Neurophysiological correlates of post-hypnotic alexia: a controlled study with Stroop test.

To clarify whether hypnotically-induced alexia was able to reduce the Stroop effect due to color/word interference, 12 volunteers (6 with high and 6 with low hypnotizability according to Stanford Hypnotic Susceptibility Scale Form C) underwent a Stroop test consisting of measuring, both in basal conditions and during post-hypnotic alexia, the reaction times (RT) at appearance of a colored word indicating a color. In basal conditions, RT were greater in case of incongruence. In highly hypnotizable participants, the interference was less pronounced during post-hypnotic alexia (-34%, p = 0.03). During alexia, late positive complexamplitude was also greater for congruent than incongruent conditions (p < 0.03), and cardiovascular response to stress was less pronounced as well. In participants showing low hypnotizability, no reduction of Stroop effect was detected during post-hypnotic alexia. Posthypnotic alexia is therefore a real and measurable phenomenon, capable of reducing the color-word interference and the haemodynamic effects of the Stroop test.

Electrocardiographic criteria of left ventricular hypertrophy in general population.

The question on whether the electrocardiographic criteria are reliable for detection of left ventricular hypertrophy (LVH) and play a role in predicting outcome is open. Answer can only proceed from population-based studies over unselected people followed up for years. In this study, 1,699 subjects from general population underwent echocardiogram and standard electrocardiogram (ECG) codified for LVH with Minnesota code and with other five methods. Other items were also recorded and used as covariables. Left ventricular mass index (LVMI) was 127.6 +/- 44.9 g m(-2) in men and 120.8 +/- 41.2 g m(-2 )in women, and correlated directly with age in both genders. Prevalence of echocardiographic LVH was 36.6% in men and 53.4% in women. LVMI correlated directly with the Sokolow-Lyon score in both genders at any age, with the Romhilt-Estes, Cornell and R(aVL) scores in all subjects but elderly men, and with the Lewis score in men and women aged < or =69 years. Sensitivity and the predictive value of electrocardiographic tests, as well as the prevalence of LVH diagnosed with electrocardiographic criteria, were always low. Specificity was high for all the tests, and in particular for the Cornell index. Only when diagnosed with echocardiogram or with the Sokolow-Lyon criterion, LVH was an independent predictor of mortality. We conclude that electrocardiographic tests cannot be used as a surrogate of echocardiogram in detecting LVH in the general population because their positive predictive value (PPV) is unacceptably low. On the contrary, they could replace echocardiography in the follow up and for prediction of outcome, when LVH has previously been correctly diagnosed with other methods.

Hypnosis prevents the cardiovascular response to cold pressor test.

To highlight the effects of hypnotic focused analgesia (HFA), 20 healthy participants underwent a cold pressor test (CPT) in waking basal conditions (WBC) by keeping the right hand in icy water until tolerable (pain tolerance); subjective pain was quantified by visual scale immediately before extracting the hand from water. The test was then repeated while the participants were under hypnosis and underwent HFA suggestions. Cardiovascular parameters were continuously monitored. Pain tolerance was 121.5+/-96.1 sec in WBC and 411.0+/-186.7 sec during HFA (p < 0.0001), and visual rating score 7.75+/-2.29 and 2.45+/-2.98 (p < 0.0001), respectively. CPT-induced increase of total peripheral resistance was non significant during HFA and +21% (p < 0.01) in WBC. HFA therefore reduced both perception and the reflex cardiovascular consequences of pain as well. This indicates that hypnotic analgesia implies a decrease of sensitivity and/or a block of transmission of painful stimuli, with depression of the nervous reflex arc.