Bodily misperceptions are a frequent symptom in major depressive disorder. A reduced ability to deflect attention from somatosensory stimuli may contribute to the generation of unpleasant bodily sensations and co-occur with altered habituation of the brain electric reactions to somatosensory stimuli. The aim of the present study was to explore whether attention-related components of somatosensory evoked potentials (SSEP) and the habituation of these components are altered in major depression. Fifteen patients with major depressive disorder were compared to an age- and gender-matched group of 15 healthy controls. A series of identical, intrusive but not painful electric stimuli were applied to the left index finger for 48 min. Averaged SSEP were computed from multichannel EEG recordings for consecutive recording blocks of the experiment, each block containing 162 stimuli. Based on these data the habituation process of late components of the SSEP was analysed in two latency intervals (50-150, 170-370 ms). Patients showed significantly enhanced reactions throughout the entire experiment. The persistence of enhanced SSEP components throughout the habituation process may be caused by a deficit in reducing the activity of attention-related brain processes concerned with intrusive, yet behaviourally irrelevant, continued stimulation in the state of major depression.

Adult↗

PubMedDate not supplied

Pain perception in patients with eating disorders.

The heat pain threshold was measured with phasic and tonic stimuli under basal conditions and after naloxone administration in 10 anorectic and 10 bulimic patients as well as in 11 healthy control subjects. Under both kinds of stimulation, the basal threshold values were elevated in the bulimic patients and in some of the anorectic patients. Naloxone did not differ from placebo in its effect on the pain thresholds (phasic and tonic), suggesting that a nonopioid mechanism was responsible for the threshold elevation found in the eating disorder patients. The plasma cortisol concentration was similar in the three groups and not correlated with the basal pain thresholds in the patients. Other indicators of dieting such as beta-hydroxybutric acid and triiodothyronine also showed no correlation with the basal pain thresholds. Significant height correlations can be interpreted as weak evidence that neuropathy is the cause of the increase in the pain threshold.

Adult↗

PubMedDate not supplied

Similarities in age differences in heat pain perception and thermal sensitivity.

Age differences in the thresholds for heat pain, warmth and cold were studied in 64 healthy persons from 17 to 63 years of age (32 women, 32 men). The stimuli were applied to the thenar and the dorsum pedis with a contact thermode. The thresholds increased significantly with age in all modalities on the foot, but not on the hand. Furthermore, the quotients of the individual foot and hand thresholds revealed a significant relative increase in all thresholds on the foot. The length of the afferent pathways seems to influence the degree of age-related changes both in heat pain perception and in thermal sensitivity, resulting in a distal-proximal pattern of age-dependent decline.

Adolescent↗