Comparison of long-latency reflex and mixed nerve silent period responses in various hypokinetic movement disorders = A hosszú latenciájú reflexválaszoknak és a kevert idegek csendes periódusainak összehasonlítása különböző hipokinetikus mozgási rendellenességekben

Background and purpose – Long-latency reflex and mixed nerve silent period responses are electrophysiological methods to study the sensorimotor functions of the central nervous system. Here we aimed to study longlatency reflexes and mixed nerve silent period responses in different types of hypokinetic movement disorders in order to find an electrophysiological landmark to distinguish them. Methods – We included 39 patients with idiopathic Parkinson’s disease (IPD), 12 patients with multiple system atrophy (MSA), 10 patients with corticobasal syndrome (CBS), 5 patients with progressive supranuclear palsy (PSP) and 26 healthy participants. We recorded the segmental reflex, the long-latency reflexes and the mixed nerve silent period responses for each participant. Results – C reflex, long-latency reflex-I and long-latency reflex-III responses were not obtained in any patients with PSP. Long-latency reflex amplitude/ F amplitude ratio was significantly lower in patients with IPD and PSP compared to healthy individuals (p=0.036, p=0.006 respectively). The mixed nerve silent period end latencies were significantly longer in IPD, MSA, CBS groups compared to the healthy individuals (p=0.026, p=0.050, p=0.008 respectively). Conclusion – We suggest that recording long-latency reflex, particularly C reflex responses may provide promising results in distinction of CBS and MSA from PSP. Prospective studies with clinical findings and brainstem reflexes may offer more information. = Háttér és cél – A hosszú latenciájú reflexválaszoknak és a kevert idegek csendes periódusainak elektrofiziológiai módszerekkel való vizsgálata lehetôvé teszi a központi ideg rendszer szenzomotoros funkcióinak tanulmányozását. Jelen vizsgálatunk célja a hosszú latenciájú reflexválaszok és a kevert idegek csendes periódusainak összehasonlí - tása volt különbözô hipokinetikus mozgási rendelle nes sé - gekben, annak érdekében, hogy olyan elektrofiziológiai jeleket ta lál junk, amelyek alkalmasak megkülönböz te - tésükre. Módszerek – 39 idiopathiás Parkinson-kórban (IPD), 12 mul tiszisztémás atrófiában (MSA), 10 corticobasalis szind - rómában (CBS), 5 progresszív szupranukleáris paresisben (PSP) szenvedô beteget és 26 egészséges kontrollszemélyt vontunk be a vizsgálatba. Min den résztvevô esetében rögzítettük a szegmentális reflexet, a hosszú latenciájú reflexeket és a kevert idegek csendes periódusait. Eredmények – C-reflex-, hosszú latenciájú reflex-I- és hosszú latenciájú reflex-III-válaszokat nem kaptunk PSPben szenvedô betegeknél. A hosszú latenciájú reflex - amplitúdó/F-amplitúdó arány szignifikánsan alacsonyabb volt az IPD- és a PSP-bete geknél, mint az egészséges kont - rollszemélyek nél (p=0,036, p=0,006). A kevert idegek csendes perió du sának végén je lent kezô latenciák szignifikánsan hosszabbak voltak az IPD-, az MSA- és a CBScsoportokban, mint az egészséges kont roll személyeknél (p=0,026, p=0,050, p=0,008). Következtetés – Véleményünk szerint a hosszú latenciájú ref lexválaszok, különösen a C-reflex-válaszok rögzítése ígé retes eszköz lehet a CBS és az MSA PSP-tôl való megkülönböztetésében. A klinikai leleteket és az agytörzsi reflex válaszokat egyaránt tartalmazó, prospektív vizsgálatok további információt nyújthatnak

What Happens in the Other Eye? Blink Reflex Alterations in Contralateral Side After Facial Palsy

Alterations in blink reflex excitability may occur in the contralateral side (CLS) and in the symptomatic side after peripheral facial palsy (PFP). In this study, the alterations of blink reflex in CLS were evaluated in cases with PFP who showed "three different types" of recovery. For this purpose, the R2 response area and recovery curve of the blink reflex were evaluated. The study included 51 patients suffering from PFP and 20 age- and sex-matched healthy controls. Cases with PFP were divided into three groups: patients with PFP with partially cured and accompanied by synkinesis (postfacial syndrome), patients with PFP with residual weakness, and patients who suffered from recurrent PFP. All three groups' R2 values of CLS were compared with the values of controls and patients who had synkinesis. The CLS of all three groups' R2 area values were found to be significantly higher when compared with controls. These values were found to be highest in patients who suffered from recurrent PFP. Hyperexcitability occurs in CLS after PFP and this is highest in patients who suffer from recurrent PFP. It suggested that the contralateral reorganization caused by peripheral nerve damage correlates with the severity of the lesion and the recurrence of axon damage enhances the excitability of the reflex cycle, which affects the contralateral facial nucleus

Auditory-evoked masseter inhibitory reflex

We aimed to investigate auditory-evoked masseter inhibitory reflex and discuss possible auditory-trigeminal pathways in brainstem. Our study population consisted of 21 healthy volunteers (age-matched 7 males and 14 females). Bilateral electrical blink reflex (BR), auditory blink reflexes (ABR) and electrical MIR (MIR) were studied. After obtaining normal potentials, auditory MIR (AMIR) was studied. Electrical blink reflexes had two components as R1 and R2, and ABR had one evoked potential in all volunteers. There was no significant difference between gender, nor between right- and left-sided BR and ABR. The mean latency of ABR responses were shorter than latencies of R2 phase of BR (p = 0.013 for left-sided responses, p = 0.035 for right-sided responses). Electrical stimulation revealed two suppression periods (SP1 and SP2) in MIR responses bilaterally in all volunteers. Auditory stimulation evoked typical two suppression periods only in 11 subjects (5 males, 6 females). The mean latency of SP1 component of AMIR was significantly longer than those of MIR bilaterally in both males and females, while the SP2 component had a shorter onset. The durations of SP1, SP2 and total SP were always shorter than those obtained in MIR with smaller degree of suppressions. None of the MIR or AMIR responses showed significance difference between sexes. We assume that auditory-evoked MIR might share the similar interneurons as with other electrical or nociceptive stimulation, which connects cochlear-trigeminal neurons via pontine reticular system to premotor area for masseter muscle. (C) 2010 Elsevier Ireland Ltd. All rights reserved

R-3 COMPONENT OF THE EYE BLINK REFLEX IN VARIOUS PAINFUL CONDITIONS

Objective: We investigated R1, R2 and especially R3 responses of blink reflex in various painful conditions to understand the eligibility of R3 component in electrophysiological pain studies

THE EFFECT OF SHORT-TERM VIBRATION ON SOMATOSENSORY TEMPORAL DISCRIMINATION THRESHOLD

Objective: This study will evaluate the changes in the somatosensory temporal discrimination threshold (STDT) after focal muscle vibration. The hypothesis was that the STDT, which is related to the functions of basal ganglia and somatosensory cortex, would deteriorate during application of peripheral muscle vibration if it had indirect central effects

Mentalis muscle related reflexes

The mentalis muscle (MM) arises from the incisive fossa of the mandible, raises and protrudes the lower lip. Here, we aim to characterize responses obtained from MM by supraorbital and median electrical as well as auditory stimuli in a group of 16 healthy volunteers who did not have clinical palmomental reflex. Reflex activities were recorded from the MM and orbicularis oculi (O.oc) after supraorbital and median electrical as well as auditory stimuli. Response rates over MM were consistent after each stimulus, however, mean latencies of MM response were longer than O.oc responses by all stimulation modalities. Shapes and amplitudes of responses from O.oc and MM were similar. Based on our findings, we may say that MM motoneurons have connections with trigeminal, vestibulocochlear and lemniscal pathways similar to other facial muscles and electrophysiological recording of MM responses after electrical and auditory stimulation is possible in healthy subjects

Modulation of the excitatory phase following the cutaneous silent period by vibration

Introduction The post-inhibition excitatory phase (E3) of the cutaneous silent period (CSP) is attributed to the resynchronization of motoneuron activity following the inhibitory period but there is also evidence that a somatosensory startle reflex may contribute to this phase. We hypothesized that the startle reflex component contained in E3 will decrease during vibration. Methods Sixteen healthy individuals were included in the study. CSP was recorded from slightly contracted right thenar muscles after painful index finger stimulation, before, during, and immediately after vibration. The values of the percentage change of E3 relative to pre-stimulus baseline (E3%) were compared before, during, and after vibration for each individual. Results There was a reduction in E3% during vibration and the values returned to normal immediately after vibration (153.1 +/- 43.5%, 115.2 +/- 30.2%, 154.9 +/- 68.2%, respectively;p = 0.030). Discussion E3 is reduced during vibration in healthy individuals, presumably due to suppression of a reflex component, which is superimposed upon the known resynchronization of motoneurons

The cutaneous silent period in diabetes mellitus

The cutaneous silent period (CSP) may be useful as a method for the evaluation of smaller and unmyelinated fiber dysfunctions. CSP refers to the brief interruption in voluntary contraction that follows strong electrical stimulation of a cutaneous nerve. The aim the present study is to establish whether CSP can be instrumental in the determination of diabetic neuropathy. The nerve conduction studies and CSP evaluations were both used in patients with Diabetes Mellitus and control group. All patients were given clinical neurological examinations for the determination of small-fiber neuropathy (SFN). The CSP values for patients with SFN were compared with values of those without SFN. The nerve conduction velocities had changed unfavorably in diabetic patients. No median nerve CSP reponse could be obtained in two of the diabetic patients. CSP latency (84.6 +/- 14.0) in diabetics was longer than controls (76.2 +/- 13. 1) (p = 0.0 18). The duration of CSP was similar for the two groups (P = 0.46). The CSP latency showed a correlation with routine nerve conduction studies. While the CSP latencies (86.7 +/- 15.8) of patients who were clinically diagnosed with SFN were similar to the latencies (81.3 +/- 10.4) of patients without SFN (p = 0.606), the duration of CSP (44.6 +/- 13.7) in patients with SFN was shorter than the duration (55.3 +/- 12.2) in patients without SFN (p = 0.0 12). These results indicate that eventhough the CSP does not provide any advantage over routine electrodiagnostic studies in determining diabetic neuropathy, still it may be a useful method for the early detection of diabetic SFN. (C) 2007 Elsevier Ireland Ltd. All rights reserved