 [0.02, 0.04]).

CONCLUSION

This review critically examines the knowledge around long-term cognitive outcomes of LPT and ET births, demonstrating multiple, small, adverse differences between LPT/ET and term/full-term births.

Computational Lexical Analysis of the Language Commonly Used to Describe Gout

OBJECTIVE

To characterize the current language that is used in describing and defining gout, its symptoms, and its treatment by reviewing recent publications in rheumatology and determining how word choice may, or may not, be reflective of recent scientific developments in gout specifically.

METHODS

This was a computational linguistics study, using collocations analyses and concordance analyses on a database of scientific literature related to gout. The final data set for analysis included 2,590 articles, all relating to gout and published between May 2003 and May 2013 and amounting to 12,101,036 tokens (sentence segments). Analysis was conducted by a team of linguists and social scientists.

RESULTS

Our primary finding is that current disease language in gout is marked by ambiguity and imprecision, as evidenced by numerous terms that have similar but distinct meanings, but are nevertheless used interchangeably, therefore blending the slight but significant distinctions between these words. Whereas treatment language is characterized by a multitude of terms to describe a therapeutic mechanism of action, there is a relative void of terms and phrases used to describe success (treating to target) in gout.

CONCLUSION

The data suggest that the language used to describe gout could be improved and updated. A transformation from an antiquated and insufficiently descript terminological set to one that reflects the recent scientific and clinical advancements made in the category would maximize opportunities for patient and physician understanding.

Dehydroepiandrosterone (DHEA) supplementation for cognitive function in healthy elderly people

BACKGROUND

In view of the theoretical possibility of beneficial effects of DHEA or DHEAS in retarding age-associated deterioration in cognitive function, we have reviewed studies in this area.

OBJECTIVES

To establish whether administration of DHEA, or its sulphate, DHEAS, improves cognitive function or reduces the rate of decline of cognitive function in normal older adults.

SEARCH STRATEGY

Trials were identified from a last updated search of the Specialized Register of the Cochrane Dementia and Cognitive Improvement Group on 10 October 2005 using the terms dhea*, prasterone, dehydroepiandrosterone*. In addition MEDLINE, EMBASE, PsycINFO and CINAHL were searched to find trials with volunteers who had no or minor memory complaints. Relevant journals, personal communications and conference abstracts were searched for randomized controlled trials investigating the effects of DHEA/S on cognition in older adults.

SELECTION CRITERIA

All randomized placebo-controlled trials enrolling people aged over 50 without dementia and to whom DHEA/S in any dosage was administered for more than one day were considered for inclusion in the review.

DATA COLLECTION AND ANALYSIS

Data for the specified outcomes were independently extracted by two reviewers (JGE and RM) and cross-checked. Any discrepancies were discussed and resolved. No data pooling was undertaken owing to the lack of availability of the relevant statistics.

MAIN RESULTS

Only three studies provided results from adequate parallel-group data. Barnhart 1999 enrolled perimenopausal women with complaints of decreased well-being and, using three cognitive measures, found no significant effect of DHEA compared with placebo at 3 months. Wolf 1998b enrolled 75 healthy volunteers (37 women and 38 men aged 59-81) in a study of the effect of DHEA supplements on cognitive impairment induced by stress; after two weeks of treatment, placebo group performance deteriorated significantly on a test of selective attention following a psychosocial stressor (p<0.05), while deterioration was not evident in the DHEA group (p=0.85). However, when compared with placebo, DHEA was associated with a significant impairment on a visual memory recall test (p<0.01) following the stressor. No significant effects were found on a third cognitive task. Effects were not found on tasks when administered in the absence of a stressor. van Niekerk 2001 found no effect on cognitive function in 46 men aged 62-76 from three months of DHEA supplementation. DHEA supplements were well tolerated and without significant adverse effects apart from the reduced performance in the visual memory recall test observed in one trial.

AUTHORS' CONCLUSIONS

What little evidence there is from controlled trials does not support a beneficial effect of DHEA supplementation on cognitive function of non demented middle-aged or elderly people. There is no consistent evidence from the controlled trials that DHEA produces any adverse effects. In view of growing public enthusiasm for DHEA supplementation, particularly in the USA, and the theoretical possibility of long-term neuroprotective effects of DHEA/S, there is a need for further high quality trials in which the duration of DHEA treatment is longer than one year, and the number of participants is large enough to provide adequate statistical power.

Donepezil for vascular cognitive impairment

BACKGROUND

Vascular disease is the second commonest cause of dementia after Alzheimer's disease. There are difficulties in classifying patients with this type of cognitive impairment owing to varied clinical presentation and different types of arterial disease. There is some degree of overlap in the neuropathology of Alzheimer's and vascular dementia. Deficient cholinergic neurotransmission, a characteristic of Alzheimer's disease, has been postulated to contribute to the cognitive impairment of vascular disease of the brain. Cholinesterase inhibitors, such as donepezil, may therefore be a rational treatment.

OBJECTIVES

To assess the clinical efficacy and tolerability of donepezil on cognitive function, clinical global impression, activities of daily living and social functioning of people with vascular cognitive impairment.

SEARCH STRATEGY

Relevant randomized controlled trials were identified from a search of the Cochrane Dementia and Cognitive Improvement Group Specialized Register on 21 July 2003 using the terms donepezil, E2020 and Aricept. This Register consists of records from all major healthcare databases and many ongoing trials databases. Unpublished trials were requested from the drug company Eisai Inc and they provided us with the required data.

SELECTION CRITERIA

All unconfounded randomized double-blind trials comparing donepezil with placebo were eligible for inclusion. Trials using combinations of donepezil with other pharmacological interventions were excluded.

DATA COLLECTION AND ANALYSIS

Both reviewers assessed studies against the criteria for inclusion and extracted data. Data were pooled where appropriate, and weighted mean differences or Peto odds ratios with 95% confidence intervals calculated. Intention-to-treat analysis was undertaken when possible.

MAIN RESULTS

Two large-scale, randomized, double-blind, parallel-group controlled trials were identified for inclusion. A total of 1219 people with mild to moderate cognitive decline due to probable or possible vascular dementia (according to the NINCDS/AIREN criteria and the Hachinski Ischemia Scale) were recruited. Donepezil, at doses of 5 or 10 mg a day was compared with placebo for 24 weeks. For each outcome measure, mean change from baseline at weeks 12 and 24, using a last observation carried forward analysis, was calculated. Cognitive function: The donepezil groups showed statistically significantly better performance than the placebo groups on the cognitive subscale of the Alzheimer's Disease Assessment Scale (ADAS-Cog) at 12 and 24 weeks. The donepezil groups produced statistically significantly better scores than the placebo groups on the Mini-Mental State Examination (MMSE) at 12 and 24 weeks. Global function: The sum of the boxes of the Clinical Dementia Rating (CDR-SB) showed at 24 weeks a statistically significant benefit of 10 mg donepezil daily over both placebo and a 5 mg daily dosage. The Clinician's Interview-Based Impression of Change-plus version (CIBIC-plus) showed improved global function of participants taking 5 mg of donepezil daily compared with the placebo group but this was not seen in the higher dose group. Activities of daily living and social behaviour: On the Instrumental Activity of Daily Living (IADL) scale, there was no statistically significant difference between the groups taking donepezil 5mg per day donepezil and placebo, but the group taking 10 mg of donepezil a day showed benefit compared with placebo There were statistically significant benefit for donepezil at either dosage compared with placebo on the Alzheimer's Disease Functional Assessment and Change Scale (ADFACS). Tolerability and adverse effects: Broad range of adverse events were reported in the studies and data confirmed that donepezil was well tolerated, and most of the side effects were transient and were resolved by stopping the medication. Some of these events, especially nausea, diarrhoea, anorexia and cramp appeared more frequently on the 10 mg dose where there was a statistically significant difference compared with placebo. Drop-out: The drop-out rate was similar between the groups, 84.2% (330) patients completed the studies. The withdrawal rate was low and due mainly to side effects.

REVIEWER'S CONCLUSIONS

Evidence from the available studies support the benefit of donepezil in improving cognition function, clinical global impression and activities of daily living in patients with probable or possible mild to moderate vascular cognitive impairment after 6 months treatment. Extending studies for longer periods would be desirable to establish the efficacy of donepezil in patients with advanced stages of cognitive impairment. Moreover, there is an urgent need for establishing specific clinical diagnostic criteria and rating scales for vascular cognitive impairment.

Vitamin B12 for cognition

BACKGROUND

An association between neuropsychiatric disorders and vitamin B12 deficiency has been recognized since 1849 when pernicious anaemia was first described. It has been suggested that deficiency of vitamin B12 might contribute to age-associated cognitive impairment. Low serum vitamin B12 concentrations are found in more than 10% of older people. A high prevalence of low serum vitamin B12 levels, and other indicators of vitamin B12 deficiency have been reported among people with Alzheimer's disease. A review is needed of trials assessing effects of vitamin B12 supplementation on cognitive function in later life.

OBJECTIVES

To examine the effect of B12 supplementation on cognitive function of demented and elderly healthy people in terms of preventing the onset or progression of cognitive impairment or dementia.

SEARCH STRATEGY

The trials were identified from a search of the Specialized Register of the Cochrane Dementia and Cognitive Improvement Group on 12 September 2002 using the terms listed in additional table 1. In addition MEDLINE 1966 to 2002/09 and EMBASE 1980-2002/08 were searched using the same terms and cognit* to pick up studies with healthy volunteers.

SELECTION CRITERIA

All randomized double-blind trials in which vitamin B12 at any dose was compared with placebo.

DATA COLLECTION AND ANALYSIS

Both reviewers applied the selection criteria to assess the quality of the studies. One reviewer collated and analysed the data. For each outcome measure data were sought on every patient randomized.

MAIN RESULTS

From the two included studies (Seal 2002; Fourniere 1997) of people with dementia and low serum vitamin B12 levels, there was no statistically significant evidence of treatment effect, vitamin B12 supplementation compared with placebo, on cognitive function.

REVIEWER'S CONCLUSIONS

Evidence of any efficacy of vitamin B12 in improving the cognitive function of people with dementia and low serum B12 levels is insufficient. The two trials of acceptable methodology (Fourniere 1997; Seal 2002) were restricted to a small number of patients with Alzheimer's disease and other types of cognitive impairment. No trials involving people without dementia or using other definitions of vitamin B12 deficiency were found.

The effect of vitamin B6 on cognition

BACKGROUND

Micronutrient status can affect cognitive function at all ages. Vitamin deficiencies could influence memory function and might contribute to age-associated cognitive impairment and dementia. Vitamin B6, comprising three chemically distinct compounds pyridoxal, pyridoxamine, and pyridoxine, is involved in the regulation of mental function and mood. Vitamin B6 is also an essential homocysteine re-methylation cofactor, and deficiency is associated with increase in blood homocysteine levels. Homocysteine is a risk factor for cerebrovascular disease and may also have directly toxic effects on neurons of the central nervous system. Neuropsychiatric disorders including seizures, migraine, chronic pain and depression have been linked to vitamin B6 deficiency. Epidemiological studies indicate that poor vitamin B6 status is common among older people. Hyperhomocysteinaemia has been suggested as a cause or mechanism in the development Alzheimer's disease and other forms of dementia. Supplementation with B vitamins including vitamin B6 has been shown to reduce blood homocysteine levels.

OBJECTIVES

To assess the efficacy of vitamin B6 supplementation in reducing the risk of developing cognitive impairment by older healthy people, or improving cognitive functioning of people with cognitive decline and dementia, whether or not vitamin B6 deficiency has been diagnosed.

SEARCH STRATEGY

The Specialized Register of the Cochrane Dementia and Cognitive Improvement Group was searched on 20 May 2003 using the terms: vitamin B6, pyridoxine, pyridoxamine, pyridoxal. For relevant trials on healthy elderly people MEDLINE, EMBASE and CENTRAL were searched using the previously mentioned terms as well as the term cognit *

SELECTION CRITERIA

All unconfounded, double-blind randomized controlled trials in which the intervention with vitamin B6 was compared with placebo for healthy older people or people with cognitive decline or dementia. The primary outcome of interest was the efficacy of vitamin B6 supplementation on cognitive function.

DATA COLLECTION AND ANALYSIS

The two reviewers independently evaluated all studies identified as possibly meeting the criteria for inclusion. One reviewer independently extracted the data. Studies were rated for their overall quality. The weighted mean differences between treatment and placebo groups, with 95% confidence intervals, were calculated for each outcome. Review Manager version 4.2 was used to analyse the variance.

MAIN RESULTS

No trials of vitamin B6 involving people with cognitive impairment or dementia were found. The two trials included in the review (Bryan 2002; Deijen 1992) used a double-blind, randomized, placebo-controlled design and involved 109 healthy older people. One trial restricted enrolment to women and the other to men. Vitamin B6 supplementation and healthy older women: Bryan 2002 enrolled 211 healthy women from various age groups into a 5-week study. The trial was of multifactorial design with folic acid, vitamin B12, vitamin B6 and placebo in its four arms. Twelve healthy women aged 65 to 92 years received 75 mg vitamin B6 orally per day and were compared with 21 healthy women who were allocated to placebo. No statistically significant benefits from vitamin B6 on mood or cognition were observed. Vitamin B6 supplementation and healthy older men: Deijen 1992 recruited 76 healthy men aged 70 to 79 years. They were divided into 38 matched pairs, one member of each pair randomly allocated to 20 mg of vitamin B6 (pyridoxine hydrochloride) per day for 12 weeks the other to placebo. No statistically significant differences between treatment and placebo were found in their effects on cognition or mood. Effect of vitamin B6 supplementation on vitamin B6 status: Deijen 1992 reported that 20 mg of pyridoxine hydrochloride per day for 12 weeks increased blood vitamin B6 activity as assessed as by plasma pyridoxal-5'-phosphate (WMD 238, 95%CI 211.58 to 264.42, P<0.00001) and erythrocyte enzyme asparate aminotransferase (WMD 0.43, 95%CI 0.30 to 0.56, P<0.00001). Effect of vitamin B6 supplementation on blood homocysteine concentration: Neither of the included trials measured homocysteine levels. Drop-outs: All participants allocated to vitamin B6 or placebo completed the trial protocol. Adverse Events: No adverse effects were reported. Effect of vitamin B6 on carer burden, care costs and institutionalization rate: We found no trials in which these outcomes were assessed.

REVIEWER'S CONCLUSIONS

This review found no evidence for short-term benefit from vitamin B6 in improving mood (depression, fatigue and tension symptoms) or cognitive functions. For the older people included in one of the two trials included in the review, oral vitamin B6 supplements improved biochemical indices of vitamin B6 status, but potential effects on blood homocysteine levels were not assessed in either study. This review found evidence that there is scope for increasing some biochemical indices of vitamin B6 status among older people. More randomized controlled trials are needed to explore possible benefits from vitamin B6 supplementation for healthy older people and those with cognitively impairment or dementia.

Neurological correlates of fetal cocaine exposure: transient hypertonia of infancy and early childhood

OBJECTIVE

To assess whether prenatal cocaine exposure has any long-term effects on neurodevelopment.

DESIGN

A prospective cohort study with examiners blind to drug exposure and human immunodeficiency virus (HIV) status.

SUBJECTS

Of 144 high-risk infants enrolled in a perinatal HIV neurodevelopmental study, 119 (83%) infants with both neurological and urine toxicology measures were followed up to age 24 months.

METHODS

Neurological and developmental assessments were analyzed at 6-month intervals grouped according to the presence of cocaine in urine toxicology: 51 infants were cocaine-positive. Adjusted odds ratios (ORs) and 95% confidence interval (CI) were obtained by logistic regression equations that adjusted for perinatal variables, including measures of fetal growth, gestation, HIV status, and infant toxicology results.

SETTING

Harlem Hospital Center from 1988 to 1992.

RESULTS

At age 6 months, 21 of 51 (41%) cocaine-positive children exhibited hypertonia of any type (hypertonic tetraparesis, hypertonic diparesis, and hypertonic hemiparesis) compared with 17 of 68 (25%) cocaine-negative infants (OR = 2.1, CI = 1.0-4.6). Cocaine-positive infants were four times more likely to show hypertonic tetraparesis (HTP) than cocaine-negative infants (OR = 4.0; CI = 1.5-10.8). The association remained significant in multivariate analyses. Hypertonia, consistent with cerebral palsy, diminished over time in both groups. In 97% of affected infants hypertonia resolved by 24 months. Arm hypertonia abated first; leg hypertonia remained in some children up to age 18 months. No differences in development scores between cocaine-positive and cocaine-negative were noted at any age interval. However, among cocaine-positive infants those with early HTP showed significantly lower mean developmental scores at 6 and 12 month compared to infants without HTP.

CONCLUSION

Cocaine positivity urine toxicology at birth is associated with hypertonia during infancy. Such cocaine-induced effects are usually symmetrical, transient, and the majority of exposed children outgrow hypertonia by 24 months of life. Among cocaine-positive infants, HTP may be a marker for later developmental impairments.

Risk of human immunodeficiency virus type 1-related neurologic disease in a cohort of intravenous drug users

BACKGROUND

Although the proportion of cases of acquired immunodeficiency syndrome related to intravenous drug use has increased dramatically over the past decade, there has been no longitudinal examination of primary neurologic disease in this group.

OBJECTIVE

To study the development of neurologic disease in human immunodeficiency virus (HIV)-negative and HIV-positive men and women who were intravenous drug users over a 3.5-year period.

DESIGN

Prospective observational cohort study.

SETTING

Subjects were recruited from an infectious disease clinic at a New York City Hospital or from a methadone maintenance program.

PARTICIPANTS

Ninety-nine HIV-negative (62 men and 37 women) and 124 HIV-positive (85 men and 39 women) intravenous drug users volunteered.

MAIN OUTCOME MEASURE

The development of clinically significant manifestations in six neurologic domains.

RESULTS

With multivariate adjustment for current and past substance abuse, age, education, and head injury, we examined the odds of developing HIV-related neurologic disease. Extrapyramidal signs and reduced motor ability became increasingly apparent over time in HIV-infected men as their CD4 cell count declined and as the subjects developed the acquired immunodeficiency syndrome. Fewer neurologic signs were seen in the women.

CONCLUSIONS

The impact of HIV infection among intravenous drug users parallels that in homosexual men and is independent of alcohol and other drug use.

Neurologic and neuropsychological manifestations of human immunodeficiency virus infection in intravenous drug users without acquired immunodeficiency syndrome. Relationship to head injury

We examined 99 human immunodeficiency virus (HIV)-negative and 122 HIV-positive intravenous drug users (IVDUs) without acquired immunodeficiency syndrome (AIDS) to determine whether HIV-positive IVDUs had more neurologic and neuropsychological impairment than their HIV-negative counterparts. Controlling for age, education, drug use, history of head injury, and interactions between head injury and HIV status and drug use, HIV-positive subjects had more extrapyramidal signs and frontal release signs. These findings persisted when asymptomatic HIV-positive subjects without systemic signs of infection and HIV-negative subjects were compared. Neurologic findings were more severe in those with more systemic illness. Among those reporting a history of head injury with loss of consciousness, neuropsychological performance was significantly worse in the HIV-positive subjects, and this increased with severity of illness. This was not true in the group without head injury, suggesting an interaction between history of head injury and the seropositive state. No relationship was noted between head injury and either drug use or HIV state. Therefore, subtle neurologic and neuropsychological abnormalities may precede clinical evidence of AIDS in IVDUs and may be more evident in those with head injury.

A prospective controlled study of magnetic resonance imaging of the brain in gay men and parenteral drug users with human immunodeficiency virus infection

To detect the earliest structural changes in the brain in human immunodeficiency virus (HIV) infection, 118 gay men and 115 parenteral drug users enrolled in a study of the natural history of HIV infection underwent magnetic resonance imaging evaluations. Routine T2-weighted and heavily T2-weighted scans for quantification of brain water were obtained, blinded to HIV serostatus. Atrophy and foci of increased signal did not correlate with any medical, immunologic, neurologic, or neuropsychologic parameters in the group as a whole, or in the gay men or parenteral drug user subgroups. Three subjects had progressive multifocal leukoencephalopathy and one had central nervous system lymphoma. In a subgroup in whom intracranial water percent was calculated, correlations were found with CD4 counts and CD4/CD8 ratios. We conclude that standard magnetic resonance imaging of the brain does not differentiate asymptomatic and mildly symptomatic HIV-positive individuals from HIV-negative individuals, regardless of risk group. However, intracranial water percent may distinguish HIV-positive from HIV-negative individuals because it correlates with raw CD4 counts and CD4/CD8 ratios.

Neurologic disease in human immunodeficiency virus-infected drug abusers

Previous studies of human immuno-deficiency virus-related neurologic disease have been either retrospective or have included mostly homosexual patients. We sought to determine (1) the true prevalence of neurologic abnormalities in patients with acquired immunodeficiency syndrome or lymphadenopathy acquired immunodeficiency-related complex, and (2) whether differences in prevalence or type of neurological abnormality exist between parenteral drug abusers and non-parenteral drug abusers. We prospectively evaluated 190 adult inpatients with either acquired immunodeficiency syndrome (129) or lymphadenopathy acquired immunodeficiency-related complex (61); 151 (80%) were parenteral drug abusers, and 172 patients (91%) had neurologic symptoms or signs. There was no significant difference in prevalence of neurologic disease between parenteral drug abusers and non-parenteral drug abusers, or between patients with acquired immunodeficiency syndrome and those with lymphadenopathy acquired immunodeficiency-related complex. The prevalence of neurologic symptoms in these patients with lymphadenopathy acquired immunodeficiency-related complex and acquired immunodeficiency syndrome is the highest reported to date and appears to reflect the prospective nature of the study.

Hypoglycemia: causes, neurological manifestations, and outcome

During a 12-month prospective study there were 125 visits to the Harlem Hospital Emergency Room for symptomatic hypoglycemia. Sixty-five patients had obtundation, stupor, or coma; 38 had confusion or bizarre behavior; 10 were dizzy or tremulous; 9 had had seizures; and 3 had suffered sudden hemiparesis. Diabetes mellitus, alcoholism, and sepsis, alone or in combination, accounted for 90% of predisposing conditions; others included fasting, terminal cancer, gastroenteritis, insulin abuse, and myxedema. Average blood glucose levels were lower among comatose than among obtunded patients, but overlap was considerable, and overall there was little correlation among cause, blood glucose levels, and symptoms. Although mortality was 11%, only one death was attributable to hypoglycemia per se, and only four survivors had focal neurological residua.

Occurrence of Gas-Bubble Disease in Three Species of Bivalve Molluscs

Gas-bubble disease was observed in adult oysters and hard clams held in heated running sea water during the winter. Heating the cold sea water in closed heat exchangers caused it to become supersaturated with atmospheric gases. Exposure of the animals to this water caused the formation of gas-filled conchiolin blisters on the valves of the oysters. Bubbles of gas were observed in the gill filaments of the oysters and clams and in the mantle tissue of the oysters. Any method, such as the use of baffles or an aerated head tank, that reduces the dissolved gas concentration in the water will help prevent the disease.