Early static pressure-related evoked brain potentials indications of central middle ear pressure control in humans.

Hypothesis: The aim of this study was to investigate the possibility of afferent subcortical components related to static pressure changes of the human middle ear.

Background: The normal middle ear function depends on a proper regulation of middle ear pressure, whereas an inadequate regulation with negative pressures is considered a major pathogenetic factor responsible for a variety of middle ear disorders. However, although studies on middle ear pressure and related clinical problems are common, studies on the role of its central control have been remarkably few.

Is the pain in chronic pancreatitis of neuropathic origin? Support from EEG studies during experimental pain.

Aim: To prove the hypothesis that patients with chronic pancreatitis would show increased theta activity during painful visceral stimulation.

Methods: Eight patients and 12 healthy controls underwent an experiment where the esophagus was electrically stimulated at the pain threshold using a nasal endoscope. The electroencephalogram (EEG) was recorded from 64 surface electrodes and "topographic matching pursuit" was used to extract the EEG information in the early brain activation after stimulation.

Pain in chronic pancreatitis: the role of reorganization in the central nervous system.

Background & Aims: In various chronic pain conditions cortical reorganization seems to play a role in the manifestations. The aim of this study was to investigate cortical reorganization in patients with pain caused by chronic pancreatitis.

Methods: Twelve healthy subjects and 10 patients with chronic pancreatitis were included.

The "human visceral homunculus" to pain evoked in the oesophagus, stomach, duodenum and sigmoid colon.

The oesophagus, stomach, duodenum and sigmoid colon were electrically stimulated in 12 healthy volunteers with a thin nasal endoscope. The painful cortical evoked potentials (EPs) were recorded from 64 surface electrodes. The early EPs with latencies < 200 ms were studied and the corresponding dipole sources were calculated.