Bibliothek

X
feed icon rss

Ihre E-Mail wurde erfolgreich gesendet. Bitte prüfen Sie Ihren Maileingang.

Leider ist ein Fehler beim E-Mail-Versand aufgetreten. Bitte versuchen Sie es erneut.

Vorgang fortführen?

Exportieren
  • 1
    Digitale Medien
    Digitale Medien
    Transcranial magnetic stimulation of the human brain: responses in muscles supplied by cranial nerves (1988)
    Springer
    Experimental brain research 71 (1988), S. 623-632 
    Details
    ISSN: 1432-1106
    Schlagwort(e): Magnetic stimulation ; Motor cortex ; Corticonuclear tract ; Cranial nerves
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary The present investigation demonstrates that time-varying magnetic fields induced over the skull elicit distinct types of responses in muscles supplied by the cranial nerves both on the ipsilateral and the contralateral side. When the center of the copper coil was positioned 4 cm lateral to the vertex on a line from the vertex to the external auditory meatus, bilateral responses in the masseter, orbicularis oculi, mentalis, and sternocleidomastoideus muscles with a delay of about 10 to 14 ms after the stimulus occurred. Similar to the transcranially evoked muscle responses in hand muscles, the responses in the cranial muscles can be influenced in latency and amplitude by background excitation. It is concluded that these responses are induced by excitation of the face-associated motor cortex followed by multiple I-waves in the corticonuclear tract with both ipsilateral and contralateral projections to the corresponding motoneurones. Additionally, at higher stimulation strengths “short-latency” ipsilateral responses in muscles supplied by the trigeminal, facial, and accessory nerves occurred which we suggest are induced by direct stimulation of the peripheral cranial nerves in their intracisternal course. The present study confirms the bilateral projection of corticonuclear tracts in awake unanesthetised human subjects which has been observed by electrical stimulation on the exposed cortex during surgical procedures already decades ago. The present investigation will serve as a basis for the assessment of pathophysiological mechanisms involving the corticonuclear system or the peripheral cranial nerves in their proximal parts in awake humans.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00248756
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Artikel (Nationallizenzen)
    Volltext
  • 2
    Digitale Medien
    Digitale Medien
    Reorganisation of descending motor pathways in patients after hemispherectomy and severe hemispheric lesions demonstrated by magnetic brain stimulation (1991)
    Springer
    Experimental brain research 83 (1991), S. 419-426 
    Details
    ISSN: 1432-1106
    Schlagwort(e): Magnetic brain stimulation ; Hemispherectomy ; Corticospinal tract ; Cortico-reticulospinal pathways ; Human
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary Numerous clinical studies on patients after hemispherectomy (HS) have provided clear evidence that two distinct groups can be recognized on the basis of the quality of their motor functions after operation. One of these consists of cases where HS was performed after normal brain maturation, the other of patients where the removed hemisphere was damaged early in life. The post-operative motor function has been found to be much better in the latter group. In the present paper it is demonstrated that in contrast to normal subjects ipsilateral compound muscle action potentials (CMAPs) induced by magnetic stimulation of the one intact motor cortex are present in patients after HS. The amplitudes of ipsilateral CMAPs in the muscles roughly correlate with their individual residual motor capacities and show a proximo-distal gradient. In patients with early brain damage prior to HS, CMAPs had short latencies and large amplitudes, whereas in patients with later acquired brain damage prior to HS, CMAPs had long latencies and small amplitudes. It is suggested that reinforcement of the ipsilateral corticospinal pathway may be responsible for residual motor functions in patients with early brain damage, whereas in patients with later acquired brain damage cortico-reticulospinal pathways may play a dominant role in ipsilateral motor control.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00231167
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Artikel (Nationallizenzen)
    Volltext
  • 3
    Digitale Medien
    Digitale Medien
    Functional organisation of corticonuclear pathways to motoneurones of lower facial muscles in man (1994)
    Springer
    Experimental brain research 101 (1994), S. 465-472 
    Details
    ISSN: 1432-1106
    Schlagwort(e): Magnetic stimulation ; Single motor units ; Lower facial muscles ; Corticobulbar connexions ; Human
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract EMG responses were recorded from lower facial muscles (depressor labii inferioris or depressor anguli oris) of 12 normal subjects after magnetic stimulation of the motor cortex. Using a figure-of-eight stimulating coil, the largest responses were obtained from points around 8–10 cm lateral to the vertex. Usually they were bilateral and had the same latency (11–12 ms) on both sides of the face. Patients with complete Bell's palsy had no response in muscles on the same side as the lesion, indicating that the ipsilateral component to cortical stimulation was not the result of recrossing in the periphery of nerve fibres from the contralateral side. Single-unit studies showed that cortical stimulation produced two phases of motoneuronal facilitation: a short-latency (central motor delay from contralateral cortex to the intracranial portion of the facial nerve, 7.6 ms), short-duration (1– to 2-ms duration peak in the post-stimulus time histogram) input, which was more commonly evoked by contralateral than ipsilateral stimulation; and a longer latency (central delay 〉 15 ms), long-duration input evoked equally well from either hemisphere. The former may represent activity in a predominantly contralateral oligosynaptic corticobulbar pathway; the latter, a polysynaptic indirect (e.g. co-rticotegmento-nuclear) bilateral pathway to lower facial muscles.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00227339
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Artikel (Nationallizenzen)
    Volltext
  • 4
    Digitale Medien
    Digitale Medien
    Complex repetitive discharges in the iliopsoas muscle (1988)
    Springer
    Journal of neurology 235 (1988), S. 411-414 
    Details
    ISSN: 1432-1459
    Schlagwort(e): Electromyography ; Spontaneous activity ; Iliopsoas muscle ; Diabetic polyneuropathies ; Radiculopathies
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary A prospective electromyographic investigation of lower limb muscles in patients with different neurogenic disorders showed that complex repetitive discharges (CRD) were observed predominantly and often only in the iliopsoas muscle. Analysis of the EMG findings in acute and chronic lesions shows that CRD are a feature of a chronic proximal motor axon lesion. Furthermore, the frequently focal occurrence of CRD in the iliopsoas muscle in clinically distal diabetic polyneuropathies suggests that this muscle and its nerves represent a locus minoris resistentiae.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00314483
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Artikel (Nationallizenzen)
    Volltext
  • 5
    Digitale Medien
    Digitale Medien
    Motor responses evoked by magnetic brain stimulation in psychogenic limb weakness: diagnostic value and limitations (1992)
    Springer
    Journal of neurology 239 (1992), S. 251-255 
    Details
    ISSN: 1432-1459
    Schlagwort(e): Magnetic brain stimulation ; Psychogenic weakness ; Central weakness ; Corticospinal tract function
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary The latencies and amplitudes of responses evoked by magnetic brain stimulation (magnetic evoked potentials, MEP) in the first dorsal interosseus and the anterior tibial (TA) muscles were investigated in 15 patients with psychogenic limb weakness and in 50 patients with limb weakness due to established organic central nervous system disease. Of the patients with psychogenic limb weakness, 3 presented with upper limb monopareses, 2 with lower limb monoparesis, 4 with hemipareses, 4 with parapareses and 2 with paraparesis. All patients with psychogenic weakness had MEP in arm and leg muscles with latencies within the normal range. MEP amplitudes were also normal except for 1 patient in whom the response amplitude in the TA of the plegic limb was reduced. In patients with limb weakness due to established organic disease, MEP were frequently but not invariably abnormal. In patients with plegic (i.e. completely paretic, MRC grade 0) muscles due to organic disease, MEP always were clearly abnormal. Normal MEP were sometimes elicited from paretic muscles, more commonly in association with cerebral hemisphere lesions than with spinal lesions. We conclude that psychogenic limb weakness is associated with normal MEP. However, normal MEP in mildly paretic muscles do not definitely exclude organic pathology.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00810346
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Artikel (Nationallizenzen)
    Volltext
  • 6
    Digitale Medien
    Digitale Medien
    Callosal and corticospinal tract function in patients with hydrocephalus: a morphometric and transcranial magnetic stimulation study (1998)
    Springer
    Journal of neurology 245 (1998), S. 280-288 
    Details
    ISSN: 1432-1459
    Schlagwort(e): Key words Corpus callosum ; Corticospinal tract ; Hydrocephalus ; Brain morphometry ; Transcranial magnetic brain stimulation
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract In 15 patients with symptomatic hydrocephalus, pressure-induced morphological changes of the brain and the function of callosal and corticospinal fibres were studied. Morphometry of the corpus callosum (CC) was performed on midsagittal MR images. Focal transcranial magnetic stimulation of the motor cortex was used to assess simultaneously excitatory motor responses in contralateral hand muscle (corticospinally mediated effect) and inhibition of tonic EMG activity in ipsilateral hand muscles (transcallosal inhibition (TI) of the contralateral motor cortex). Before a shunt operation, the midsagittal area of the CC was reduced by 34% on average. The height and, to a lesser degree the length, of the CC were increased before the shunt operation. Thresholds and central motor latencies of corticospinally mediated responses were normal, response amplitudes were smaller than in normal subjects. Motor thresholds increased from 38, SD 5 to 52, SD 8% (P〈0.01) within 7 days after ventricular drainage, reflecting the increase in the distance between stimulation coil and brain. The threshold increase paralleled a restoration of normal anatomical conditions within 7 days after shunt operation and the improvement of motor symptoms and might be a predictor of successful decompression. Transcallosal inhibition could be elicited in all patients. The measurements of TI lay within the normal range except the duration, which was prolonged in 73% of 15 patients before shunt operation as a probable indicator of an increased dispersion of callosal conduction. The normalization of the area and shape of the CC after shunt operation and the normal corticospinal and callosal conduction times exclude degeneration, demyelination or functional block of a large proportion of callosal or corticospinal tract fibres or a substantial loss of nerve cells in motor cortex.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/s004150050219
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Artikel (Nationallizenzen)
    Volltext
  • 7
    Digitale Medien
    Digitale Medien
    Reply (1995)
    Springer
    Journal of neurology 242 (1995), S. 715-715 
    Details
    ISSN: 1432-1459
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00866927
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Artikel (Nationallizenzen)
    Volltext
  • 8
    Digitale Medien
    Digitale Medien
    Investigation of unilateral facial weakness: magnetic stimulation of the proximal facial nerve and of the face-associated motor cortex (1989)
    Springer
    Journal of neurology 236 (1989), S. 102-107 
    Details
    ISSN: 1432-1459
    Schlagwort(e): Magnetic stimulation ; Motor cortex ; Corticonuclear tract ; Facial nerve ; Bell's palsy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary Twenty-four patients with unilateral facial weakness of various aetiologies were investigated using a magnetic stimulator to stimulate the proximal segment of the facial nerve directly (short latency response) and also to activate the facial motoneurons bilaterally via corticonuclear pathways by placing the stimulating coil over the motor cortex (long latency responses). Electromyographic recordings were taken from both mentalis muscles using concentric needle electrodes. Seventeen patients were investigated at various times after onset of idiopathic facial palsy (Bell's palsy). In the acute stage (less than 5 days after onset) short and long latency responses on the paretic side were abnormal, being absent in all but one patient, in whom the short latency response was delayed. These abnormal responses were the earliest neurographic correlate for nerve conduction block. In 4 out of 9 patients seen up to 30 days after onset of palsy, trans-synaptically evoked long latency responses were absent. In patients examined more than 2 months after onset, long latency responses could always be obtained and, in 5 of 8 patients, short latency responses could also be elicited, indicating a return of the direct excitability of the nerve. Five patients with cerebral hemisphere lesions causing mild unilateral facial weakness had absent long latency responses when stimulating over the affected hemisphere, but normal bilateral long latency responses following stimulation over the unaffected cerebral hemisphere; short latency responses were normal. Magnetic stimulation of the brain and of the facial nerve can differentiate between central and peripheral causes of unilateral facial weakness and may prove useful in the early assessment of the degree of conduction block in Bell's palsy.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00314405
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Artikel (Nationallizenzen)
    Volltext
  • 9
    Digitale Medien
    Digitale Medien
    Scalp potentials recorded over the sensorimotor region following magnetic stimulation over the cerebellum in man: Considerations about the activated structures and their potential diagnostic use (1995)
    Springer
    Journal of neurology 242 (1995), S. 109-112 
    Details
    ISSN: 1432-1459
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00887826
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Artikel (Nationallizenzen)
    Volltext
  • 10
    Digitale Medien
    Digitale Medien
    Impairment of callosal and corticospinal system function in adolescents with early-treated phenylketonuria: a transcranial magnetic stimulation study (1999)
    Springer
    Journal of neurology 246 (1999), S. 21-30 
    Details
    ISSN: 1432-1459
    Schlagwort(e): Key words Corpus callosum ; Corticospinal tract ; Phenylketonuria ; Focal transcranial magnetic brain ; stimulation
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract The transcranial activation and the conduction properties of corticospinal and callosal neurons were investigated in 12 early-treated adolescents (aged 17.3, SD 3.5 years; range 14–27 years) with phenylketonuria (PKU) by focal transcranial magnetic stimulation (fTMS) of the motor cortex. The patients had no functionally relevant motor disturbances in daily life or on clinical testing. Corticospinally mediated excitatory (response thresholds, amplitudes, central motor latencies) and inhibitory [duration of postexcitatory inhibition (PI)] effects of fTMS were investigated in contralateral hand muscles. Transcallosal inhibition (TI) (onset latency, duration, transcallosal latency) of tonic electromyographic (EMG) activity was tested in ipsilateral muscles. Peripheral motor latencies were determined for responses elicited by magnetic stimulation over cervical nerve roots. Ten normal subjects served as controls. Since in all PKU patients, central and peripheral motor latencies were normal, no neurophysiological indication of a demyelination of corticospinal or peripheral motor fibres was found. However, cortical thresholds of corticospinally mediated responses were increased (52.1, SD 11.6% versus 35.0, SD 7.4% of maximum stimulator output; P 〈 0.05; n = 24 hands) and their amplitudes reduced (2.9, SD 1.4 mV versus 6.1, SD 1.5 mV, P 〈 0.05). The duration of PI was shortened (132, SD 53 ms versus 178, SD 57 ms; P 〈 0.05). TI was absent in 37.5% of the investigated hands or tended to be weak. When TI was present, its onset latencies (38.0, SD 3.6 ms versus 34.7, SD 3.3 ms) and transcallosal latencies were prolonged (18.5, SD 3.8 ms versus 14.8, SD 3.2 ms), while its duration was normal. These abnormal excitatory and inhibitory effects of fTMS suggest a reduced susceptibility of cortical excitatory and inhibitory neuronal structures compatible with a loss of neurons or a rarefication of their dendrites.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/s004150050301
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Artikel (Nationallizenzen)
    Volltext
Schließen ⊗
Diese Webseite nutzt Cookies und das Analyse-Tool Matomo. Weitere Informationen finden Sie hier...