Learning Effects and the Sensory Organization Test: Influence of a Unilateral Peripheral Vestibular Impairment.

Purpose: Healthy young controls exhibit a learning effect after undergoing repeated administrations of the sensory organization test (SOT). The primary objective of the present experiment was to determine if an SOT learning effect is present in individuals with a unilateral vestibular impairment (UVI), and if so, whether it is different from healthy controls. The secondary objective was to determine if the learning effect is dependent on the time frame of repeated SOT assessments.

The Influence of Caffeine on Rotary Chair and Oculomotor Testing.

Background: When patients are given instructions before vestibular function testing, they are often asked to refrain from ingesting caffeine 24 h before testing. However, research regarding the effects of caffeine on the outcome of vestibular function testing is limited.

Purpose: To evaluate whether the results from rotational chair tests are influenced by caffeine.

The influence of caffeine on the sensory organization test.

Background: Clinicians often request that patients refrain from consuming caffeinated beverages 24 h before vestibular function testing. However, there is limited research regarding how caffeine may affect the results of these tests. The sensory organization test (SOT) evaluates how well an individual is able to maintain his or her balance during several different conditions that manipulate vestibular, visual, or somatosensory information.

The influence of caffeine on calorics and cervical vestibular evoked myogenic potentials (cVEMPs).

Background: Prior to undergoing vestibular function testing, it is not uncommon for clinicians to request that patients abstain from caffeine 24 hr prior to the administration of the tests. However, there is little evidence that caffeine affects vestibular function.

Purpose: To evaluate whether the results from two tests commonly used in a clinical setting to assess vestibular function (i.

Use of 64-channel electroencephalography to study neural otolith-evoked responses.

Background: The vestibular evoked myogenic potential (VEMP) is a myogenic response that can be used clinically to evaluate the function of the saccule. However, to date, little is known about the thalamo-cortical representation of saccular activation. It is important to understand all aspects of the VEMP, as this test is currently used clinically in the evaluation of saccular function.

Multi-site phasic neural activity mediates the execution of an auditory continuous performance task: a PET and electrophysiological study.

Background And Purpose: We studied an auditory continuous performance task with positron emission tomography(PET) and EEG-derived current density reconstructions (CDRs) to define the spatial and temporal aspects of auditory attention.

Methods: The CDRs were employed to segregate responses to targets and non-targets at sites identified by PET. We then studied the time course of brain activity using statistical parametric mapping (SPM) of the CDR data.

Multi-site phasic neural activity mediates the execution of an auditory continuous performance task: a PET and electrophysiological study.

Background And Purpose: We studied an auditory continuous performance task with positron emission tomography (PET) and EEG-derived current density reconstructions (CDRs) to define the spatial and temporal aspects of auditory attention.

Methods: The CDRs were employed to segregate responses to targets and non-targets at sites identified by PET. We then studied the time course of brain activity using statistical parametric mapping (SPM) of the CDR data.

Cognitive therapy for irritable bowel syndrome is associated with reduced limbic activity, GI symptoms, and anxiety.

This study sought to identify brain regions that underlie symptom changes in severely affected IBS patients undergoing cognitive therapy (CT). Five healthy controls and 6 Rome II diagnosed IBS patients underwent psychological testing followed by rectal balloon distention while brain neural activity was measured with O-15 water positron emission tomography (PET) before and after a brief regimen of CT. Pre-treatment resting state scans, without distention, were compared to post-treatment scans using statistical parametric mapping (SPM).

Mapping the 40-Hz auditory steady-state response using current density reconstructions.

We mapped the 40-Hz aSSR from nine normal subjects using PET-independent low-resolution electroencephalographic tomography (LORETA) as well as PET-weighted LORETA and minimum norm (MinNorm) current density reconstructions. In grand mean data, PET-independent LORETA identified seven sites with peaks in current density in right temporal lobe, right brainstem/cerebellum, right parietal lobe, left cerebellum/temporal lobe, and right frontal lobe. PET-weighted LORETA found six of the same sites as the PET-independent LORETA: the right brainstem source was eliminated and two right-frontal sources were added.

PET imaging of the 40 Hz auditory steady state response.

The auditory steady state response (aSSR) is an oscillatory electrical potential recorded from the scalp induced by amplitude-modulated (AM) or click/tone burst stimuli. Its clinical utility has been limited by uncertainty regarding the specific areas of the brain involved in its generation. To identify the generators of the aSSR, 15O-water PET imaging was used to locate the regions of the brain activated by a steady 1 kHz pure tone, the same tone amplitude modulated (AM) at 40 Hz and the specific regions of the brain responsive to the AM component of the stimulus relative to the continuous tone.

Functional imaging during covert auditory attention in multiple sclerosis.

Recent literature suggests that the brain in multiple sclerosis (MS) undergoes reorganization that subserves the performance of visual and motor tasks. We identified sites of cerebral activity in 16 MS patients while performing a covert attention (CA) task, presented in the auditory modality. Positron emission tomography (PET) revealed activation of rostral/dorsal anterior cingulate cortex (ACC) in normal subjects studied previously.

Mapping the neural systems that mediate the Paced Auditory Serial Addition Task (PASAT).

The paced auditory serial addition task (PASAT), in which subjects hear a number-string and add the two most-recently heard numbers, is a neuropsychological test sensitive to cerebral dysfunction. We mapped the brain regions activated by the PASAT using positron emission tomography (PET) and 15O-water to measure cerebral blood flow. We parsed the PASAT by mapping sites activated by immediate repetition of numbers and by repetition of the prior number after the presentation of the next number in the series.

Development of a longitudinal study of complications and functional outcomes after traumatic brain injury.

Primary Objective: To create a longitudinal database of patients with moderate and severe traumatic brain injury.

Research Design: A prospective study design was used to collect data pertaining to demographics, acute and post-acute management, complications, resource utilization and functional outcomes.

Methods And Procedures: Data were collected on 233 patients with a Glasgow Coma Score of 12 or less, admitted to a Level 1 Trauma Centre within 24 hours of injury and continued through post-hospitalization follow-up.

Brain imaging of the effects of lidocaine on tinnitus.

Using a single-blind placebo-controlled design, we mapped lidocaine related changes in neural activity, measured by regional cerebral blood flow (rCBF) with (15)O-H(2)O positron emission tomography. Intravenous lidocaine produced both increases and decreases in the loudness of tinnitus. The change in tinnitus loudness was associated with a statistically significant change in neural activity in the right temporal lobe in auditory association cortex.

Covert auditory attention generates activation in the rostral/dorsal anterior cingulate cortex.

The anterior cingulate cortex (ACC) is believed to mediate conscious information processing or high-capacity attention. However, previous functional imaging studies have largely relied on tasks that involve motor function as well as attention. The work from our group utilizing an auditory continuous performance task demonstrated increased activity in a caudal division of the ACC that borders the supplementary motor area (SMA).