Publications by authors named "Michael Faist"

9 Publications

  • Page 1 of 1

Spongiform encephalopathy in siblings with no evidence of protease-resistant prion protein or a mutation in the prion protein gene.

J Neurol 2013 Jul 2;260(7):1871-9. Epub 2013 Apr 2.

National Reference Center for TSE Surveillance, Department of Neurology, University Medical Center Göttingen, Robert-Koch Str. 40, 37075 Göttingen, Germany.

We discuss relevant aspects in two siblings with a neurodegenerative process of unclear aetiology who developed progressive dementia with global aphasia and hyperoral behaviour at the ages of 39 and 46 years and who died 6 and 5 years after disease onset. The cases were reported to the National Reference Center for TSE Surveillance in Göttingen, Germany. Detailed clinical examinations, CSF, blood samples, and copies of the important diagnostic tests (magnetic resonance imaging, electroencephalogram, laboratory tests) were obtained. Further neuropathological and genetic analyses were performed. Cerebral magnetic resonance imaging of both siblings showed prominent changes in signal intensity, especially in the left medial temporal cortex, but also the hippocampal formation. Neuropathological examination revealed spongiform changes, neuronal loss, and astrocytic gliosis, which are typical in Creutzfeldt-Jakob disease. However, no prion protein deposits were detectable by immunohistochemical analysis, Western blot, or PET blot, though abundant tau protein deposits were observed. A mutation in the coding region of the prion protein genes of both siblings was excluded. A detailed search of the literature revealed no other cases with a similar clinical and neuropathological appearance. While the disease aetiology remains unclear, the findings point to a neurodegenerative process and most likely a genetic disease.
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http://dx.doi.org/10.1007/s00415-013-6897-zDOI Listing
July 2013

Changes in soleus H-reflex modulation after treadmill training in children with cerebral palsy.

Brain 2009 Jan 3;132(Pt 1):37-44. Epub 2008 Nov 3.

Department of Neurology and Clinical Neurophysiology, University Hospital Freiburg, Freiburg, Germany.

In healthy children, short latency leg muscle reflexes are profoundly modulated throughout the step cycle in a functionally meaningful way and contribute to the electromyographic (EMG) pattern observed during gait. With maturation of the corticospinal tract, the reflex amplitudes are depressed via supraspinal inhibitory mechanisms. In the soleus muscle the rhythmic part of the modulation pattern is present in children with cerebral palsy (CP), but the development of tonic depression with increasing age, as seen in healthy children, is disturbed. Treadmill training clinically improves the walking pattern in children with CP. Presuming that short latency reflexes contribute significantly to the walking pattern, a change in the modulation may occur after training. The aim of this study was to assess whether treadmill training also improves the soleus reflex modulation during gait in children with CP. Seven children with CP underwent brief treadmill training for 10 min a day over 10 consecutive days; all of them were functional walkers. Soleus Hoffmann (H-) reflexes were investigated during walking on a treadmill before the first, and one day after the last, training session. Treadmill training led to a considerable clinical improvement in gait velocity. After 10 days of training, soleus H-reflexes during gait were almost completely depressed during the swing phase. The complete suppression of the soleus H-reflex during the swing phase, which is also exhibited by healthy subjects, could reflect an improvement towards a functionally more useful pattern. In conclusion, treadmill training can induce changes in the modulation of short latency reflexes during gait.
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http://dx.doi.org/10.1093/brain/awn287DOI Listing
January 2009

Altered cortical inhibitory function in children with spastic diplegia: a TMS study.

Exp Brain Res 2008 Apr 23;186(4):611-8. Epub 2008 Jan 23.

Department of Paediatrics and Adolescent Medicine, Division of Neuropaediatrics and Muscular Disorders, University Hospital Freiburg, Mathildenstrasse 1, 79106 Freiburg, Germany.

Periventricular leukomalacia (PVL) is the most frequent cause of spastic diplegia. The movement disorder is attributed to damage to the corticospinal tract, but there is increasing evidence of additional cortical dysfunction associated with PVL. Aim of the present study was to evaluate the integrity of the corticospinal tract and cortical inhibitory function using transcranial magnetic stimulation. Fifteen children with bilateral PVL and spastic diplegia and twenty-two healthy children underwent single-pulse stimulations to the right tibial anterior muscle. We compared central motor conduction time and amplitudes of motor evoked potentials as markers for corticospinal integrity and the postexcitatory silent period (SP), representing cortical inhibitory interneurons. The patients' parameters of corticospinal tract function did not differ significantly from those in the control children. In contrast, the SP was significantly shortened in children with PVL (mean 25.6 +/- 6.9 ms; controls: mean 47.6 +/- 23.2 ms, P = 0.018). This suggests cortical involvement with reduced cortical inhibitory function in PVL. This could be due to impaired functioning of the cortical interneurons themselves, or to decreased input from activating fibres, e.g. thalamocortical or cortico-cortical connections.
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http://dx.doi.org/10.1007/s00221-007-1267-7DOI Listing
April 2008

Reply to Chmielewski and Snyder-Mackler.

J Neurophysiol 2007 Oct;98(4):2493

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http://dx.doi.org/10.1152/jn.00477.2007DOI Listing
October 2007

Modulation of soleus H-reflexes during gait in children with cerebral palsy.

J Neurophysiol 2007 Dec 3;98(6):3263-8. Epub 2007 Oct 3.

Department of Neurology and Clinical Neurophysiology, University Hospital Freiburg, Breisacher Strasse 64, 79106, Freiburg, Germany.

In healthy adults, soleus H-reflexes are rhythmically modulated and generally depressed during gait compared with rest. From ages 6 to 13 yr, there is a progressive increase in the tonic inhibition of H-reflexes during walking, especially during the stance phase of the step cycle. In adults, rhythmic modulation and tonic depression are severely disturbed after bilateral spinal lesions but remain partly preserved after unilateral cerebral lesions. Children with diplegic cerebral palsy (CP) suffer from a bilateral supraspinal lesion of the corticospinal tract that occurs before the maturation of the CNS is complete. If supraspinal structures are involved in the tonic, but not rhythmic, age-dependent reflex depression, it could be hypothesized that the tonic reflex depression with age is disturbed in CP, whereas the rhythmic part of the modulation remains unaffected. To test this hypothesis, soleus H-reflexes were assessed during gait in 16 CP children aged 5-11 and 15-16 and compared with 25 age-matched healthy children walking at similar velocities. Although the rhythmic part of the modulation pattern was present in CP, there was no significant tonic reflex depression with age, thus reflecting a lack of maturation of the corticospinal tract. It is argued the rhythmic part of the modulation may be generated on a spinal or brain stem level and is therefore not affected by the bilateral supraspinal lesion, whereas the tonic depression that occurs with maturation of the CNS is under supraspinal control. In conclusion, the supraspinal structures affected in CP are therefore likely involved in this age-dependent tonic depression.
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http://dx.doi.org/10.1152/jn.00471.2007DOI Listing
December 2007

Therapeutic cooling: no effect on hamstring reflexes and knee stability.

Med Sci Sports Exerc 2006 Jul;38(7):1329-34

Institute of Orthopaedic Research and Biomechanics, University of Ulm, Ulm, Germany.

Purpose: Stretch reflexes contribute to joint stiffness, but the effects of therapeutic cooling on these reflexes are unknown. Therapeutic cooling is frequently used in knee rehabilitation, for instance, after rupture of the anterior cruciate ligament. Cooling a joint can affect nerve conduction velocity and the function of sensory organs. Such changes in neuromuscular coupling could reduce knee stability and increase the risk of knee injury. The aim of the present study was to evaluate whether there are negative effects of knee cooling on the hamstring short and medium latency reflex responses or on the anterior tibia trajectory after mechanically induced tibia translation.

Methods: In 15 healthy volunteers, the latency and size of short latency and medium latency reflex responses of hamstring muscles were assessed before and after 20 min of cold therapy of the knee joint as applied in rehabilitation. Reflex responses were evoked by a mechanically induced posterior-anterior tibia translation during standing. Reflexes were recorded by surface electromyography. The distance of anterior tibia motion and its velocity were assessed by potentiometric position transducer.

Results: Local cold therapy of the knee did not alter the latency or the size of short or medium latency responses. Also, the extent and the velocity of tibia translation were unchanged after knee cooling.

Conclusion: Cold therapy does not seem to adversely influence the spinal reflexes of the hamstrings induced by anterior tibia translation. As neuromuscular coupling was not significantly affected, the cold therapy, as performed in the present study, is not likely to increase the risk of knee injury.
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http://dx.doi.org/10.1249/01.mss.0000227635.86285.3bDOI Listing
July 2006

Direct corticospinal pathways contribute to neuromuscular control of perturbed stance.

J Appl Physiol (1985) 2006 Aug 6;101(2):420-9. Epub 2006 Apr 6.

Univ. of Freiburg, Dept. of Sport Science, Schwarzwaldstr. 175, 79117 Freiburg i.Br., Germany.

The antigravity soleus muscle (Sol) is crucial for compensation of stance perturbation. A corticospinal contribution to the compensatory response of the Sol is under debate. The present study assessed spinal, corticospinal, and cortical excitability at the peaks of short- (SLR), medium- (MLR), and long-latency responses (LLR) after posterior translation of the feet. Transcranial magnetic stimulation (TMS) and peripheral nerve stimulation were individually adjusted so that the peaks of either motor evoked potential (MEP) or H reflex coincided with peaks of SLR, MLR, and LLR, respectively. The influence of specific, presumably direct, corticospinal pathways was investigated by H-reflex conditioning. When TMS was triggered so that the MEP arrived in the Sol at the same time as the peaks of SLR and MLR, EMG remained unaffected. Enhanced EMG was observed when the MEP coincided with the LLR peak (P < 0.001). Similarly, conditioning of the H reflex by subthreshold TMS facilitated H reflexes only at LLR (P < 0.001). The earliest facilitation after perturbation occurred after 86 ms. The TMS-induced H-reflex facilitation at LLR suggests that increased cortical excitability contributes to the augmentation of the LLR peaks. This provides evidence that the LLR in the Sol muscle is at least partly transcortical, involving direct corticospinal pathways. Additionally, these results demonstrate that approximately 86 ms after perturbation, postural compensatory responses are cortically mediated.
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http://dx.doi.org/10.1152/japplphysiol.01447.2005DOI Listing
August 2006

Interstitial 125I radiosurgery of supratentorial de novo WHO Grade 2 astrocytoma and oligoastrocytoma in adults: long-term results and prognostic factors.

Cancer 2006 Mar;106(6):1372-81

Department of Neurosurgery, Grosshadern Clinic, Ludwig-Maximilians-University, Marchioninistrasse 15, 81377 Munich, Germany.

Background: Detailed long-term outcome data are not available for adult patients with World Health Organization (WHO) Grade 2 astrocytoma or oligoastrocytoma.

Methods: A previously published short-term data set of 239 adult patients with circumscribed de novo supratentorial astrocytoma (187 patients) and oligoastrocytoma (52 patients) treated with interstitial iodine-125 ((125)I) radiosurgery as primary treatment (1979-1992) was revisited. Survival, progression-free survival, functionally independent survival, postrecurrence survival, and time to malignant transformation were estimated with the Kaplan-Meier method. Prognostic factors were obtained from the Cox multivariate proportional hazards model.

Results: Five-, 10-, and 15-year survival was 56%, 37%, and 26%, respectively (median follow-up, 10.3 yrs). Progression-free survival was 45%, 21%, and 14%, respectively. The corresponding malignant transformation rates were 33%, 54%, and 67%. No leveling off of the Kaplan-Meier curves could be observed for any of the chosen endpoints. Age > 50 years, a tumor volume > 20 mL, and/or a Karnofsky score < or = 80 were associated with decreased survival or progression-free survival. Age > 35 years and/or a tumor volume > 20 mL increased risk of malignant transformation. Prognostic factors determined subsets of patients with 10-year survival ranging from as low as 6% to as high as 55% and progression-free survival ranging 1-31%.

Conclusions: Long-term tumor stabilization is rare. As outcome is mainly determined by treatment-independent factors, minimization of any treatment-related risk must be considered essential.
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http://dx.doi.org/10.1002/cncr.21750DOI Listing
March 2006

Carotid cavernous fistula: embolization via a bilateral superior ophthalmic vein approach.

AJNR Am J Neuroradiol 2002 Nov-Dec;23(10):1736-8

Department of Neuroradiology, University of Freiburg, Freiburg, Germany.

We report the case of a 74-year-old woman with a complex indirect (Barrow D) carotid cavernous sinus fistula. The patient was treated incrementally and finally cured by a rarely reported bilateral retrograde direct transvenous approach via the superior ophthalmic vein. The treatment of the complex carotid cavernous fistula with multiple bilateral fistula points showed additional complexity due to a partially thrombosed left superior ophthalmic vein, which required a combined microsurgical and endovascular treatment, showing that treatment can be achieved, if necessary, by catheterization of a thrombosed orbital vein.
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March 2003