A note on the failure to find personality differences between volunteers and nonvolunteers for hypnotic research

Personality measures were administered to 136 students in an introductory psychology class at Brigham Young University. 30 Ss sudsequently volunteered to have their hypnotic susceptibility assessed. There were no significant differences found between the means of the resulting 23 variables for the 30 volunteers and 106 nonvolunteers. Two variables (age and ego strength) showed significantly different variances for the two groups, but these may be attributed to chance because of the number of significance tests made.     

Social and environmental perceptions of susceptible and unsusceptible hypnotic subjects

In this investigation the hypothesis waa tested that in hypnosis Ss would provide richer protocols in the House-Tree Person projective technique than in the waking state. Impressionistic analysis tended to support thia view. It was further hypothesized that difierent subteat and total Scores would be yielded in the two states on the Minnesota Personslity Scale. Quantitative findings were statistically insignificant.     

Evoked potentials and selective attention in subjects capable of hypnotic analgesia

Somatosensory and auditory evoked responses were recorded in 3 hypnotic Ss who had previously undergone surgical procedure without chemical anesthesia, and in 2 who were able to control organic pain. The Ss were studied in an attention experiment carried out in non-hypnotic and hypnotic states, as defined by their subjective criteria. They were required to press a key to either a click or shock stimulus, presented in random order, during each averaging sequence. In the non-hypnotic state, increased amplitudes of the late wave response were obtained; during the hypnotic state, responding to either clicks or shocks failed to produce changes in the amplitudes of these responses. In addition, hypnotically induced changes in click or shock perception failed to be accompanied by corresponding changes in evoked response amplitude. These findings were interpreted as indicating incressed stability of arousal and evoked response during the hypnotic state.     

A note on shock tolerances of real and simulating hypnotic subjects

Prior to the induction of hypnosis, Ss who later in an experiment were actually to be hypnotized selected lower criterion electric shock levels than did Ss who later were only to simulate hypnosis. This is the first quantified objective difference found to date between the behavior of Reals and Simulators.     

Motor imagery during hypnotic arm paralysis in high and low hypnotizable subjects.

Previous research suggests that conversion disordered patients with hand/arm paralysis exhibit slowed reaction times for mental hand-rotation tasks that correspond to their affected arm when the tasks are explicitly instructed and not when they are implicitly cued. Because of the many similarities between hypnotic phenomena and conversion symptoms, the authors tested whether similar motor imagery impairment would occur among normal high hypnotizable subjects when paralysis is suggested. Nine high and 8 low hypnotizable subjects were administered an implicit and an explicit mental hand-rotation task during hypnotically suggested paralysis of the right arm. On the implicit task, there were no significant reaction time (RT) differences between highs and lows. On the explicit task, only highs showed a significantly larger RT increase per degree of rotation with the paralyzed arm, compared to the normal arm. These preliminary findings suggest that the motor imagery impairment observed in conversion paralysis can be induced in highs using hypnosis.     

Pharmacokinetics of cefoperazone in normal volunteers and subjects with renal insufficiency

We examined the pharmacokinetics of the new beta-lactam agent, cefoperazone, in normal and functionally anephric dialysis subjects with normal liver function. All subjects received 3 g of cefoperazone intravenously, and serial serum and urine samples were taken thereafter for up to 36 h. The serum levels, volume of distribution (0.22 liter/kg, normal; 0.19 liter/kg; dialysis), beta half-life (2.07 h, normal; 2.03 h, dialysis), and total body clearance (96.2 ml/min, normal; 92.9 ml/ min, dialysis) were all not significantly different between the two groups. Cefoperazone may be administered without adjustment of dose for any degree of renal dysfunction to patients with normal hepatic function.     

Subject posture and hypnotic susceptibility: A comparison of standing,sitting, and lyingdown subjects

Because of the prominence of relaxation instructions and suggestions of sleep within common hypnotic induction procedures, it seemed a reasonable conjecture that, in comparison to the customary sitting posture, a lying-down posture would facilitate hypnosis and a standing posture inhibit it. A preliminary experiment, using a slightly modified, tape-recorded Stanford Hypnotic Susceptibility Scale, Form C, failed to support either hypothesis. A subsequent experiment under improved conditions with 20 Ss in each group (standing, sitting, and lying down) also showed no significant difference of mean hypnotic susceptibility scores between any 2 of the conditions.

Although Ss expressed dislike for the standing posture, the only objective disadvantage seemed to be some dizziness or nausea generated for some Ss (5 out of 39 tested in the standing condition). No clear evidence exists that this effect is to be attributed to hypnosis rather than to standing with eyes closed for an appreciable time.

The results show that hypnotic behavior may be little affected by the concomitant requirements of maintaining a standing or sitting posture, even with the use of an induction which emphasizes relaxation.     

Myocardial T2 mapping reveals age- and sex-related differences in volunteers

Background

T2 mapping indicates to be a sensitive method for detection of tissue oedema hidden beyond the detection limits of T2-weighted Cardiovascular Magnetic Resonance (CMR). However, due to variability of baseline T2 values in volunteers, reference values need to be defined. Therefore, the aim of the study was to investigate the effects of age and sex on quantitative T2 mapping with a turbo gradient-spin-echo (GRASE) sequence at 1.5 T. For that reason, we studied sensitivity issues as well as technical and biological effects on GRASE-derived myocardial T2 maps. Furthermore, intra- and interobserver variability were calculated using data from a large volunteer group.

Methods

GRASE-derived multiecho images were analysed using dedicated software. After sequence optimization, validation and sensitivity measurements were performed in muscle phantoms ex vivo and in vivo. The optimized parameters were used to analyse CMR images of 74 volunteers of mixed sex and a wide range of age with typical prevalence of hypertension and diabetes. Myocardial T2 values were analysed globally and according to the 17 segment model. Strain-encoded (SENC) imaging was additionally performed to investigate possible effects of myocardial strain on global or segmental T2 values.

Results

Ex vivo studies in muscle phantoms showed, that GRASE-derived T2 values were comparable to those acquired by a standard multiecho spinecho sequence but faster by a factor of 6. Besides that, T2 values reflected tissue water content. The in vivo measurements in volunteers revealed intra- and interobserver correlations with R²=0.91 and R²=0.94 as well as a coefficients of variation of 2.4% and 2.2%, respectively. While global T2 time significantly decreased towards the heart basis, female volunteers had significant higher T2 time irrespective of myocardial region. We found no correlation of segmental T2 values with maximal systolic, diastolic strain or heart rate. Interestingly, volunteers´ age was significantly correlated to T2 time while that was not the case for other coincident cardiovascular risk factors.

Conclusion

GRASE-derived T2 maps are highly reproducible. However, female sex and aging with typical prevalence of hypertension and diabetes were accompanied by increased myocardial T2 values. Thus, sex and age must be considered as influence factors when using GRASE in a diagnostic manner.

Electronic supplementary material

The online version of this article (doi:10.1186/s12968-015-0118-0) contains supplementary material, which is available to authorized users.     

Pattern of hippocampal shape and volume differences in blind subjects

Numerous studies in animals and humans have shown that the hippocampus (HP) is involved in spatial navigation and memory. Blind subjects, in particular, must memorize extensive information to compensate for their lack of immediate updating of spatial information. Increased demands on spatial cognition and memory may be associated with functional and structural HP plasticity.Here we examined local size and shape differences in the HP of blind and sighted individuals. A 3D parametric mesh surface was generated to represent right and left HPs in each individual, based on manual segmentations of 3D volumetric T1-weighted MR images of 22 blind subjects and 28 matched controls. Using a new surface mapping algorithm described in (Shi, Y., Thompson, P.M., de Zubicaray, G.I., Rose, S.E., Tu, Z., Dinov, I., Toga, A.W., Direct mapping of hippocampal surfaces with intrinsic shape context, NeuroImage, Available online May 24, (In Press).), we created an average hippocampal surface for the controls, and computed its normal distance to each individual surface. Statistical maps were created to visualize systematic anatomical differences between groups, and randomization tests were performed to correct for multiple comparisons.In both scaled and unscaled data, the anterior right HP was significantly larger, and the posterior right HP significantly smaller in blind individuals. No significant differences were found for left HP. These differences may reflect adaptive responses to sensory deprivation, and/or increased functional demands on memory systems. They offer a neuroanatomical substrate for future correlations with measures of navigation performance or functional activations related to variations in cognitive strategies.     

Electromyographic investigation of hypnotic arm levitation: differences between voluntary arm elevation and involuntary arm levitation

Thirty-three volunteers were randomly exposed to 3 conditions: hypnotic arm levitation, holding up the arm voluntarily without hypnosis, and imagined arm lifting without hypnosis. Trapezius, deltoid, extensor digitorum, flexor digitorum profundus, biceps brachii, and triceps brachii muscles were measured. Strain and muscle activity during lifting and holding up the right arm for 3 minutes were used as dependent variables. During hypnotic arm levitation, the total muscle activity was lower than during holding it up voluntarily (p < .01); the activity in the deltoid was 27% lower (p < .001). Without hypnosis, the muscle activity showed a positive correlation with strain. However, there was no such correlation in the hypnotic condition. Apparently, it is possible to reduce strain and to objectively measure muscle activity in an uplifted arm through hypnotic arm levitation.     

Effects of an opioid antagonist on pain intensity and withdrawal reflexes during induction of hypnotic analgesia in high- and low-hypnotizable volunteers

The aim of this investigation was to study the effect of suggestions of hypnotic analgesia on spinal pain transmission and processing. Pain intensity and amplitude of nociceptive withdrawal reflexes to electrical stimuli were measured in 10 high- and 10 low-hypnotizable subjects during two sessions taking place at least 24 h apart under five conditions of. (1) pre-hypnosis; (2) neutral hypnotic relaxation; (3) suggestions of hypnotic analgesia; (4) suggestions of hypnotic analgesia after injections of either naloxone (1 ml, 1 mg/ml) or saline (1 ml) under double-blinded conditions; and (5) post-hypnosis. The conditions of naloxone or saline were allocated at random to either Day 1 or Day 2 in a double-blinded fashion. Results showed significant reductions of pain intensity during hypnotic analgesia, and a significant reduction in nociceptive reflexes during hypnotic analgesia on Day 1 in the highly hypnotizable group. No differences were found for low-hypnotizable subjects. The results support previous findings that pain intensity as well as the nociceptive reflex can be modulated by suggestions of hypnotic analgesia. While no effect of naloxone on pain intensity was found during hypnotic analgesia, naloxone significantly reversed the suppressive effect of suggestions of hypnotic analgesia on reflexes in high-hypnotizable subjects. Subsequent analysis showed that the effect of naloxone was associated with the intensity of the stimulus needed to elicit a reflex, and was unrelated to hypnotic susceptibility when controlling for stimulus intensity. These results suggest that the effect of naloxone was related to the greater stimulus intensities needed to elicit a reflex in the high-hypnotizable group, rather than to hypnosis or hypnotic susceptibility in itself. It is unclear why greater stimulus intensities were needed in high-hypnotizable subjects and further studies are needed.     

Cefmenoxime pharmacokinetics in healthy volunteers and subjects with renal insufficiency and on hemodialysis.

The pharmacokinetics of cefmenoxime were characterized in five healthy volunteers and in 15 subjects with various degrees of renal insufficiency after a single 10-mg/kg, 5-min intravenous infusion. Five of these subjects were studied both on hemodialysis and during an interdialytic period. Plasma, urine and dialysate were assayed for cefmenoxime by a specific high-pressure liquid chromatographic assay. Peak plasma concentrations of cefmenoxime were ca. 94 micrograms/ml after completion of the infusion. The mean plasma and renal clearances in the healthy volunteers were 281 +/- 66 and 228 +/- 52 ml/min, respectively. Plasma clearance declined in patients with renal insufficiency and correlated significantly with creatine clearance. The mean apparent volume of distribution at steady state in the healthy volunteers was 0.23 liters/kg and was not found to be significantly different in subjects with renal insufficiency. The mean cumulative 24-h urinary recovery of cefmenoxime in healthy volunteers was 81% of the administered dose and decreased with reduced renal function. Cefmenoxine dosage should be reduced in proportion to the decline in creatinine clearance. A simple nomogram for dose selection is provided.