Dopamine agonists have been used with some success in treating cocaine addiction. However, both cocaine and psychostimulants have been reported to produce neurotoxic effects. We evaluated the effect of the stimulant diethylpropion on cognitive performance in a double-blind, placebo-controlled trial. Forty-six abstinent crack-cocaine users received either placebo, 25-mg, 50-mg, or 75-mg doses of diethylpropion. Patients were tested at baseline and again after 9-14 days of medication. There were no differences between placebo and medication groups on any test, indicating that, within the time frame studied, diethylpropion does not produce neurotoxic effects that can be detected with standardized neuropsychological tests.

The Wide Range Achievement Test (Revised) (WRAT-R) reading test, demographic variables and drug use severity were used to develop prediction equations to estimate premorbid ability in 92 cocaine abusers. WRAT-R reading was correlated significantly with full scale, verbal and performance IQ. Stepwise regression indicated that only WRAT-R reading score and age accounted for 23% of the variance in Full Scale IQ (FSIQ) and 28% in Verbal IQ (VIQ). Abstinence and severity of use variables did not correlate with nor predict IQ. Actual and predicted IQ scores were correlated significantly and did not differ based on within group t-tests. Thus, these formulas accurately estimate premorbid functioning in cocaine-dependent research patients with FSIQs in the average to low average range, replicating the results in normal adults with average IQs.

The authors evaluated the psychometric properties of a 33-item Likert-scale questionnaire assessing subcomponents of craving in 77 crack-cocaine abusers. Split-half and test-retest correlations were moderate to strong, indicating good internal reliability. High correlations with traditional visual analog scale measures of drug thoughts and cravings (but not other symptoms) support the questionnaire's validity as a measure of subjective craving. An exploratory factor analysis indicated that craving in these treatment-seeking crack-cocaine abusers is motivated both by the positive reinforcing properties of cocaine and by seeking relief from negative symptoms. A previous study using a similar questionnaire found that craving in non-treatment-seeking drug users was motivated primarily by the desire and intention to use cocaine. The results support the notion that subcomponents of craving exist and may vary with motivational state (i.e., those in treatment vs. non-treatment-seekers).

HOFF, ANNE L. PHD; SHUKLA, SASHI MD; HELMS, PAUL MD; ARONSON, THOMAS A. MD; LOGUE, CAMILLE PHD; OLLO, CHRISTINE PHD; COOK, BRIAN DO Author Information

30 inpatients diagnosed with schizophrenia were compared to 35 inpatients with bipolar affective disorder, manic type, on a large group of neuropsychological measures. Separate factor analyses were performed on measures of verbal, spatial, and speed variables in order to generate summary scales. Controlling for the effects of age, education, sex, duration of illness, number of previous hospitalizations, and medications at time of testing, there were no significant differences between diagnostic groups on the three factors or on individual test variables. Patients on medication performed more poorly on speed variables than those off medication. These findings call into question the notion of differential patterns of cognitive deficit among psychotic diagnoses.

In previous reports we have suggested that the auditory brain-stem responses (ABRs) of adults with Down's syndrome exhibit two abnormalities unique to that population: a shortened central conduction time and an insensitivity of peak latencies to increases in stimulation rate. The current experiment assessed the possibility that these abnormalities were caused by hearing deficit rather than central auditory dysfunction. The ABRs of a group of adults with Down's syndrome were compared with those of a group of non-Down retarded and a control group of nonretarded adults. An audiometric examination consisting of pure-tone audiograms, tympanometry, and acoustic reflexes was given to all the retarded subjects. The incidence of serious hearing deficit in the Down's syndrome group was 73% compared to 22% in the non-Down retarded. Regardless of hearing status, the central conduction times in the Down group were shorter than in either of the other groups. The abnormal response to stimulation rate, however, was found to reflect high-frequency hearing loss and not central auditory dysfunction. The data suggest that a battery of objective tests including tympanometry, acoustic reflexes, and selected ABR measures may be useful in identifying hearing deficit in both Down-syndrome and non-Down retarded individuals.

The cellular and cytoarchitectural features of the lateral superior olive, the medial superior olive, the superior paraolivary nucleus and the medial, lateral and ventral nuclei of the trapezoid body are described in C57BL/6 mice using Nissl, Bodian and Golgi techniques. Principal, spindle and marginal cells are present in a well-defined lateral superior olive. The dendrites of these cells run primarily within rostrocaudal sheets as in the cat. The principal cells of the medial nucleus of the trapezoid body are similar to the principal cells in the cat. Large multipolar cells characterize the lateral nucleus of the trapezoid body and bipolar cells with a medial-lateral orientation are found in the medial superior olive. The largest neurons are found in the superior paraolivary nucleus and the lateral superior olive, and the medial and ventral nuclei of the trapezoid body. While brain weight and neuronal packing density change with development, the characteristic location of cell groups and the shape and Nissl-staining pattern of neurons in the youngest brains examined were essentially unchanged in the adult mice, although dendritic maturation had occurred. The homologies of the C57BL/6 superior olivary complex nuclei with the same areas described in other mouse strains, rat and cat are discussed. This study expands our understanding of the organization of the superior olivary complex in an inbred strain of Mus musculus and relates it to other species. The data about changes occurring during postnatal maturation may aid in the interpretation of behavioral and physiological studies of neonatal plasticity of the auditory system.