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Prolonged Latencies (prolonged + latency)

Distribution by Scientific Domains

Medical Sciences	100%

Selected Abstracts

Mal de Debarquement and Posture: Reduced Reliance on Vestibular and Visual Cues

THE LARYNGOSCOPE, Issue 3 2004
Zohar Nachum MD
Abstract Objective The neural mismatch theory assumes that the intersensory conflicts leading to motion sickness are resolved by changes in the relative weighting of the various senses that contribute to orientation. If this sensory rearrangement persists after disembarkment, it might result in mal de debarquement (MD): ataxia and a rocking sensation sometimes felt after landing. The objective of the present study was to examine possible changes in sensory organization in naval crew members with differing susceptibility to MD with computerized dynamic posturography (CDP). Study Design Cross-sectional parallel-group design. Methods Seventeen subjects susceptible to MD (SMD) and 17 subjects nonsusceptible to MD (NSMD) (healthy male volunteers aged 18,22) participated in the study. CDP was performed twice with each subject, before and immediately after sailing, using the EquiTest system (NeuroCom, Inc., Clackamas, OR). Results The SMD group showed a significant reduction in their scores on sensory organization tests 3, 4, and 5 after sailing. Sensory pattern analysis revealed reduced use of inputs from the vestibular and visual systems to maintain balance. Prolonged latencies of the motor responses to unexpected pitch perturbations were also recorded in the postsailing CDP of the SMD group. Reduced performance on the presailing CDP task, which presents the greatest challenge to the vestibular system, was found to control for the presence of MD postsailing. Conclusions The results show that MD is associated with postural instability, slower motor reflexes, and larger sways in response to abrupt changes in the body's center of gravity. These findings may be explained by under reliance on vestibular and visual inputs and increased dependence on the somatosensory system for the maintenance of balance. [source]

Effects of the antiepileptic drugs on peripheral nerve function

ACTA NEUROLOGICA SCANDINAVICA, Issue 1 2010
E. Boylu
Objective,,, We aimed to compare the effects of antiepileptic drugs and provide findings of peripheral nerve impairment using standard electrophysiological techniques. Materials and methods,,, Young adult outpatients with epilepsy on monotherapy for no less than 6 months with carbamazepine (CBZ), valproic acid (VPA), oxcarbazepine (OXC) and topiramate (TPM) were examined. Patients who had any other disease that could effect nerve conduction studies and who had neuropathic symptoms were excluded. Results,,, Each group contained 15 patients and 20 healthy subjects were examined as the control group. Prolonged latency of median sensory nerve (P = 0.004), ulnar sensory nerve (P = 0.01) and sural nerve (P = 0.003) with a diminished nerve conduction velocity was observed in the CBZ group (P = 0.014, P = 0.002, P = 0.025, respectively). No correlation was found between VPA, OXC and TPM and the nerve conduction studies (P > 0.05). Conclusions,,, Valproic acid, oxcarbazepine and topiramate don't have effects on nerve conduction studies. Mild electrophysiological changes contribute to carbamazepine therapy. [source]

A review of EEG and ERP studies in bipolar disorder

ACTA NEUROPSYCHIATRICA, Issue 2 2009
Racheal Degabriele
Objective:, The electroencephalogram (EEG) can be a useful tool in determining differences in general neural activity and specific waveforms in individuals with a number of psychiatric disorders. This paper aims to outline and discuss significant findings in EEG and event-related potential (ERP) research into bipolar disorder (BD). Methods:, A literature review was performed through searches of MedLine, EMBASE, CINAHL and PsycInfo medical research databases for papers published from 1985 onwards. References of selected articles were also examined for other relevant studies. Results:, Differences in general EEG data were found in subjects with BD, namely increased theta and delta and decreased alpha wave bands. Changes in EEG were also found in euthymic BD subjects and those undergoing medication programmes. ERP studies commonly report prolonged latencies and reduced amplitudes in the P300 component. Hyperfunctioning of the right hemisphere in BD was also reported in some studies, although further confirmation of this finding is required. Finally, the effects of medication and the role that genetics plays in EEG still remain unclear. Conclusions:, The literature reviewed demonstrates supporting evidence for the presence of significant differences in EEG and ERP data in subjects with BD. However, methodological considerations such as varying mood states and medication status of the patients need to be followed more stringently for future research to bring about a robust model of the cognitive deficits of BD. [source]

Function of macular area in retinopathy of prematurity

ACTA OPHTHALMOLOGICA, Issue 2007
AM SHAMSHINOVA
Purpose: To assess the bioelectric activity of the retina at different stages of the retinopathy of prematurity (RP). Methods: 21 children with RoP (stage 1-4, 6-14 years old, born at 27-32 week of gestation with the birth weight of 730-1800g) were examined. In 4 of children the prophylactic laser coagulation of avascular retina was performed in the active phase. Visual acuity (VA) at the stage 1 of RoP amounted to 0,75; at the stage 2: 0,5; at the stage 3: 0,25 and at the stage 4: 0,02. Macular (MBN Moscow) and mf ERG( Roland Concult Germany) were examined. Results: There was no correlation between VA values and parameters of multifocal (mf) and macular (m) ERG. Patients with RP of stage1 showed a moderate reduction of b-wave magnitude of mERG at its normal latency. This correlated with mfERG data in central hexagons 15 degrees. The magnitude and latency of mERG were changed to a great extent in RP patients of stages 2-3. The waves N1 and P1 of mERG were also heavily decreased at normal latency. The patients with severe retinal abnormalities, like retinal detachment, have subnormal mERG-values with prolonged latency, and moderate decrease of retinal density in the central ring and considerable changes with eccentricity in mfERG. Conclusions: RP patients 1-4 stages showed considerable impairment of macular function independent of the ophthalmoscopic changes. Even occult or weak-manifested of the diseases in the macula might be accompanied with the moderate decrease of macular bioelectric activity, including the abrupt abnormalities of the electrogenesis and neuronal interactions in the macular area. Decline VA d'not always had relation with RP. The pathophysiologic rationale of the latter needs to be elucidated in the future studies. [source]