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D N Allen

Publications and source records attributed to D N Allen.

26 records · Page 2Linked to original sources
PubMed1997

Utility of WAIS-R short forms in schizophrenia.

Recently, short forms of the Wechsler Adult Intelligence Scale-Revised (Wechsler, 1981) have received increasing attention because of their ability to provide estimated IQ scores with substantial time savings (in some cases 85-90% savings). These short forms may have particular utility for individuals with schizophrenia because they require less time to administer and, as a result, are less taxing for these patients who often exhibit impaired attention and deficient motivation. In this study, we examine the psychometric properties of nine popular WAIS-R short forms in a group of 143 patients diagnosed with schizophrenia. Our results indicated that Kaufman's four subtest short form was the best overall estimator of Full Scale IQ (FSIQ) when a combination of administration time and psychometric properties were considered. However, Ward's seven subtest short form provided the closest estimation of FSIQ and had the lowest misclassification rate, while also providing estimates of Verbal and Performance IQs and yielding 46.5-49.7% time savings. All short forms had substantial misclassification rates, indicating that caution is warranted when using these forms to classify individuals according to standard levels of intellectual functioning (e.g., Average, Low Average, High Average). Clearly, the main consideration in selecting a short form is whether time savings or accuracy have priority.

Adult↗
PubMed1997

Chronic haloperidol treatment does not affect structure of attention in schizophrenia.

Results of a number of investigations indicate attention is a multifactorial construct composed of four distinct cognitive factors including focus-execute, sustain, encode and shift abilities. While investigators have partially or fully replicated this attentional structure in a number of clinical and nonclinical populations, no study has adequately examined the structure of attention in patients with schizophrenia who are not treated with antipsychotics. In this study, we examined the four-factor theory of attention in patients with schizophrenia while they were stabilized on haloperidol (with no adjunctive antiparkinsonian/anticholinergic medications) and again when they were approximately 3 weeks drug free. Standard neuropsychological measures were used to assess attentional functions. Principal components analyses (varimax rotation) of neuropsychological test scores in medicated and drug-free conditions indicated that four factors accounted for 84.2 and 91.8 of total variance in medicated and unmedicated conditions, respectively. Based on these results, it appears that: (1) haloperidol does not appreciably affect structure of the attentional system in patients with schizophrenia; (2) unmedicated patients with schizophrenia exhibit a similar structure of attention as both medicated patients and controls, suggesting that attentional structure is 'normal' in schizophrenia; and (3) the four-factor attention theory is a useful and valid paradigm for evaluating attention in patients with schizophrenia, regardless of medication status.

Adult↗
PubMed1997

Cognitive rehabilitation of chronic alcohol abusers.

The current literature suggests that individuals who chronically abuse alcohol exhibit a wide variety of cognitive deficits resulting from cerebral dysfunction that is either directly or indirectly related to their alcohol consumption history. Cognitive deficits have been hypothesized as having implications for standard alcohol treatment efficacy as they may directly affect cognitively impaired individuals' abilities to utilize various treatment modalities. Although evidence is accumulating that suggests this is actually the case, the majority of alcohol treatment programs neither directly consider the impact cognitive deficits have on treatment efficacy nor do they employ cognitive rehabilitation treatment strategies to remediate identified cognitive deficits. Few studies exist that investigate the remediability of neurobehavioral deficits or the efficacy of integrating cognitive rehabilitation strategies into more traditional treatment programs. Empirical investigations conducted to date indicate that some cognitive deficiencies secondary to alcoholism are amenable to cognitive rehabilitation and this remediation is generalizable. Rigorous well-controlled treatment outcome investigations are needed in order to determine the efficacy of cognitive rehabilitation techniques in naturalistic settings using ecological outcome measures. Also, emphasis should be placed on integrating cognitive rehabilitation techniques with proven efficacy into traditional alcoholism treatment programs.

Alcohol Amnestic Disorder↗
PubMed1994

Reactance theory and alcohol consumption laws: further confirmation among collegiate alcohol consumers.

By the late 1980s, the United States legal drinking age had increased to 21 years. Based on psychological reactance theory, one would predict that these law changes would cause underage collegiate consumers to drink more alcohol because of the belief that their behavioral freedom was being reduced. It was hypothesized that underage collegiate alcohol consumers (UC) would drink more than their legal-age peers (LC) if psychological reactance was a contributing factor to consumption, whereas no differences would be present between the UC and LC groups' usage of illicit drugs, as these had not been affected by recent law changes. To test this hypothesis, a sample of 2,142 college students from 10 midwestern postsecondary educational facilities responded to the Alcohol and Other Drug Use Needs Assessment Survey in the spring of 1990. Mann-Whitney U analyses revealed significant differences between groups on alcohol use measures, but no differences were present on illicit substance use measures. These results are interpreted as supporting reactance theory.

Adolescent↗
PubMed1988

Plasmid-containing strains of Streptococcus mutans cluster within family and racial cohorts: implications for natural transmission.

The transmission of mutans streptococci is thought to occur along familial lines based on investigations which have shown common strains within family units by using phenotypic typing methods, such as bacteriocin production and immunity profiles and serotyping. Difficulties in implementing these typing methods, coupled with conflicting interpretations of results between laboratories, led us to study the conservation of Streptococcus mutans strains within a mother-child cohort by using a genotypic marker, plasmid DNA. Plasmids (all 5.6 kilobases in size) were observed at an overall frequency of 3.3%, with a significantly different frequency in whites (1.5%) compared with blacks (6.6%). Plasmid-containing strains were significantly clustered in mother-child pairs compared with nonrelated individuals (58 versus 3.3%; P less than 0.001). Moreover, the different plasmid groups (I and II) were highly conserved within racial boundaries (P = 0.007). In those instances in which we were able to characterize distinct strains by either biotype or plasmid profile, we found that mothers harbored a more heterogeneous population of mutans streptococci than did their children. This suggested, among other possibilities, that children acquire additional strains as they approach adulthood. Alternatively, we may have been unable to detect more heterogeneity of strains in children because of quantitative differences of strains in saliva. We present collective data which show that strains of S. mutans are highly conserved within not only mothers and their children but also racial groups, suggesting vertical transmission of this organism within human populations. Moreover, we show that levels of S. mutans found in the saliva of the mother correlated with levels found in her child, demonstrating a quantitative relationship within mother-child pairs.

Family↗
PubMed1987

In vitro susceptibilities of suspected periodontopathic anaerobes as determined by membrane transfer assay.

Attempts to devise an antimicrobial approach to combating dentomicrobial infections such as periodontal diseases continue to be hampered by the lack of a relevant in vitro method for determining the susceptibility of suspected periodontopathogens to topically applied antimicrobial agents. Proposed here is a novel in vitro method called the membrane transfer technique, which acknowledges those aspects unique to localized pathogenic infections, particularly those associated with anaerobic bacteria. Bacterial lawns representing six suspected periodontopathic bacteria were prepared on membranes and then placed in contact with different concentrations of antimicrobial agents for 5 min. After incubation for 12 to 24 h, MBCs were determined with the aid of a tetrazolium chloride indicator. Four antimicrobial agents (chlorhexidine, iodine, stannous fluoride, and sodium fluoride) were used to test the applicability of the proposed in vitro method. MBCs were derived for each agent except sodium fluoride against all or most of the six bacterial strains tested. The proposed method may also be useful for examining the bactericidal action of topically applied antimicrobial agents against nonoral infections.

Bacteria, Anaerobic↗
PubMed1985

Distinct bacteriocin groups correlate with different groups of Streptococcus mutans plasmids.

A correlation between the presence of 5.6-kilobase plasmids and bacteriocin activity was found in human-derived strains of Streptococcus mutans. Compared with bacteriocin activity of randomly selected clinical isolates of plasmid-negative strains, bacteriocin activity of plasmid-positive strains significantly inhibited not only two laboratory strains of S. mutans, OMZ176 and AHT (P less than 0.0001 and P = 0.038, respectively), but most plasmid-negative clinical isolates as well (P = 0.0005). Comparisons of inhibition between pairs of plasmid-positive strains revealed two groups, group I and group II, that produced distinct bacteriocins we designated as mutacin I and mutacin II, respectively. Within each group, a strain produced inhibitory activity against all the members of the other group but against no members of its own group. Plasmid DNA from plasmid-positive strains of each group was isolated and analyzed by restriction endonuclease digestion. Plasmids from the two groups that were apparently identical in size differed in digestion patterns for EcoRI, HaeIII, and TaqI, even though six TaqI fragments appeared to be common to all. Based on bacteriocin profiles and restriction enzyme digests, two distinct groups of plasmid-positive S. mutans strains emerged. Although the bacteriocin activity of plasmid-positive strain LM7 (serotype e) placed it in group I, clear differences in restriction digests distinguished it from the other plasmid-containing strains.

Bacteriocins↗