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ABSTRACT: Age and height influence on sural sensory nerve action potential (SNAP) have been studied separately. Our aim was to develop an equation for predicting the lower normal limits as a function of both these factors.
One hundred fifty-eight healthy volunteers, 63 male, with mean age 45.8 and mean height 167.3 without symptoms or signs of peripheral neuropathy participated in the study. The sural SNAP was recorded at the level of the ankle joint, just posterior to the lateral malleolus, using surface electrodes. Antidromic supramaximal stimulation was performed 13 cm proximally at the posterior midcalf.
The mean sural SNAP amplitude was 19.9+/-6.89 microV. Pearson linear correlation showed a negative correlation of the SNAP amplitude with age (R=-0.22, p=0.005) and height (R=-0.19, p=0.03). The multiple linear regression model was applied for both parameters of age and height with SNAP amplitude as the dependent parameter, producing the following equation: SNAP amplitude=62.45-0.1447 x Age-0.2147 x Height.
Using our normal data, the computed lower limits of the 95% prediction interval for the sural SNAP amplitude of an individual subject, depending on his age and height, were calculated.
The individualized normal values provided by our equation are essential for the correct interpretation of sural nerve studies.
Clinical neurophysiology: official journal of the International Federation of Clinical Neurophysiology 04/2010; 121(4):561-3. · 3.12 Impact Factor
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G Koutsis,
M E Evangelopoulos,
E Andreadou, D Mandellos,
G Karachalios,
C Potagas,
E Karantoni,
M Karouli,
C Chrysovitsanou,
D Vassilopoulos,
C Sfagos
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ABSTRACT: The onset of multiple sclerosis (MS) in Greece has not been systematically studied. We sought to provide data on the onset of MS in Greece with detailed information regarding initial symptoms, and to confirm the prognostic significance of demographic and clinical factors at onset.
We studied 1,034 consecutive patients with MS and independently assessed 265 patients 'seen at onset'. We used the MS severity score and survival analysis (time to reach an Expanded Disability Status Scale score of 4.0) to evaluate the prognostic significance of factors at onset.
Female-to-male ratio was 1.9:1 and mean age at onset was 30.7 +/- 9.9 years. MS was primary progressive in 9.6%. Initial symptoms were optic neuritis in 20.1%, brainstem dysfunction in 14.7%, dysfunction of long tracts in 49.3%, cerebral dysfunction in 1% and a combination of symptoms in 14.9%. In 'seen at onset' patients, detailed data on initial symptoms are presented. Female gender, earlier age at onset, 'bout onset' and onset with optic neuritis were associated with less severe disease and longer time to disability.
The onset of MS in Greece is similar to Western populations. Initial symptoms are within the expected spectrum. Prognostic significance of factors at onset is as previously identified.
European Neurology 01/2010; 63(6):350-6. · 1.81 Impact Factor
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ABSTRACT: In this follow-up study of approximately 18 months we assessed parameters of medical management in a sample of 70 patients suffering from benign paroxysmal positional vertigo.
Apart from demographic data, we evaluated the time interval from the appearance of the first symptoms until a diagnostic positional manoeuvre was performed, the efficacy of liberatory manoeuvres, the prescription of medication, the use of technical diagnostic resources and the relapse rate.
None of the patients had received a diagnostic positioning test until then. Moreover, in one out of three cases a further unnecessary technical diagnostic procedure was carried out. There was a tendency for the right labyrinth to be more frequently affected, a fact that was statistically independent from age and sex, as well as from overall prognosis, which was characterized by a 15.6% recurrence rate. All patients with manifest positional nystagmus were successfully treated: 87.2% immediately after the repositioning manoeuvre and the rest within 10 days by self-performing Brandt-Daroff exercises. Our retrospective analysis revealed that, given a normal neuro-otological examination, a typical medical history without manifest positioning nystagmus leads safely to the correct diagnosis.
The delay between the onset of symptoms and the diagnosis of BPPV is very often unduly long. A focused medical history may be diagnostic even in the absence of nystagmus during the Dix-Hallpike manoeuvre.
HNO 04/2007; 55(3):190-4. · 0.40 Impact Factor
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ABSTRACT: HintergrundIn der vorliegenden Verlaufsstudie von durchschnittlich 18Monaten wurden Parameter der rztlichen Versorgung von Patienten mit benignem paroxysmalen Lagerungsschwindel (BPLS) an einer Stichprobe von 70Patienten erfasst.MethodeNeben demographischen Daten wurden das Zeitintervall bis zur Diagnosestellung, die Hufigkeit und die Effektivitt von therapeutischen Lagerungen, die Inanspruchnahme von medikamentsen und apparativen Manahmen und die Rezidivrate quantitativ evaluiert.ErgebnisseWhrend eine diagnostische Lagerungsprobe bis zur berweisung bei keinem der Patienten durchgefhrt worden war, bekam einer von 3Fllen eine andere, nichtindizierte, apparative Untersuchung verordnet. Das rechte Labyrinth war unabhngig von Alter und Geschlecht tendenziell hufiger betroffen. Das hing nicht mit der Prognose zusammen, die in der Gesamtkohorte von einer 15,6%igen Rezidivrate gekennzeichnet war. Alle Patienten mit manifesten Lagerungsnystagmus wurden entweder akut nach dem Befreiungsmanver (87,2%) oder sptestens nach 10Tagen mit Hilfe von Brandt-Daroff-bungen beschwerdefrei. Die retrospektive Betrachtung zeigte, dass auch eine typische Anamnese ohne manifesten Lagerungsnystagmus mit hoher Sicherheit die Diagnose BPLS erlaubt, vorausgesetzt, dass die sonstige neuro-otologische Untersuchung unauffllig ist.SchlussfolgerungDie Zeit vom Auftreten der Symptome bis zur Diagnosestellung vom BPLS erweist sich sehr oft als unerwartet lang. Die strukturierte Anamneseerhebung kann zur Diagnose fhren, auch wenn die Lagerungsproben unauffllig sind.BackgroundIn this follow-up study of approximately 18months we assessed parameters of medical management in a sample of 70 patients suffering from benign paroxysmal positional vertigo.MethodsApart from demographic data, we evaluated the time interval from the appearance of the first symptoms until a diagnostic positional manoeuvre was performed, the efficacy of liberatory manoeuvres, the prescription of medication, the use of technical diagnostic resources and the relapse rate.ResultsNone of the patients had received a diagnostic positioning test until then. Moreover, in one out of three cases a further unnecessary technical diagnostic procedure was carried out. There was a tendency for the right labyrinth to be more frequently affected, a fact that was statistically independent from age and sex, as well as from overall prognosis, which was characterized by a 15.6% recurrence rate. All patients with manifest positional nystagmus were successfully treated: 87.2% immediately after the repositioning manoeuvre and the rest within 10days by self-performing Brandt-Daroff exercises. Our retrospective analysis revealed that, given a normal neuro-otological examination, a typical medical history without manifest positioning nystagmus leads safely to the correct diagnosis.ConclusionThe delay between the onset of symptoms and the diagnosis of BPPV is very often unduly long. A focused medical history may be diagnostic even in the absence of nystagmus during the Dix-Hallpike manoeuvre.
HNO 02/2007; 55(3):190-194. · 0.40 Impact Factor
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ABSTRACT: The authors describe two patients suffering from demyelinating central nervous system disease who developed intense vertigo and downbeat nystagmus upon tilting their heads relative to gravity. Brain MRI revealed in both cases a single, small active lesion in the right brachium conjunctivum. The disruption of otolithic signals carried in brachium conjunctivum fibres connecting the fastigial nucleus with the vestibular nuclei is thought to be causatively involved, in agreement with a recently formulated model simulating central positional nystagmus. Insufficient otolithic information results in erroneous adjustment of the Listing's plane in off-vertical head positions, thus producing nystagmic eye movements.
Journal of neurology, neurosurgery, and psychiatry 07/2006; 77(6):790-2. · 4.87 Impact Factor
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ABSTRACT: Cervical stimulation in the horizontal plane induces small and variable eye movements in normal human adults [cervico-ocular reflex (COR)]. In patients with bilateral vestibular loss, the slow COR component increases in amplitude and is thought to contribute to gaze stabilization during head movements, as it is directed opposite to head-on-trunk excursions. The procedures underlying COR slow phase gain enhancement in the compensatory direction remain unclear. We studied the horizontal COR during passive trunk oscillations of +/-16 degrees under the stationary head at 0.1 Hz in ten normal subjects, aged 24-30 years, before and immediately after the application of an adaptation procedure engaging various combinations of sinusoidal neck-proprioceptive, pursuit and retinal slip signals. The duration of this adaptation period was 40 min. A significant gain increase and phase modulation in the compensatory direction were observed in four out of eight subjects after exposing them to neck-proprioceptive stimulation, while pursuing a spot moving in-phase with their trunk. In contrast, staring at the rotating optokinetic pattern or fixating at a stationary spot, while being subjected to combined cervical and optokinetic stimulation, failed to result in any significant modification of the subjects' COR gain and phase. Conceivably, the contribution of the pursuit system was greatly reduced in the paradigm using optokinetic stimulation, while full engagement of retinal slip signals, in the absence of any pursuit contribution, was obtained in the latter adaptation paradigm. These results indicate that motor responses of target tracking rather than simply sensory signals of retinal slip may represent the 'error signal' modifying the COR in humans.
Experimental Brain Research 03/2006; 169(2):153-61. · 2.39 Impact Factor
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ABSTRACT: Cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) is an adult-onset inherited disease, characterised by recurrent strokes, migraine and cognitive impairment. We present the first Greek family with CADASIL, caused by the R153C mutation at exon 4 of the Notch3 gene. A member of this family carrying this mutation was also found to be heterozygotic for the MTHFR mutation, factor V Leiden mutation and had low serum levels of antithrombin III, thus resulting in the appearance of recurrent strokes and thrombotic episodes since his early adulthood. The co-existence of these thrombophilic disorders with CADASIL in a single person poses serious therapeutic dilemmas, as the administration of anticoagulant agents may correlate with increased risk of potentially fatal intracerebral haemorrhage.
Neurological Sciences 11/2005; 26(4):278-81. · 1.32 Impact Factor
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ABSTRACT: We studied the amplitude, latency, and probability of occurrence of fast phases (FP) in darkness to unpredictable vestibular and/or cervical yaw stimulation in normal human subjects. The rotational stimuli were smoothed trapezoidal motion transients of 14 degrees amplitude and 1.25 s duration. Eye position before stimulus application (initial eye position, IEP) was introduced as a variable by asking the subjects to fixate a spot appearing either straight ahead or at 7 degrees eccentric positions. The recordings demonstrated that the generation of FP during vestibular stimulation was facilitated when the whole-body rotation was directed opposite the eccentric IEP. Conversely, FP were attenuated if the whole-body rotation was directed toward the eccentric IEP; i.e., the FP attenuated if they were made to further eccentric positions. Cervical stimulation-induced FP were small and variable in direction when IEP was directed straight ahead before stimulus onset. Eccentric IEPs resulted in large FP, the direction of which was essentially independent of the neck-proprioceptive stimulus. They tended to move the eye toward the primary position, both when the trunk motion under the stationary head was directed toward or away from the IEP. FP dependence on IEP was evident also during head-on-trunk rotations. No consistent interaction between vestibularly and cervically induced FP was found. We conclude that extraretinal eye position signals are able to modify vestibularly evoked reflexive FP in darkness, aiming at minimizing excursions of the eyes away from the primary position. However, neck-induced FP do not relate to specific tasks of stabilization or visual search. By keeping the eyes near the primary position, FP may permit flexibility of orienting responses to incoming stimuli. This recentering bias for both vestibularly and cervically generated FP may represent a visuomotor optimizing strategy.
Experimental Brain Research 09/2002; 145(4):480-8. · 2.39 Impact Factor
