Speech in noise listening correlates identified in resting state and DTI MRI images.

This study presents an examination of the neural connectivity associated with processing speech in noisy environments, an ability that declines with age. We correlated subjects' speech-in-noise (SIN) ability with resting-state MRI scans and Fractional Anisotropy (FA) values from the auditory section of the corpus callosum, both with and without correcting for age. The results revealed that subjects who performed poorly on the right ear SIN test (QuickSIN, MedRx) had higher correlations between the primary auditory cortex and regions of the brain that process language.

The Influence of Motoric Maneuvers on Cervical Vestibular Evoked Myogenic Potentials (cVEMPs).

Background: The cervical vestibular evoked myogenic potential (cVEMP) is a vestibular response that is produced by the saccule in response to intense, often low-frequency, short-duration auditory stimuli, and is typically recorded from a contracted sternocleidomastoid (SCM) muscle. Previous research has shown that the amplitude of the cVEMP is related to the amount of SCM electromyographic (EMG) activity.

Purpose: The aim of this study was to determine the influence of various remote motoric maneuvers on the amplitude of the cVEMP, as well as whether they influence the level of SCM EMG activity.

Initial testing of a 3D printed perfusion phantom using digital subtraction angiography.

Perfusion imaging is the most applied modality for the assessment of acute stroke. Parameters such as Cerebral Blood Flow (CBF), Cerebral Blood volume (CBV) and Mean Transit Time (MTT) are used to distinguish the tissue infarct core and ischemic penumbra. Due to lack of standardization these parameters vary significantly between vendors and software even when provided with the same data set.

Attenuated Tonic and Enhanced Phasic Release of Dopamine in Attention Deficit Hyperactivity Disorder.

It is unclear whether attention deficit hyperactive disorder (ADHD) is a hypodopaminergic or hyperdopaminergic condition. Different sets of data suggest either hyperactive or hypoactive dopamine system. Since indirect methods used in earlier studies have arrived at contradictory conclusions, we directly measured the tonic and phasic release of dopamine in ADHD volunteers.

Masked smoothing using separable kernels for CT perfusion images.

Background: CT perfusion images have a high contrast ratio between voxels representing different anatomy, such as tissue or vessels, which makes image segmentation of tissue and vascular regions relatively easy. However, grey and white matter tissue regions have relatively low values and can suffer from poor signal to noise ratios. While smoothing can improve the image quality of the tissue regions, the inclusion of much higher valued vascular voxels can skew the tissue values.

Attenuation of regional cerebral blood flow during memory processing after coronary artery bypass surgery.

Reports of memory impairment after cardiac surgery are controversial. To address this controversy, we used positron emission tomography to examine changes in regional cerebral blood flow (rCBF) during memory processing before and after elective coronary artery bypass grafting surgery. In postoperative scans, we observed significantly reduced rCBF in 2 of the most important memory processing areas: the medial temporal lobe (P = 0.

Masking level differences--a diffusion tensor imaging and functional MRI study.

In our previous study we investigated Masking Level Differences (MLD) using functional Magnetic Resonance Imaging (fMRI), but were unable to confirm neural correlations for the MLD within the auditory cortex and inferior colliculus. Here we have duplicated conditions from our previous study, but have included more participants and changed the study site to a new location with a newer scanner and presentation system. Additionally, Diffusion Tensor Imaging (DTI) is included to allow investigation of fiber tracts that may be involved with MLDs.

Improved operator agreement and efficiency using the minimum area contour change method for delineation of hyperintense multiple sclerosis lesions on FLAIR MRI.

Background: Activity of disease in patients with multiple sclerosis (MS) is monitored by detecting and delineating hyper-intense lesions on MRI scans. The Minimum Area Contour Change (MACC) algorithm has been created with two main goals: a) to improve inter-operator agreement on outlining regions of interest (ROIs) and b) to automatically propagate longitudinal ROIs from the baseline scan to a follow-up scan.

Methods: The MACC algorithm first identifies an outer bound for the solution path, forms a high number of iso-contour curves based on equally spaced contour values, and then selects the best contour value to outline the lesion.

Correlation of cognition and SPECT perfusion: easy Z score and SPM analysis of a pilot sample with cerebral small vessel disease.

Background/aims: To associate neuropsychology test performance with perfusion on single-photon emission computed tomography (SPECT) among 12 patients with cerebral small vessel disease.

Methods: The easy Z score imaging system (eZIS) was used to compare patient images to those of normal controls. Scores from neuropsychological tests commonly used to screen for dementia were associated with SPECT resting perfusion image values using the statistical parametric mapping (SPM) program.

Exercise treatment for postconcussion syndrome: a pilot study of changes in functional magnetic resonance imaging activation, physiology, and symptoms.

Purpose: To compare functional magnetic resonance imaging (fMRI) activation patterns during a cognitive task, exercise capacity, and symptoms in postconcussion syndrome (PCS) patients who received exercise treatment (n = 4) with a PCS placebo stretching group (n = 4) and a healthy control group (n = 4).

Methods: Subjects completed a math processing task during fMRI and an exercise treadmill test before (time 1) and after approximately 12 weeks (time 2). Exercise subjects performed aerobic exercise at 80% of the heart rate (HR) attained on the treadmill test, 20 minutes per day with an HR monitor at home, 6 days per week.

Functional anatomy of the masking level difference, an fMRI study.

Introduction: Masking level differences (MLDs) are differences in the hearing threshold for the detection of a signal presented in a noise background, where either the phase of the signal or noise is reversed between ears. We use N0/Nπ to denote noise presented in-phase/out-of-phase between ears and S0/Sπ to denote a 500 Hz sine wave signal as in/out-of-phase. Signal detection level for the noise/signal combinations N0Sπ and NπS0 is typically 10-20 dB better than for N0S0.

Improved assessment of multiple sclerosis lesion segmentation agreement via detection and outline error estimates.

Background: Presented is the method "Detection and Outline Error Estimates" (DOEE) for assessing rater agreement in the delineation of multiple sclerosis (MS) lesions. The DOEE method divides operator or rater assessment into two parts: 1) Detection Error (DE) -- rater agreement in detecting the same regions to mark, and 2) Outline Error (OE) -- agreement of the raters in outlining of the same lesion.

Methods: DE, OE and Similarity Index (SI) values were calculated for two raters tested on a set of 17 fluid-attenuated inversion-recovery (FLAIR) images of patients with MS.

Cine cerebrospinal fluid imaging in multiple sclerosis.

Purpose: To investigate cerebrospinal fluid (CSF) dynamics in the aqueduct of Sylvius in multiple sclerosis (MS) patients and healthy controls (HC) using cine phase contrast imaging.

Materials And Methods: In all, 67 MS patients (48 relapsing-remitting [RR] and 19 secondary-progressive [SP]), nine patients with clinically isolated syndrome (CIS), and 35 age- and sex-matched HC were examined. CSF flow and velocity measures were quantified using a semiautomated method and compared with clinical and magnetic resonance imaging (MRI) disease outcomes.

Evidence of dopaminergic processing of executive inhibition.

Inhibition of unwanted response is an important function of the executive system. Since the inhibitory system is impaired in patients with dysregulated dopamine system, we examined dopamine neurotransmission in the human brain during processing of a task of executive inhibition. The experiment used a recently developed dynamic molecular imaging technique to detect and map dopamine released during performance of a modified Eriksen's flanker task.

Neural correlates of tinnitus duration and distress: a positron emission tomography study.

Cerebral (18)F-deoxyglucose positron emission tomography (FDG-PET) has shown altered auditory pathway activity in tinnitus. However, the corresponding studies involved only small samples and analyses were restricted to the auditory cortex in most studies. Evidence is growing that also limbic, frontal, and parietal areas are involved in the pathophysiology of chronic tinnitus.

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.

A sensitive, noise-resistant method for identifying focal demyelination and remyelination in patients with multiple sclerosis via voxel-wise changes in magnetization transfer ratio.

Magnetization transfer imaging (MTI) provides a reliable and histopathologically validated means for identifying important tissue changes in multiple sclerosis (MS), including demyelination and remyelination. However, most approaches to date have been based on a priori regions of interest (ROIs) and have been relatively insensitive to small focal changes or competing processes. More recent techniques have sought to address this through a voxel-wise approach, but have been limited in their detection capabilities by the amount of noise in standard MTR images.

Signal abnormalities on 1.5 and 3 Tesla brain MRI in multiple sclerosis patients and healthy controls. A morphological and spatial quantitative comparison study.

Previous studies in patients with multiple sclerosis (MS) revealed increased lesion count and volume on 3 T compared to 1.5 T. Morphological and spatial lesion characteristics between 1.

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.

Resting brain glucose uptake in headache-free migraineurs.

Background And Objective: To compare metabolism in the brains of migraineurs during headache-free periods with those obtained from healthy volunteers.

Methods: Eleven migraineurs (defined by the International Headache Society's criteria) presented during spontaneous headache-free intervals to undergo (18)FDG PET brain imaging of glucose metabolism. The control group consisted of 14 healthy volunteers.

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.