Faculty Bibliography

Pain responses (pain detection and pain discomfort) to electrical dental stimulation were studied in 16 normal subjects. The repetition of the dental stimuli induced a significant and long-lasting (60 min) decrease in pain sensitivity at both sensory levels (after 60 min of repetitive stimulation, 79% increase in pain detection, P less than 0.0001, 45% increase in pain discomfort, P less than 0.0004). The sensory response decrement through repeated elicitation was not influenced by naloxone administration (1.2 mg i.m.). This study clearly demonstrates the induction of pain sensory decrease through repetitive stimulation which differs from peripheral sensory receptor adaptation, from the inhibitory gating mechanism or from diffuse inhibitory controls activation; its unresponsiveness to naloxone suggests that this phenomenon is not opioid-dependent. A technique has been standardized which will enable the systematic study of pain decrease under sustained nociceptive stimulation in chronic pain patients

Three subjects, presenting a variety of chronic pain problems, were treated with a cross-modality feedback technique. Their presenting pain intensity was matched to a pure tone auditory stimulus decibel level and in each session this stimulus was progressively reduced in loudness, with the subjects having the task of reducing their pain to match each new, lower decibel levels. Audiometric measures, responses to pain assessment scales, self-reports, reports from hospital staff, and reductions in pain medications all demonstrated marked pain reduction in all cases. Follow-up assessments revealed that the improvements were maintained long after treatment had been discontinued

Two cases are reported in which subjective tinnitus aurium was treated with a matching-to-sample procedure. Following baseline evaluations, the subjects' experienced tinnitus was reproduced audiometrically in terms of loudness, frequency, and quality. This was presented to them in the noninvolved ear and was gradually reduced within sessions. The subjects were required to concentrate on reducing their tinnitus until an equal match had been achieved between it and the stimulus sound at each new decibel level. Both subjects gained control over their tinnitus and were able to reduce it markedly from baseline levels. This procedure is viewed as an advance over other techniques not only in that it significantly reduces the tinnitus but in the fact that it is done through the subject's own control, providing psychological benefit as well

A 96-trial tachistoscope recognition task was given to 15 left-hemisphere-damaged, 12 right-hemisphere-damaged, and 30 non-brain-damaged subjects. Procedure called for a first stimulus presented for 250 msec, a 1-sec. pause, and a second stimulus for 250 msec. The stimuli were 12 animal drawings used in repeated series according to a random schedule. Six animals were familiar and six were novel. For half of the trials, the two pictures were of different animals. Size and position of the animal picture were controlled. Both reaction time and accuracy were independently scored. Judgments of same and different appear to function as if they are governed by different processes. For the control group, measures of same and different judgments do not correlate highly despite high internal consistency of subtests. Recognition of same becomes impaired with brain damage, but more so if the damage is rightsided. Recognition of different judgments shows considerably less sensitivity to the effects of unilateral brain damage