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M Kofler

Publications and source records attributed to M Kofler.

At least 37 records · Page 2Linked to original sources
PubMed1999

Quantitative analysis of masseter and temporalis EMGs: a comparison of anterior guided versus balanced occlusal concepts in patients wearing complete dentures.

The lack of easily measurable, objective physiological activity parameters of the masseter and temporalis muscle during jaw movements in humans has led to the consideration to revise data of surface electromyographies (EMGs) by applying a computerized quantification method. The aim of this follow-up analysis was to get quantitative data out of EMG-records of an earlier study. These records were obtained with two different splints, splint 1 providing an anterior front-canine guidance and splint 2 providing bilateral balanced occlusion. Utilizing a computer aided integration method led to numeric results which statistically proves the prediction of the previous investigation. Applying the integration method, the EMG raw signal was transformed into area-values which enabled a statistical work up of the data. Wilcoxon test statistics shows a significant (P<0.05) lower muscle activity in patients wearing dentures providing anterior front-canine guidance compared to those with balanced occlusion. It is concluded that the neuromuscular activity of the elevator muscles is highly reproducible and that the neuromuscular function is similar in edentulous subjects to that found in people with natural teeth. Furthermore, the study statistically proves earlier visual data that all those subjects, whose muscle activities were observed with anterior guidance (splint 1) compared to bilateral balanced occlusion (splint 2) showed significantly lower values with regard to subjects wearing splint 2.

Centric Relation↗
PubMed1998

Modulation of upper extremity motoneurone excitability following noxious finger tip stimulation in man: a study with transcranial magnetic stimulation.

Little is known about nociceptive reflex mechanisms in the upper limb in humans. To investigate nociceptive effects on spinal motoneurone excitability, a conditioning noxious stimulus was applied to the index finger of five healthy subjects. Motor evoked potentials (MEPs) following contralateral transcranial magnetic stimulation (TMS) were recorded from thenar eminence (TE) and biceps brachii (BB) muscles ipsilateral to finger stimulation. TMS was randomly applied alone or combined with preceding finger stimulation at an interstimulus interval of 100 ms. MEP amplitudes were profoundly suppressed in TE and augmented in BB. We conclude that nociception produces a differential effect on different spinal motoneurone pools, which may be part of a complex protective reflex mechanism in the upper limb of humans.

Adult↗
PubMed1997

The role of motor evoked potentials during surgery for intramedullary spinal cord tumors.

OBJECTIVE: This is a prospective study of the methodology and clinical applications of motor evoked potentials (MEPs) during surgery for intramedullary spinal cord tumors. METHODS: Transcranial electrical stimulation was used to activate corticospinal motoneurons, and the traveling waves of the spinal cord were recorded through catheter-electrodes placed epi- or subdurally. Intraoperative MEP monitoring was performed in 32 consecutive patients (age range, 1-50 yr) undergoing resection of intramedullary spinal cord tumors. In 19 patients, MEPs were present before myelotomy (monitorable group), and in 10 patients, MEPs were absent before myelotomy (unmonitorable group). Placement of an epidural electrode was not possible in two patients, and technical problems prevented recording in one. RESULTS: MEP amplitudes decreased intraoperatively by more than 50% of baseline in three patients, all of whom had postoperative paraplegia. Two of these patients recovered within 1 week after surgery, and one remained paraplegic. None of the patients with preserved MEP amplitude (> 50%) sustained immediate significant postoperative deterioration. Motor function was significantly deteriorated 1 week after surgery in one patient in the monitorable group and in five patients in the unmonitorable group. MEP monitorability was significantly associated with good surgical outcome for adult patients (P < 0.05), although not for pediatric patients (P > 0.6). Preoperative motor status and surgical outcome were not significantly associated for the adult (P = 0.13) or pediatric groups (P > 0.4). CONCLUSION: MEP monitorability was a better predictor of functional outcome than the patient's preoperative motor status for the adult group. Significant predictors of MEP monitorability in the adult group were preoperative motor function (P < 0.01), history of no previous treatment (surgery or irradiation) (P < 0.01), and small tumor size (P < 0.05). Weak associations with monitorable MEPs existed for low-grade tumors (P = 0.09), the presence of baseline somatosensory evoked potentials (P = 0.10), and tumor pathological abnormalities (ependymoma) (P = 0.13). No associations were determined for sex (P > 0.4), associated syrinx (P > 0.3), or tumor location (P > 0.5). In the pediatric group, none of the examined factors were associated with MEP monitorability (P > 0.3). A decline of more than 50% in MEP amplitude during tumor removal should serve as a serious warning sign to the surgeon.

Child↗
PubMed1995

Residual spasticity after selective posterior rhizotomy.

The technique used in performing selective posterior rhizotomies to treat spastic cerebral palsy remains controversial. One hundred nine children who had undergone selective posterior rhizotomies were studied 6 months after their surgery. Their residual spasticity was correlated to the number of roots and whether or not abnormally responding roots were left, in order to validate the surgical technique used to treat spastic cerebral palsy at most neurosurgical centers in North America. The children were divided into three groups (group A: children who had their L2-S1 roots tested and selectively lesioned, n = 15; group B: children who had their L2-S2 roots tested and selectively lesioned, n = 62; group C: children who had their L2-S2 roots tested and whose lesioning was directed both by the response to the stimulation and mapping of the S1-S3 dorsal roots for afferent pudendal nerve activity, n = 32). Clinically significant residual spasticity was present in the gastrocnemius in 33% of the group A children, 11% of the group B children, and 6% of the group C children. We found that there was no significant increase in residual spasticity in the group C children when abnormally responding roots were not cut in order to preserve pudendal nerve activity. This study shows that the inclusion of the S2 roots decreases the amount of residual spasticity (P < 0.01). It also shows that leaving abnormally responding S2 roots to preserve pudendal nerve activity does not affect the incidence of postoperative spasticity (P > 0.1).

Adolescent↗
PubMed1995

Brain stem mapping: neurophysiological localization of motor nuclei on the floor of the fourth ventricle.

We have improved upon a brain stem mapping technique that can be used to locate cranial motor nuclei on the floor of the fourth ventricle. This technique helped to intraoperatively locate the facial colliculus and the motor nuclei of cranial nerves IX/X and XII in 14 patients undergoing removal of brain stem tumors. The motor nuclei of these cranial nerves are usually located relative to specific anatomic landmarks on the ventricular floor. These landmarks were not evident in most patients studied because of the distorting effects of the tumor. Different points of the floor of the fourth ventricle were electrically stimulated while electromyographic responses were recorded with electrodes inserted in the orbicularis oculi and orbicularis oris muscles, the lateral posterior pharyngeal wall, and the intrinsic muscles of tongue. Mapping was performed before and after tumor resection. The technique was found to be useful for locating cranial motor nuclei before tumor resection. It enabled surgeons to avoid damaging the nuclei when entering the brain stem. This technique, however, has certain limitations. Because this is a mapping technique, not a monitoring technique, continuous monitoring during tumor resection was unavailable. Also, the presence of a muscle response after tumor resection did not always indicate preservation of immediate postoperative function (7 days after surgery) because damage to the corticobulbar tract and/or the underlying neural circuitry was not detectable by mapping. Further research is needed to determine the point of stimulation in the functional motor circuitry and the relationship between intraoperative recordings and postoperative function in the long term.

Adolescent↗
PubMed1994

Masseter and temporalis surface electromyography in patients wearing complete dentures comparing anterior and posterior occlusal concepts--a pilot study.

The activity of jaw elevator muscles (masseter and anterior temporal muscle) was studied by surface electromyography in 17 patients wearing complete dentures with anterior-canine guidance. Baseline electromyography was recorded with the dentures and compared to recordings obtained with two different splints adapted to the upper denture, one providing anterior guidance leading to immediate disclusion of the posterior teeth during any jaw movement, the other providing posterior guidance buccally on the working side and lingually on the non-working side (bilaterally balanced occlusion). Recordings were obtained during a sequence of different jaw movements: postural position, maximal tooth contact in intercuspal position, protrusive movement of the mandible (under tooth contact) and during lateral excursions, also carried out under tooth contact. Muscle activity was not significantly different as recorded with dentures only versus with the splints providing anterior guidance. However, a significant increase in activity was observed with bilaterally balanced occlusion. The results of this study in edentulous people are similar to those found in patients with natural teeth.

Aged↗
PubMed1994

Epileptic seizures associated with intrathecal baclofen application.

We report the clinical and EEG findings in three patients presenting with seizures associated with intrathecal baclofen application for treatment of spasticity. All patients had a history of traumatic brain injury, while one patient also suffered a spinal cord injury. Two patients experienced their first seizure following intrathecal baclofen test bolus injection. Another patient had convulsions on two occasions: following postoperative baclofen dose adjustment, and after sleep deprivation. Structural brain disease seems prerequisite for baclofen to exert epileptogenic activity, since seizures have not occurred in patients receiving intrathecal baclofen for spasticity of solely spinal origin. Antiepileptic medication permitted the continuation of intrathecal baclofen treatment in the three patients.

Adolescent↗
PubMed1993

Effect of the inhibitory phenomenon following magnetic stimulation of cortex on brainstem motor neuron excitability and on the cortical control of brainstem reflexes.

We studied the effect of the inhibitory phenomenon following transcranial magnetic stimulation (TMS) on brainstem motor neuron excitability and on the cortical control of brainstem reflexes in 5 normal subjects. The R1 component of the blink reflex assessed excitability of the facial nucleus during the period of post-TMS inhibition (experiment 1). TMS effect on the cortical control of brainstem reflexes was assessed by delivery of a stimulus that was less than or equal to the threshold for the R1 with the subject relaxed, yet elicited a potentiated reflex during maneuvers requiring cortical input (i.e., voluntary eye-closure and anticipation, experiment 2). In experiment 1, a suprathreshold electric stimulus applied during post-TMS inhibition elicited an R1 response that was preserved in amplitude (mean 476 +/- 44 microV; 123%) compared to control responses not preceded by TMS (mean 386 +/- 31 microV). Conversely, in experiment 2, when the R1 was dependent on cortical drive, the mean R1 amplitude during post-TMS inhibition was only 15% (P < 0.01) and 8% (P < 0.01) of control values obtained during eye-closure and anticipation, respectively. These findings imply that the inhibition following TMS originates rostral to the facial nucleus, at a cortical level.

Adult↗
PubMed1993

Post-traumatic segmental myoclonus associated with bilateral olivary hypertrophy.

We present clinical and magnetic resonance (MR) findings in three patients with segmental myoclonia occurring 11-18 months after severe brainstem injury. Palatal myoclonus and vertical ocular myorhythmia were present in all three patients and synchronous involuntary movements of the upper extremities ("wing beating") in two patients. MR-imaging showed multiple post-traumatic lesions within the dentato-rubro-olivary pathway ("myoclonic triangle"), associated with bilateral enlargement and increased signal intensity of the inferior olives. The signal abnormality was more prominent on proton density weighted images than on T2-weighted images, suggesting underlying pathological changes different from typical gliosis.

Adolescent↗
PubMed1993

Regeneration of sympathetic activities in small bowel transplants.

In order to study the activity of noradrenergic nerve fibres along mesenteric arteries in small-intestinal grafts, the entire jejunoileum was transplanted heterotopically in an isogeneic rat model (group I, n = 12). To assess their influence on graft motility, 9 cm of jejunum were transplanted in an orthotopic position and three bipolar electrodes sutured to the seromuscular layer of the graft (group II, n = 10). Fasting motility was recorded up to postoperative day 42. Animals of group I were sacrificed from day 7 on at weekly intervals and mesenteries were analysed histochemically by fluorescence microscopy. After the 1st and 2nd week, grafts were found to be completely depleted of noradrenaline. At the end of the 3rd week, fluorescence became detectable along graft mesenteric arteries and showed normal intensity from the end of week 4. Migrating myoelectric complexes (MMCs) were present in all animals of group II. The variability of the MMC period (mean 12.6 min; SD 6.2 min) expressed as variation coefficient (median 36.5; 14.6-74) did not change during the observation period. From these findings it is concluded that there are no extrinsic noradrenergic activities in rat small-intestinal transplants for the first 3 postoperative weeks but they do recover there after. Their influence on graft function remains unclear: MMC periodicity, however, was no influenced.

Animals↗
PubMed1992

The silent period in pure sensory neuronopathy.

"Normal" electromyographic silent periods (SPs), produced by electrical stimulation of digital nerves, were recorded in the voluntarily contracting abductor pollicis brevis (APB) muscle of a patient with pure sensory neuronopathy and absent sensory nerve action potentials (SNAPs). Such findings implicate the smaller, slower conducting fibers in the genesis of the cutaneous silent period. These same fibers may be activated during more proximal stimulation to contribute to the latter portions of the mixed nerve silent period.

Action Potentials↗