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J Marx

Publications and source records attributed to J Marx.

At least 55 records · Page 3Linked to original sources
PubMed2000

Masseter reflex latencies and amplitudes are not influenced by supratentorial and cerebellar lesions.

The aim of this study was to investigate possible influences of suprasegmental lesions on the masseter reflex. The masseter reflex was elicited in 54 patients with supratentorial (37 patients) or cerebellar (17 patients) lesions 3-11 days after the acute onset of clinical disease. Patients showing lesions within the pons and midbrain on thin-slice magnetic resonance imaging were excluded from evaluation. The testing procedure included an additional facilitating maneuver (opening and closing the jaw before tapping). Masseter reflex latencies, interside differences, and amplitudes were within the normal range in all patients. Latencies were not different with and without the facilitating maneuver. Amplitudes were significantly higher with the maneuver, but interside differences of amplitudes were unchanged. Masseter reflex abnormality can be taken as a reliable measure of direct involvement of the reflex arc.

Adult↗
PubMed1999

Long-term effects of transcranial magnetic stimulation on hippocampal reactivity to afferent stimulation.

Transcranial magnetic stimulation (TMS) has become a promising treatment of affective disorders in humans, yet the neuronal basis of its long-lasting effects in the brain is still unknown. We studied acute and lasting effects of TMS on reactivity of the rat hippocampus to stimulation of the perforant path. Application of TMS to the brain of the anesthetized rat caused a dose-dependent transient increase in population spike (PS) response of the dentate gyrus to perforant path stimulation. In addition, TMS caused a marked decrease in inhibition and an increase in paired-pulse potentiation of reactivity to stimulation of the perforant path. Also, TMS suppressed the ability of fenfluramine (FFA), a serotonin releaser, to potentiate PS response to perforant path stimulation. Chronic TMS did not affect single population spikes but caused an increase in paired-pulse potentiation, which was still evident 3 weeks after the last of seven daily TMS treatments. After chronic TMS, FFA was ineffective in enhancing reactivity to perforant path stimulation, probably because it lost the ability to release serotonin. In addition, the beta adrenergic receptor agonist isoproterenol, which caused an increase in PS in the control rats, failed to do so in the TMS-treated rats. These results indicate that TMS produces a long-term reduction in efficacy of central modulatory systems.

Afferent Pathways↗
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

Leptomeningeal carcinomatosis and cranial nerve palsy as presenting symptoms of a clinically inapparent gallbladder carcinoma.

We present an occult metastatic signet-ring cell gallbladder carcinoma in a 78-year-old woman, who complained of recurrent headaches, dysarthria, and paresis of the tongue. Cranial imaging showed contrast enhancement of the basal leptomeninges, and the cerebrospinal fluid displayed clusters of adenocarcinoma cells proposed as leptomeningeal carcinomatosis of the breast, lung or gut. However, postmortem examination revealed the gallbladder as the site of the primary carcinoma with focal signet-ring cell differentiation. In patients with progressive neurologic deterioration due to leptomeningeal carcinomatosis, adenocarcinomas from the gastrointestinal and hepatic systems should be considered. It is likely that signet-ring cell carcinomas display an increased affinity to leptomeningeal spread.

Aged↗
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

Who cares? Grandparent/grandchild households.

Based on data from the 1988 National Health Interview Survey and the Child Health Supplement, we compared the health of women 40 years of age and over living four family structures: alone, solely raising grandchildren, married with spouse only, and married with spouse and grandchildren. We found that, in general, women solely raising grandchildren have poorer health compared to women of a similar age living in other family structures and considerably worse health than women with spouses raising grandchildren.

Adult↗
PubMed1998

Isolated voluntary facial paresis due to pontine ischemia.

We describe a patient with isolated voluntary facial paresis due to a unilateral lacunar lesion in the contralateral mediodorsal middle base of the pons. Transcranial magnetic stimulation confirmed the involvement of supranuclear corticofacial tract fibers and sparing of the corticolingual and corticospinal connections. This observation demonstrates that the fibers conveying voluntary orofacial activation descend mediodorsally at the level of the middle pons and that the fibers conveying emotional activation may be assumed to converge below this level.

Aged↗