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Biomedical subjects

M Tegenthoff

Publications and source records attributed to M Tegenthoff.

54 records · Page 3Linked to original sources
PubMed1996

Postexcitatory inhibition after transcranial magnetic single and double brain stimulation in Huntington's disease.

Postexcitatory inhibition (pI) was studied in 13 patients with different clinical forms of Huntington's disease (HD), using a transcranial magnetic single and double stimulation paradigm. We found pathological results of pI in 77% of the HD patients. A significant prolongation of pI could be demonstrated in the group of patients suffering from a classical form of HD. In contrast to these patients, those patients suffering from primary rigid HD variants exhibited a shortening of pI. These results suggest an altered excitability of the motor cortex in HD according to dysfunctions within the motor cortex-basal ganglia loop. Transcranial double stimulation was a more sensitive measure in detecting changes of cortical excitation levels than single stimulation. The interpretation of pI changes in HD has to take the clinical subtype of HD into account.

Adult↗
PubMed1996

Enhancement of inhibitory mechanisms in the motor cortex of patients with cerebellar degeneration: a study with transcranial magnetic brain stimulation.

The excitatory state of the primary motor cortex can be studied by measuring either the postexcitatory inhibition after transcranial magnetic single stimulation (pI-S) or the refractory period with magnetic double stimulation (rP-D). The cerebellum may influence the excitability of the motor cortex by cerebellar inputs and outputs from side loops of transcortical projections. Therefore, we studied pI-S and rP-D in 24 patients with autosomal dominant cerebellar ataxia or idiopathic cerebellar ataxia, who were allocated to one group (Group A) with mild to moderate ataxia (n = 11) and to another group (Group B) with severe ataxia (n = 13). The results were compared with those obtained in 21 normal age-matched control subjects. The central motor conduction time (CMCT) was delayed in approximately half of the patients, demonstrating that the degenerative process, beyond the cerebellum, also affects the pyramidal tract. Mean CMCT was significantly delayed only in patients of Group B. pI-S was prolonged in 10 of our 24 patients; incidence of pathology in pI-S did not differ between the two patient groups. In 5 patients with normal CMCT, pathological pI-S results were found. Mean pI-S was prolonged in the whole patient group and in both subgroups as well. rP-D was prolonged in two patients of Group B only, but mean rP-D was significantly prolonged in the whole patient group. Prolonged postexcitatory inhibition and refractory period may be a consequence of a transient facilitation of cortical inhibitory interneurons, which results in a decreased excitability of primary motor cortex in patients with cerebellar degeneration.

Adult↗
PubMed1996

[Screening study of the thyroid gland within the scope of color-coded duplex ultrasound of brain-supplying arteries].

AIM: We undertook this study to establish whether thyroid diseases influence colour-coded Duplex sonography of cerebral arteries and whether colour-coded Duplex sonography is superior to B-mode sonography in detecting pathological changes of the thyroid. METHOD: In 154 patients the thyroid gland as well as the cerebral arteries were examined by colour-coded Duplex sonography. RESULTS: In 13% of the examined carotid arteries, stenosis or occlusion was detected. Thyroid diseases were found in 21% of the examined patients. In patients with a goitre, carotid arteries were often severely displaced and thyroid vessels exhibited a low resistance waveform, easily to be confused with cerebral arteries. Colour-coded Duplex sonography provides useful information on thyroid vascularisation: however, differentiation between different types of thyroid nodules seems impossible. CONCLUSION: Investigation of the thyroid gland during colour-coded Duplex sonography of neck vessels is easy to perform. It is not time-consuming and may yield useful additional information that may help to explain the patient's complaints.

Adult↗
PubMed1995

Sympathetic skin response in patients with reflex sympathetic dystrophy.

The sympathetic skin response (SSR) originates from synchronized activation of the sweat glands as a response to a volley discharge in efferent sympathetic nerve fibres. The aim of the study was to verify the diagnostic value of SSR in patients with reflex sympathetic dystrophy (RSD). SSR was recorded in 20 normal subjects and in 24 patients with predominantly chronic RSD. In normal subjects inter- and intra-individually different mono-, bi- and triphasic potentials could be recorded without difference of the waveform from side to side. SSR abnormalities were found in 15 patients and correlated with the severity of the disease. In patients with slight dystrophies, SSR was predominantly normal. In intermediate dystrophies, mainly differences of the SSR waveform between sides could be recorded, indicating unilateral sudomotor dysfunction. In severe dystrophies abnormalities of SSR amplitude or latency were found, indicating more serious disturbance of sudomotor activity, possibly due to a lesion of sympathetic fibres. The SSR provides useful information on sudomotor dysfunction in patients with RSD. However, as there is no consensus in the literature for the clinical criteria to diagnose RSD, it is not yet possible to determine the final diagnostic value of SSR for the diagnoses of RSD.

Adult↗
PubMed1995

Changes of cortical motor area size during immobilization.

Changes of motor cortex organization after lesions in the nervous system can be demonstrated by mapping the motor cortex with transcranial magnetic stimulation. We studied cortical plasticity in 22 patients who had a unilateral immobilization of the ankle joint without peripheral nerve lesion. The motor cortex area of the inactivated tibial anterior muscle diminished compared to the unaffected leg without changes in spinal excitability or motor threshold. The area reduction was correlated to the duration of immobilization. It could be quickly reversed by voluntary muscle contraction. This indicates a functional (and not morphological) origin of the phenomenon.

Adult↗
PubMed1995

A missense point mutation (Ser515Phe) in the adrenoleukodystrophy gene in a family with adrenomyeloneuropathy: a clinical, biochemical, and genetic study.

A 36 year old male patient with adrenomyeloneuropathy (AMN) developed progressive spastic paraparesis and sensory ataxia from the age of 18. Biochemical studies showed increased plasma concentrations of saturated very long chain fatty acids (VLCFAs), subclinical evidence of adrenal insufficiency, and primary hypogonadism. Three female family members had increased plasma concentrations of VLCFAs, suggesting carrier status of adrenoleukodystrophy (ALD). Molecular genetic analysis detected a missense point mutation (C1930T) in exon 6 within the ALD gene, which predicts substitution of an amino acid (Ser515Phe) that is conserved between the deduced amino acid sequence of the peroxisomal membrane protein PMP70 and ALD protein. Detection of this point mutation allows diagnosis of ALD or AMN, identification of heterozygotes, and prenatal diagnosis of ALD.

Adrenoleukodystrophy↗
PubMed1994

[Assessment of central nervous system functional disorders in severely burned patients by auditory evoked brain stem potentials].

The recording of brainstem auditory evoked potentials (BAEP) in severely burned patients can be used for judgement of brainstem function independent of consciousness and CNS-effective drugs. The frequency of central-nervous system complications due to burn injuries is between 7 and 30%. Using BAEP-recordings, we found objective neurophysiological parameters of central-nervous dysfunction in 12 of 25 severely burned patients (48%). Specific BAEP-parameters for burn injuries could not be detected. Specifically, very different time courses of BAEP-changes were found. In two patients, who died after severe burn injury, typical neurophysiological patterns of progressive cerebral pressure were observed. The measurement of BAEP is a useful diagnostic tool in detecting central-nervous dysfunction after burn injuries, especially for monitoring in non-cooperative patients.

Adolescent↗
PubMed1994

Follow-up investigations of peripheral facial palsy by transcranial magnetic stimulation.

Twenty-three patients (10 men, 13 women; age: from 23 to 81 years, mean 52 years) with Bell's palsy were investigated by magneto-electrical stimulation in order to evaluate the usefulness of this method for prognostication. At each examination the facial nerve was electrically stimulated, and an orbicularis-oculi-reflex was elicited. Follow-up investigations were possible in 13 patients. All patients showed pathological long- and short-latency responses at the first examination. The blink reflex examination revealed a pathological result in all cases. The responses to electrical stimulation were pathological only in 35%. The follow-up examinations revealed that the analysis of the short-latency response did not give a prognostic information. In contrast, maintained elicitation of the long-latency response pointed to a favourable prognosis. In follow-up investigations, the increase of amplitude and the decrease of latency of the long-latency response correlated with a complete recovery, while the decrease of amplitude and the increase of latency correlated with a partial recovery. The improvement of the responses in magnetic stimulation preceded the clinical improvement. By using magnetic stimulation, an early registration and evaluation of the course of Bell's palsy are possible.

Action Potentials↗
PubMed1994

[Transcranial magnetic stimulation in diagnosis of trigeminal neuralgia].

Patients with trigeminal neuralgia are usually investigated by elicitation of the orbicularis oculi reflex and trigeminal evoked potentials. These neurophysiological methods do not allow direct judgement of the trigeminal nerve. By transcranial magnetic stimulation, however, non-invasive investigation of the efferent part of the trigeminal nerve is possible. 10 patients (4 men, 6 women, aged from 43 to 73 years) with trigeminal neuralgia affecting the second or third division were examined. In all patients bilateral long-latency responses after stimulation of the tractus corticonuclearis and short-latency responses after stimulation of the proximal part of the trigeminal nerve were registered. 8 patients showed normal short- and long-latency responses, while in one other patient the long-latency responses were delayed on both sides. The remaining patient revealed a significant difference of amplitude compared to the contralateral long-latency response. This patient had a pontine lesion as shown by blink reflex and a pathological trigeminal evoked potential. In both these latter patients multiple sclerosis was diagnosed. Use of transcranial magnetic stimulation may thus prove helpful in the differential diagnosis of neurological disorders presenting with trigeminal neuralgia.

Adult↗
PubMed1993

[Acute effect of metoclopramide on esophagus motility in diabetes mellitus].

The acute effect of metoclopramide on oesophageal motility was investigated prospectively in 33 consecutive patients (20 men and 13 women; mean age 60.5 +/- 12.6 years) with type I (n = 8) or type II (n = 25) diabetes. 15 patients had a peripheral sensory-motor polyneuropathy only and three just an autonomic cardial neuropathy. Both lesions were present in ten, none in five. No patient had oesophago-gastroduodenal lesions. Sphincter pressure, relaxation time, contraction amplitude and propulsion velocity of bolus-induced oesophageal peristalsis were measured manometrically after intravenous administration of 10 mg metoclopramide. Resting pressure in the lower oesophageal sphincter rose significantly by 26.7%, contraction amplitude in the tubular portion of the oesophagus by more than 30%, and propulsion velocity by more than 20% (P for each < 0.05). At the same time the amount of segmental and aperistaltic oesophageal contractions regressed significantly. The effect of metoclopramide was demonstrated regardless of the type of diabetes, duration of diabetes and any manifestation of autonomic cardial or peripheral sensory-motor neuropathy.

Adult↗
PubMed1993

[Transcranial magnetic stimulation in perioperative damage to the facial nerve].

5 patients (3 men, 2 women, aged from 28 to 51 years) with unilateral facial palsy after surgery of a cerebellopontine angle tumour have been investigated by transcranial magnetic stimulation. The purpose was to evaluate the prognostic aspects of this method, which was compared with the electrical stimulation of the facial nerve and the elicitation of an orbicularis-oculi reflex. The components of the blink reflex were absent in all cases. In 3 patients electrical stimulation was possible (compound muscle action potentials were delayed). With transcranial magnetic stimulation ipsilateral short-latency and contralateral long-latency responses (stimulation of the cortex) were elicited and registered from the M. mentalis as well as 3 times from the M. orbicularis oculi. The short-latency response revealed no prognostic aspects. Despite the missing response, a recovery was possible. Long-latency responses could be evoked in all patients. The extent of delay in latency was strongly correlated with clinical improvement of the paresis. Interestingly, this correlation could also be observed in the single rami of the facial nerve when two muscles were investigated in a patient. Transcranial magnetic stimulation is an important improvement in electrophysiological diagnosis of perioperative lesion of facial nerve to prove continuity of the nerve and to evaluate the clinical course.

Adult↗
PubMed1992

Esophageal dysfunction in diabetes mellitus: is there a relation to clinical manifestation of neuropathy?

In a prospective study, we evaluated 33 diabetic patients [type I (n = 8) and type II (n = 25)]. Esophageal motor functions were examined by registering clinical symptoms and by performing esophageal manometry. We also investigated peripheral and autonomic neuropathy. In diabetics, the lower and upper esophageal sphincter pressure and amplitudes of peristaltic waves were reduced. Compared with controls (n = 30), in diabetics the esophageal peristaltic velocity was reduced significantly, and the duration of contractions were decreased as well. Multipeaked waves were uncommon in diabetics, while non-propulsive contractions were seen more often. No correlation was found between esophageal dysfunction and peripheral or autonomic neuropathy. Some 60% of diabetics reported esophageal symptoms; however, no relationship between these symptoms and the extent of dysfunction in esophageal motility was found.

Adult↗
PubMed1992

[Transcranial magnetic stimulation of patients with a single epileptic seizure].

Transcranial magnetic stimulation (TMS) was performed in 21 patients who had had loss of consciousness of unknown origin, in order to find out whether TMS could help in finding the cause of unconsciousness and to estimate the risk of provoking a seizure in patients who had single fits in the past. Furthermore, EEG recordings with hyperventilation, photostimulation, 24-hour EEG and sleep-deprivation EEG's were carried out as well as CCT or NMR investigation. In 15 patients the loss of consciousness was judged to be due to an epileptic seizure. None of the 21 patients had epileptic potentials in EEG recordings or showed an epileptic seizure during or after TMS, hyperventilation or photostimulation. One patient developed spike-wave activity in the sleep-deprivation EEG, another in the 24-hour EEG. On the basis of our results and previous reports, TMS does not seem to be helpful in the diagnosis of loss of consciousness of unknown origin. However, TMS can be used more liberally than hitherto in the study of motor pathways, in cases with a history of single epileptic seizures.

Adult↗
PubMed1992

[Transcranial magnetic stimulation in the cranial nerve region in cranio-cerebral injuries].

By means of transcranial magnetic stimulation bilateral compound muscle action potentials of long latency and ipsilateral potentials of short latency can be obtained in muscles supplied by cranial nerves. In this study motor evoked potentials were recorded from the mentalis muscle of 14 patients with traumatic brain lesions. These results were compared with clinical and radiological as well as other neurophysiological examinations. In spite of the absence of paralysis in muscles supplied by the facial nerve, 9 patients showed pathological long-latency responses, which correlated with the localisation of the paralysis of the limbs. In contrast to this, the degree of pathological latencies of motor evoked potentials did not correspond with the degree of paresis in different patients. A prediction concerning the clinical outcome could not be made by the results of motor evoked potentials. The clinical data showed a poor correlation with the structural brain lesions seen in the CT-scan and the results of EEG, BAEP and orbicularis oculi reflex examination. In conclusion, transcranial magnetic stimulation of cranial nerves proved to be a sensitive method for the evaluation of degree and localization of motor deficits following traumatic brain lesion and seems to be superior to the other examinations compared.

Adult↗
PubMed1991

Multifactorial genesis of neuroradiological "leucoencephalopathies.".

Three cases of neuroradiologically diagnosed "leucoencephalopathy" are reported. Histopathological examination disclosed Binswanger's encephalopathy in Case 1, congophilic angiopathy with secondary leucoencephalopathy in Case 2, and HIV encephalopathy with secondary white matter changes in Case 3. These three cases demonstrate the unspecificity of neuroradiological findings in "leucoencephalopathy".

AIDS Dementia Complex↗
PubMedDate not supplied

Carotid and vertebral artery injury following severe head or cervical spine trauma.

In order to determine the frequency of neck vessel injuries, Doppler investigations were performed in 60 patients following either severe head injury (n = 29), cervical spine injury (n = 26), or combined head and cervical spine injury (n = 5). The majority of patients were referred to our hospital for early rehabilitation; before admission Doppler investigations had been performed in only 2 patients. Clinically, 3 patients sustained severe cerebral ischemia due to neck vessel trauma: 1 patient with left-sided ICA dissection after head trauma revealed Doppler abnormalities only in the early phase of the disease; the second patient demonstrated persistent Doppler abnormalities due to traumatic right-sided ICA and VA occlusion. The third patient sustained a fatal vertebral and basilar artery thrombosis following cervical spine injury. In 57 patients without clinical signs suspicious of neck vessel trauma, sonography revealed abnormalities in 3 patients (11%) with severe head injury and in 6 patients (20%) with cervical spine or combined head and spine injury, in both groups mainly related to the vertebrobasilar system. Neck vessel injury is probably an underdiagnosed complication of severe head or cervical spine trauma. Although interpretation of Doppler findings may be difficult, particularly in the vertebrobasilar system, Doppler investigations can be recommended as a screening method to exclude neck vessel injuries.

Adolescent↗