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Wave Latencies (wave + latency)
Selected AbstractsELECTRONEUROGRAPHY IN GUILLAIN-BARRE, SYNDROME (GBS): SENSITIVITY AND SPECIFICITYJOURNAL OF THE PERIPHERAL NERVOUS SYSTEM, Issue 1 2000G. Iuliano We assessed clinical sensitivity and specificity of different electroneurographic (ENG) parameters versus clinical diagnosis of GBS. Clinical data of 24 patients affected by upper and lower limb neuropathy were revised. In all the patients the neurophysiologic examination was performed according to the AAEM guidelines for GBS diagnosis. Fourteen patients (10 males, mean age 47.9, range 13-70, and 4 females 71.5, 69,76) received a diagnosis of GBS. The non-GBS group included nine males (59.11, 35,78) and one female (41 years) with different neuropathies (3 diabetic, 2 alcoholic, 5 unknown ethiology). Sensitivity and specificity of various neurophysiologic parameters were calculated. The single classical neurophysiological paremeters gave variable values of sensitivity and specificity. The new variables we introduced, Polineuropathy (diffusion of abnormal findings and F - Wave latency) and Demyelination (distal motor evoked potential amplitude and/or motor conduction blocks) gave the highest value of sensitivity and specificity, when associated. [source] CLINICAL AND IMMUNOLOGICAL FEATURES AND RESPONSE TO IVIg IN PATIENTS WITH CLINICALLY TYPICAL MULTIFOCAL MOTOR NEUROPATHY BUT NO OVERT CONDUCTION BLOCKJOURNAL OF THE PERIPHERAL NERVOUS SYSTEM, Issue 1 2000E. Nobile-Orazio Multifocal motor neuropathy (MMN) is characterized by progressive asymmetric limb weakness usually predominant in the upper limbs associated with conduction block (CB) in motor but not sensory nerves. There are, however, occasional patients with clinically typical MMN in whom no CB can be detected. Whether these patients differ from patients with MMN and CB remains unclear. Since 1991, we have observed 24 patients with the typical clinical features of MMN. In 20 of them (14 men and 6 women), electrophysiological studies disclosed the presence of CB in at least one motor nerve. In four (all women), no evidence of CB could be detected in examined nerves even if three had some features of demyelination, including asymmetric reduction of motor conduction velocities (1 patient) or prolonged or absent F wave latencies (3 patients). Three of them had markedly reduced or absent proximal and distal CMAP amplitudes in some nerves. The mean age of onset of MMN was similar in patients with (41.5 years, range 21,70) and without CB (41.5 years, range 24,57). The mean duration of the disease at the time of our first visit was longer in patients without CB (18.5 years, range 13,25) than in those with CB (6.3 years, 3 months,25 years); only 3 patients with CB had a duration of the disease longer than 10 years. All patients without CB had a predominant or exclusive impairment of upper limbs compared with 18 (90%) of those with CB. The mean Rankin score before therapy was slightly worse in patients without (2.5) than with (2.2) CB. Anti-ganglioside antibodies were found in 1 patient without CB (25%) and in 8 (40%) with CB. All but 2 patients with CB (90%) consistently improved with IVIg. All patients without CB also improved with IVIg, but only one did so consistently. In conclusion, patients with the typical clinical presentation of MMN but no overt CB are clinically and immunologically indistinguishable from those with MMN and CB. The longer duration of the disease and frequent axonal impairment in patients without CB may explain the lower efficacy of IVIg in these patients than in those with CB. [source] Effect of intravitreal injection of indocyanine green, triamcinolone acetonide and trypan blue on the electroretinographic response in the ratACTA OPHTHALMOLOGICA, Issue 2007C GARCHER CREUZOT Purpose: The purpose of this study was to evaluate the effects of intravitreal injection of ICG (indocyanine green), TB (trypan blue) and TA (triamcinolone acetonide) on the visual function assessed by electroretinogram (ERG) in the rat. Methods: Three groups of 12-week-old Sprague Dawley rats (n=6) received intravitreal injection in one eye of 0.1mL of either ICG 0.5mg/mL, TB 3mg/mL or TA 40mg/mL followed by a rinse with 1mL of saline solution. The controlateral eye was used as a control and was injected similarly with saline only. The scotopic ERG was recorded at different intensities (10mcds/mē, 2500mcds/mē and 25000mcds/mē) before injection and 28 days after treatment. Results: No effect of the treatment was observed on the ERG amplitudes and wave latencies in control eyes and in eyes treated with TB and TA. The ERG b-wave amplitudes and latencies were significantly reduced in eyes treated with ICG at 10mcds/mē and 2500mcds/mē but not at 25000mcds/mē (amplitude means: t0=174.8,V versus t28=55.0,V at 10mcds/mē p<0.05; t0=176.5,V versus t28=70.0,V at 2500mcds/mē p<0.05; t0=140.3,V versus t28=40.0,V at 25000mcds/mē p=0.057). The ERG a-wave amplitudes and latencies were also significantly lowered at 2500mcds/mē in eyes treated with ICG (amplitude means: t0=45.0,V versus t28=23,V p<0.05; latency means: t0=7.6msec versus t28=9.5msec p<0.01). Conclusions: This study shows a side effect of ICG on retinal function four weeks after a transient retinal exposure. TA and TB could be considered as interesting alternatives to ICG for macular surgery. [source] Age-related changes in BAER at different click rates from neonates to adultsACTA PAEDIATRICA, Issue 8 2009Ze Dong Jiang Abstract Aim:, To characterize age-related changes in brainstem auditory evoked response (BAER) at different click rates from neonates to adults. Methods:, BAER was studied at repetition rates 11,91/sec of clicks in 165 normal neonates and children of various ages and 29 young adults. Results:, BAER wave latencies and inter-peak intervals increased linearly with increasing click rate at all ages. The younger was the age, the greater were BAER click rate-dependent changes. At 9 months and younger, the slopes of latency- and interval-rate functions were all significantly greater than in the adults (all p < 0.01). The slopes of wave I latency- and I,III interval-rate functions at 1,2 years and older were similar to those in adults. The slopes of wave III and V latency-rate functions and I,V and III,V interval-rate function at 3,4 years and older did not differ significantly from those in adults. Conclusion:, BAER is affected by stimulus rate more in younger children than in the older. Adult-like rate-dependent changes are reached at 1,2 years for wave I latency and I,III interval, and 3,4 years for wave III and V latencies and I,V and III,V intervals. Our BAER data at different click rates provide normal references for subjects of various ages. [source] Comparison of brainstem auditory evoked responses recorded at different presentation rates of clicks in term neonates after asphyxiaACTA PAEDIATRICA, Issue 12 2001ZD Jiang This study examined whether high presentation rates of clicks while recording brainstem auditory evoked responses (BAER) can improve the detection of central auditory impairment in asphyxiated neonates using the BAER. The BAER was analysed at different presentation rates of clicks within the first week after birth in 38 term neonates who suffered perinatal asphyxia. At the routinely used 21 s,1 clicks all BAER wave latencies increased significantly (ANOVA, p < 0.05-0.01). After excluding five neonates who had a significantly elevated BAER threshold, only wave V latency increased slightly (p < 0.05). The interpeak intervals of I,V and III,V also increased slightly (both p < 0.05). Similar results were found at 51 s,1 clicks. As the clicks were increased to 91 s,1, the III,V interval increased more significantly (p < 0.01) and the III,V/I,III interval ratio also increased significantly (p < 0.01). In particular, wave V amplitude reduced more significantly than that in normal term controls (p < 0.01). Compared with values in the controls, wave V amplitude reduced by 4.5%, 12.2% and 24.7% at 21, 51 and 91 s,1 clicks, respectively. Conclusion: Although a moderate increase in the rate (e.g. 51 s,1) while recording the BAER did not improve the detection of hypoxic-ischaemic auditory impairment, a significant increase (e.g. 91 s,1) did, which mainly indicates an abnormal reduction in wave V amplitude. [source] | ||||||||||