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H C Hopf

Publications and source records attributed to H C Hopf.

At least 55 records · Page 3Linked to original sources
PubMed1999

[Spontaneous intracranial hypotension syndrome. Clinical, neuroradiological and cerebrospinal fluid findings].

We report 11 patients with orthostatic headache due to spontaneous intracranial hypotension. Nausea (3 patients) and abducens palsy (2 patients) were the main additional symptoms. Ten patients had CSF pleocytosis (6 to 43 white cells/microliter) and/or increased protein (581 to 1668 mg/l). CT and/or MRI documented bifrontal accentuated subdural hygromas and hematomas in 5 patients. MRI also documented diffuse meningeal gadolinium enhancement in all 4 patients examined, and descent of the brain in one. Cisternography was done in 9 patients and revealed a decreased or absent activity over the convexities and early detection of the tracer in the bladder in all, and a CSF leak at the cervicothoracal junction in 2 patients. Most patients improved with bed rest, increased fluid intake (oral or intravenous), steroids, and/or epidural blood patch. Subdural hematomas increased in 2 patients and have to be drained. Spontaneous intracranial hypotension is due to a CSF leak followed by decreased CSF volume and hydrostatic CSF pressure changes. The locations of the leaks are mainly cervical or at the cervicothoracal junction. MRI always documents diffuse meningeal gadolinium enhancement. Treatment of choice is an epidural blood patch. Surgical treatment may be needed in patients with subdural hematomas or meningeal diverticula. Prognosis is typically good, but subdural hematomas may occasionally lead to an increased intracranial pressure.

Adult↗
PubMed1999

Abolished laser-evoked potentials and normal blink reflex in midlateral medullary infarction.

We investigated two patients presenting with the rare finding of almost isolated hemianalgesia with a sensory level on the contralateral side sparing the face. Clinical findings, electrophysiological studies (absent laser-evoked pain-related somatosensory potentials, normal electrically evoked somatosensory potentials, magnetically evoked potentials, and blink reflexes), and magnetic resonance imaging showed the ventrolateral medullar tegmentum containing the spinothalamic tract to be affected by lacunar infarction. The blink reflex R2 component was unimpaired in both patients.

Adult↗
PubMed1999

Ipsilateral facial weakness in upper medullary infarction-supranuclear or infranuclear origin?

We describe two patients with upper medullary infarctions showing ipsilateral facial weakness and relative sparing of the upper facial muscles. Electrophysiological follow-up using transcranial magnetic stimulation of the motor cortex in combination with stimulation of the peripheral facial nerve disclosed a supranuclear (corticofacial) tract lesion in one patient and a partial nuclear/infranuclear intra-axial facial nerve lesion in another.

Aged↗
PubMed1999

Latency and amplitude variability in serial median nerve SEP recordings.

OBJECTIVES: Intra-individual variability of SEP parameters was investigated by serial SEP recordings. METHODS: Median nerve SEP of 53 normal subjects (mean age 25.5+/-2.7 years) were evaluated. Recordings were repeated 1 week, 2 weeks, and 6 months after the initial recording. RESULTS: Mean values of latencies from right median nerve stimulation were slightly longer (+0.1 ms) as compared to the left. The intra-individual (within stimulation side) variance did not depend on the time interval between recordings. The total within-stimulation-side variance of latencies was 0.056 ms2 for N20 (C3/4' vs. Fz), 0.070 ms2 for N13 (C7 vs. Fz), 0.048 ms2 for N10 (Erb's point vs. Fz), 0.111 ms2 for P9 (C3/4' vs. contralateral forearm), and 0.148 ms2 for P14 (C3/4' vs. contralateral forearm), and was about 3 times smaller than between-side variability with regard to cortical or spinal potentials. Upper limits for latency differences and lower limits for amplitude ratios in repeated recordings, as well as upper and lower limits for between-side latency differences and amplitude ratios were calculated, using F distributions with worst-case assumptions for degrees of freedom and error probability P = 0.05. Upper limits of within-stimulation-side latency differences were 0.55 ms for N20, 0.62 ms for N13, 0.51 ms for N10, 0.78 ms for P9, and 0.90 ms for P14, and corresponding lower limits of amplitude ratios were 0.69, 0.62, 0.66, 0.45, and 0.50, respectively. CONCLUSIONS: Our results demonstrate a small systematic, and a larger random difference between right and left side stimulation, one arising from the peripheral, and the other one from the central pathway proximal to the source of N10.

Adolescent↗
PubMed1999

Increased risk of sensory neuropathy in workers with chloracne after exposure to 2,3,7,8-polychlorinated dioxins and furans.

OBJECTIVE: The existence of a peripheral neuropathy after exposure to polychlorinated dioxins (PCDD) is still discussed, as studies concerning dioxin effects on the peripheral nervous system are rare and contradictory. MATERIAL AND METHODS: Clinical and neurophysiological examinations (motor conduction velocity of the peroneal nerve, sensory conduction velocities of the sural and ulnar nerves) were made in 156 dioxin exposed workers (42 with, 114 without cloracne) from one pesticide producing plant. Because of known risk factors for peripheral neuropathy, 7 workers with and 28 without cloracne were excluded from further analysis. RESULTS: Workers with chloracne had a significantly higher exposure against PCDD as documented by back calculated lipid levels. They complained significantly more often of sexual impotence (28.6% compared to 5.8% of workers without chloracne, P<0.001), had significantly more frequent clinical signs of a sensory neuropathy (= abnormal sensory findings plus deep tendon reflex abnormalities) restricted to the legs (17.1% compared to 1.2%, P<0.001), had significantly more frequent > or =2 neurophysiologic abnormalities (34.3% compared to 14.0%, P<0.025), and had significantly lower mean amplitudes of the motor compound muscle potential of the peroneal nerve. CONCLUSION: PCDD has a mild toxic effect on the peripheral nervous system manifesting as mild sensory neuropathy of the legs in a minority of the most severely exposed persons.

Acne Vulgaris↗
PubMed1999

Pontine lesions mimicking acute peripheral vestibulopathy.

OBJECTIVES: Clinical signs of acute peripheral vestibulopathy (APV) were repeatedly reported with pontine lesions. The clinical relevance of such a mechanism is not known, as most studies were biased by patients with additional clinical signs ofbrainstem dysfunction. METHODS: Masseter reflex (MassR), blink reflex (BlinkR), brainstem auditory evoked potentials (BAEPs), and DC electro-oculography (EOG) were tested in 232 consecutive patients with clinical signs of unilateral APV. RESULTS: Forty five of the 232 patients (19.4%) had at least one electrophysiological abnormality suggesting pontine dysfunction mainly due to possible vertebrobasilar ischaemia (22 patients) and multiple sclerosis (eight patients). MassR abnormalities were seen in 24 patients, and EOG abnormalities of saccades and following eye movements occurred in 22 patients. Three patients had BlinkR-R1 abnormalities, and one had delayed BAEP waves IV and V. Clinical improvement was almost always (32 of 34 re-examined patients) associated with improvement or normalisation of at least one electrophysiological abnormality. Brain MRI was done in 25 of the 44 patients and confirmed pontine lesions in six (two infarcts, three inflammations, one tumour). CONCLUSIONS: Pontine dysfunction was suggested in 45 of 232 consecutive patients with clinical signs of APV on the basis of abnormal electrophysiological findings, and was mainly attributed to brainstem ischaemia and multiple sclerosis. The frequency of pontine lesions mimicking APV is underestimated if based on MRI established lesions only.

Acoustic Stimulation↗
PubMed1999

Isolated dysarthria due to extracerebellar lacunar stroke: a central monoparesis of the tongue.

OBJECTIVES: The pathophysiology of dysarthria can preferentially be studied in patients with the rare lacunar stroke syndrome of "isolated dysarthria". METHODS: A single study was carried out on seven consecutive patients with sudden onset of isolated dysarthria due to single ischaemic lesion. The localisation of the lesion was identified using MRI. The corticolingual, cortico-orofacial, and corticospinal tract functions were investigated using transcranial magnetic stimulation. Corticopontocerebellar tract function was assessed using 99mTc hexamethylpropylene amine oxime-single photon emission computerised tomography (HMPAO-SPECT) in six patients. Sensory functions were evaluated clinically and by somatosensory evoked potentials. RESULTS: Brain MRI showed the lesions to be located in the corona radiata (n=4) and the internal capsule (n=2). No morphological lesion was identified in one patient. Corticolingual tract function was impaired in all patients. In four patients with additional cortico-orofacial tract dysfunction, dysarthria did not differ from that in patients with isolated corticolingual tract dysfunction. Corticospinal tract functions were normal in all patients. HMPAO-SPECT showed no cerebellar diaschisis, suggesting unimpaired corticopontocerebellar tract function. Sensory functions were not affected. CONCLUSION: Interruption of the corticolingual pathways to the tongue is crucial in the pathogenesis of isolated dysarthria after extracerebellar lacunar stroke.

Cerebellum↗
PubMed1999

Blink reflex R2 changes and localisation of lesions in the lower brainstem (Wallenberg's syndrome): an electrophysiological and MRI study.

OBJECTIVES: Pathways of late blink reflexes are detected by high resolution MRI. Electronically matched stroke lesions superimposed to an anatomical atlas show the suspected course. METHODS: Fifteen patients with infarction of the lower brainstem, MRI lesions and electrically elicited blink reflexes were examined. The involved structures in patients with R2 and R2c blink reflex changes were identified by biplane high resolution MRI with individual slices matched to an anatomical atlas at 10 different levels using digital postprocessing methods. RESULTS: The blink reflexes were normal in five of 15 patients (33%) and showed loss or delay of R2 and R2c to stimulation ipsilaterally to lesion (R2-i and R2c-i) in eight (53%). Loss or delay of R2-i/R2c-i was seen in lesions covering the entire trigeminal spinal tract and nucleus (TSTN) at at least one level. These infarctions were located more dorsally within the medulla. Patients with normal blink reflexes showed lesions sparing or involving the TSTN only partially. They more often had incomplete Wallenberg's syndromes and MRI lesions were located more ventrally. CONCLUSIONS: Using digital postprocessing MRI methods it was possible to identify central pathways of late blink reflex in patients with Wallenberg's syndrome. This method is suggested as a new approach to identify incompletely understood functional structures of the brainstem.

Aged↗
PubMed1999

[Continuing medical education (CME) in neurology. Concept of the German Society of Neurology (DGN) and the Neurology Section of the Professional League of German Neurologic Medicine (BVDN)].

Continuous medical education in Neurology (CME-Neurology) has been promoted in a concept organized by both the German society of neurology, German association for occupational interests of neurologists and psychiatrists). CME-Neurology has been started in January 1999 and is closely adapted to the CME guidelines of neurology section of UEMS and EFNS. The program shall serve to the maintenance and upgrading of knowledge skills and competence of postgraduate training in neurology.

Education, Medical, Continuing↗
PubMed1998

Differentiation of recent and old cerebral infarcts by diffusion-weighted MRI.

We performed MRI, including diffusion-weighted imaging, in 15 patients with recurrent strokes with acute ischaemia and at least one old lesion according to the clinical history and/or CT. Routine MRI showed similar signal intensity changes in both situations. Diffusion-weighted images, however, were positive in all acute or subacute infarcts. The high signal of acutely disturbed diffusion due to intracellular oedema could also be identified in small brain stem lesions. Spatial resolution was increased by applying separate gradients in each axis instead of creating anisotropy-independent trace images.

Adult↗
PubMed1998

Electrophysiological brain stem investigations in idiopathic narcolepsy.

Narcolepsy is associated with various rapid eye movement (REM) sleep abnormalities. Distinct brain stem areas seem to play a prominent role in REM sleep regulation. Recent magnetic resonance imaging (MRI) studies have led to conflicting findings concerning the presence of structural brain stem lesions in patients with idiopathic narcoleptic syndrome. However, multimodal electrophysiological brain stem investigations may reveal functional brain stem abnormalities even in the absence of MRI abnormality. Therefore we investigated brain stem function in 12 idiopathic narcoleptic patients by systematically studying tegmental brain stem pathways. All of the patients met the diagnostic criteria of the International Classification of Sleep Disorders, with typical changes in polysomnography and the multiple sleep latency test. Electrophysiological investigations comprised masseter reflex, blink reflex, masseter inhibitory reflex, early auditory evoked potentials and electrooculography with vestibular testing. In no patient were electrophysiological brain stem abnormalities observed. Our findings do not support the existence of a relevant brain stem lesion in narcoleptic patients with normal neurological status.

Adult↗
PubMed1998

Evoked isometric muscle contractions in myopathies: analysis of pathophysiological properties by different stimulus patterns.

Isometric twitches of the adductor pollicis muscle following ulnar nerve stimulation were investigated in healthy subjects (n = 35) and patients with different types of myopathies (myotonic dystrophy, n = 19; limb girdle muscular dystrophy, n = 10; metabolic myopathy, n = 6). The changes within the rising part (i.e. within the contraction time, CT) of the isometric twitches after single stimuli were similar in myotonic and limb girdle dystrophies: the first part of CT, which lasts until the maximal contraction rate is achieved, was shortened, whereas the following second part of CT, which lasts until the maximal twitch force is achieved, was normal. In metabolic myopathies the first part was normal, whereas the second part was prolonged. The relaxation was prolonged in all types of myopathies, particularly in metabolic myopathies. Using double stimuli with short interstimulus intervals (ISI), the absolute refractory period of the muscle contraction (healthy subjects: 1.35 +/- 0.16 ms) was shortened in patients with myotonic dystrophy (1.02 +/- 0.11 ms). In the other types of myopathies, the absolute refractory period was only shortened provided that the single twitch force was clearly reduced. A similar dependence on a reduced single twitch force was also found with regard to the maximal force development with two stimuli and the corresponding ISI: the force contributed by a second stimulus was pathologically enhanced if the single twitch force was clearly reduced. The ISI related to the maximal force with two stimuli was shifted towards very short values (healthy subjects: 10.5 ms, myotonic dystrophy: 4.6 ms, limb girdle dystrophies: 5.0 ms). Our results can be attributed to altered kinetics of calcium release and uptake by the sarcoplasmic reticulum in myopathies.

Adolescent↗
PubMed1998

Corticobulbar tract involvement in amyotrophic lateral sclerosis. A transcranial magnetic stimulation study.

We investigated corticobulbar tract function by recording from the tongue and orofacial muscles and using transcranial magnetic stimulation (TMS) in 30 patients with amyotrophic lateral sclerosis (ALS) in order to improve the diagnostic yield in the detection of subclinical upper motor neuron (UMN) dysfunction. A UMN lesion was assumed when the peripheral conduction time and amplitude of the M-wave were within normal range and either the response to cortical stimulation was absent, or the central conduction time was delayed (> mean + 2.5 SD). Only two patients showed clinical evidence of UMN involvement in the cranial nerves, while TMS demonstrated corticobulbar tract dysfunction in the orofacial muscles in 17 patients (57%) and to the tongue in 15 patients (50%). Following recording at both sites, corticobulbar tract dysfunction was confirmed in 21 patients (70%). Twelve out of 13 patients with bulbar symptoms had evidence of additional subclinical corticobulbar tract involvement using TMS. In seven out of 15 patients with isolated limb involvement, subclinical corticobulbar tract dysfunction was demonstrated. Our results indicate the presence of early and, in most cases, subclinical corticobulbar tract involvement in the pathways to the orofacial muscles and tongue in ALS.

Adult↗