Differences between mentally retarded and nonretarded persons' efficiency of auditory sentence processing

Mentally retarded adolescents and MA-matched nonretarded children participated in three experiments designed to examine differences in language-processing efficiency. A compressed speech technique was used in Experiments 1 and 2. Experiment 3 relied on a sentence-picture verification procedure. Our results suggest that retarded and nonretarded individuals differ in the speed with which they are able to execute the semantic-analytic processes but not necessarily the phonological encoding processes that are involved in auditory language comprehension. In addition, the data suggest a possible group difference in the quality of the semantic representation encoded during sentence processing.     

The effects of caffeine on various body systems: a review

Caffeine is the most widely consumed drug in Western society. The intake of caffeine-containing beverages in many adults and children often reaches levels that can induce pharmacological effects. Ninety-nine percent of ingested caffeine is absorbed and distributed to all tissues and organs. The effects of caffeine intake differ greatly according to acute or chronic intake, level of intake, and the development of tolerance. Caffeine administered acutely to non-users or recent abstainers can induce hypertension, arrhythmias, altered myocardial function, increased plasma catecholamine levels, plasma renin activity, serum cholesterol levels, increased production of urine, gastric acid secretion, and alterations in mood and sleep patterns. Tolerance to chronic caffeine intake develops in most individuals, with the cessation of its effects on the renal system, the cardiovascular system, the gastrointestinal system and, to some extent, the central nervous system. Moderate caffeine consumers probably need to have little concern for the effect of caffeine intake on their health if their other life-style habits are also moderate.     

Short and middle latency vestibular evoked responses to acceleration in man.

We have succeeded in recording short and middle latency vestibular evoked responses in human subjects. The head was held rigidly in a special, patented head holder, constructed individually for each subject, which gripped the teeth of the upper jaw. The stimulus consisted of 2/sec steps of angular acceleration impulses produced by a special motor with intensities of about 10,000 degrees/sec 2 and with a rise time of 1-2 msec. The electrical activity was recorded as the potential difference between special forehead and mastoid electrodes having a large, secure contact area with the skin. The activity was digitally filtered and averaged in 2 separate channels by means of a Microshev 2000 evoked response system. The short latency responses, with peaks at about 3.5 msec (forehead positive), 6.0 msec (forehead negative) and 8.4 msec (forehead positive; bandpass: 200-2000 Hz; average of 1024 trials), had amplitudes of about 0.5 microV. The middle latency responses had peaks at about 8.8 msec (forehead positive), 18.8 msec (forehead negative) and 26.8 msec (forehead positive; 30-300 Hz; N = 128 trials), with larger amplitudes (about 15 microV). These responses were consistently recorded in the same subject at different times and were similar in different normal subjects. Strenuous control experiments were conducted in order to ensure that these responses are not artefacts due to the movement of conducting media (head, electrodes and leads) in the electromagnetic field of the motor and are elicited by activation of normal labyrinths.(ABSTRACT TRUNCATED AT 250 WORDS)