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Biomedical subjects

M Feinsod

Publications and source records attributed to M Feinsod.

At least 37 records · Page 2Linked to original sources
PubMed1998

Profuse hemorrhage from cerebral vessels in tangential missile injuries.

Tangential missile injuries are recognized as a cause of cerebral damage by in driven bone fragments, parenchymal lacerations and intracerebral haematomas. Severe blood loss from this type of injury was not reported. Four patients are described in whom high kinetic energy missiles caused severe tangential craniocerebral injuries. Their condition was aggravated by life threatening haemorrhage. The bleeding vessels were cerebral arteries or major veins entrapped in the fracture line and bleeding extracranially. This blood loss cannot be controlled by dressing and salvage could be achieved only by immediate resuscitation, vigorous fluid replacement and very rapid evacuation to a neurosurgical center.

Adult↗
PubMed1998

Altered excitability of the motor cortex after minor head injury revealed by transcranial magnetic stimulation.

This study attempts to find out whether the motor evoked potential (MEP) elicited by single pulse and slow-rate (1 Hz) repetitive transcranial magnetic stimulation (TMS) can disclose concealed subclinical impairments in the cerebral motor system of patients with minor head injury. The motor response to single pulse TMS (STMS) of the patient group was characterized by significantly higher threshold compared with that of the control group. The central motor conduction time, as well as the peripheral conduction time were normal in all patients pointing to cortical impairment. Two main patterns of MEP changes in response to repetitive TMS (RTMS) were observed in the patient group. A.--progressive decrease of the MEP amplitude throughout the stimulation session to a near complete abolition. B.--irregularity of the amplitude and the waveform of the MEP in a chaotic form. The MEP latency remained stable during the whole stimulation session. The MEP abnormalities recovered gradually over the period of a few months. The higher threshold of the motor response to STMS and the abnormal patterns of the MEP to RTMS seem to reflect transient impairment of cortical excitability or "cortical fatigue" in patients who sustained minor head injures. Further study is needed to evaluated the extent and the pathophysiological mechanisms of the central nervous system fatigue phenomenon following head injury.

Adult↗
PubMed1998

Indocyanine-green videoangiography of drusen as a possible predictive indicator of exudative maculopathy.

OBJECTIVE: Recent studies have shown that indocyanine-green videoangiography (ICG-V) is useful to image occult choroidal neovascularization. The authors studied the ICG-V findings in fellow drusen eyes of patients with unilateral exudative age-related macular degeneration (AMD). The authors also studied the occurrence of exudative changes to determine whether ICG-V is useful in predicting future exudative changes in these eyes with only drusen. DESIGN: Cohort study. PARTICIPANTS: The authors studied 432 consecutive patients diagnosed with unilateral exudative AMD in whom the fellow eye had only drusen by clinical fundus examination and fluorescein angiography. All of these eyes had ICG-V performed. Follow-up data were obtained in all eyes with abnormal indocyanine-green (ICG) angiograms and randomly sampled ICG angiograms of normal eyes. MAIN OUTCOME MEASURES: The initial ICG findings were classified as showing normal or abnormal hyperfluorescence. Abnormal hyperfluorescence eyes were subdivided into focal spots (focal areas of hyperfluorescence < 1 disc area in size) and plaques (areas of hyperfluorescence > 1 disc area). The development of exudative changes in eyes with normal and abnormal hyperfluorescence was compared. RESULTS: Of the 432 fellow eyes, 386 (89%) eyes with drusen had a normal ICG-V study, whereas 46 (10 focal spots and 36 plaques) (11%) eyes had an abnormal ICG-V. Exudative changes occurred in 6 (10%) of 58 normal ICG eyes and 9 (24%) of 38 eyes with abnormal ICG findings during a mean follow-up period of 21.7 months. The difference between drusen eyes with normal ICG angiograms and those with plaques on ICG-V regarding future exudative changes (10% vs. 27%, respectively) was statistically significant (P = 0.038). CONCLUSIONS: Abnormal ICG findings were found in 11% of eyes with clinically and fluorescein angiographically nonsuspicious drusen. The subgroup of patients with plaques on ICG-V had a higher chance of having exudative changes develop. Indocyanine-green videoangiography may be a predictive indicator of future exudative changes in eyes with drusen. A much larger prospective study seems justified.

Aged↗
PubMed1998

Transcranial Doppler in vertebrobasilar vasospasm after subarachnoid hemorrhage.

OBJECTIVE: The primary objective of this study was to assess the incidence of vertebrobasilar vasospasm after subarachnoid hemorrhage (SAH) by means of transcranial Doppler ultrasonography and to evaluate the clinical significance of this phenomenon. The secondary objective was to analyze the different factors influencing the development, the severity, and the duration of vertebrobasilar vasospasm. METHODS: Fifty-seven patients with traumatic SAH and 44 patients with spontaneous SAH were evaluated and monitored by means of transcranial Doppler ultrasonography. Vasospasm of the anterior and middle cerebral arteries was defined by mean flow velocities (FVs) exceeding 120 cm per second and at least three times the FV of the internal carotid artery. Vasospasm of the basilar and vertebral arteries was defined by a mean FV exceeding 60 cm per second. RESULTS: Vasospasm of the anterior or middle cerebral arteries was found in 27 patients and was associated with vertebrobasilar spasm in 20 patients. FVs in anterior circulation vessels were neither related to the cause of the SAH nor did they correlate with the outcome. Forty-six patients (45.5%) had FVs exceeding 60 cm per second and 25 (24.8%) had FVs exceeding 85 cm per second. In 10 of these patients, direct or computed tomographic angiography showed arterial narrowing involving the vertebrobasilar system, whereas in 21 more patients, computed tomography disclosed a cerebral infarction involving the vertebrobasilar vascular territory. Vertebral artery FVs in this group were twice that of the ipsilateral carotid artery. Vertebrobasilar vasospasm was significantly more frequent after head injury, although it was not related to the type of intracranial lesion or the Glasgow Coma Scale score at admission. It did correlate, however, with outcome (P < 0.0001) and with the intensity of SAH (P < 0.0001). Delayed neurological deterioration occurred in 14 patients and was significantly more frequent in patients with basilar artery FVs above 85 cm per second (P < 0.001). Prognosis, however, could not be reliably predicted by FVs in the basilar artery, even when an FV of 110 cm per second was chosen for prediction criterion. CONCLUSION: These results suggest that vertebrobasilar vasospasm is more common than previously thought, especially in association with head injury, with which it may significantly contribute to brain stem ischemic lesions and therefore justify specific therapeutic measures.

Adolescent↗
PubMed1998

Preliminary evidence for a beneficial effect of low-frequency, repetitive transcranial magnetic stimulation in patients with major depression and schizophrenia.

OBJECTIVE: This study was designed to evaluate the potential efficacy of repetitive transcranial magnetic stimulation (rTMS) at low-frequency in patients with major depression and schizophrenia. EXPERIMENTAL DESIGN: We investigated the therapeutic effect of a course of 10 rTMS sessions in 14 subjects with major depression (MD) and 10 with schizophrenia. PRINCIPAL OBSERVATIONS: Seven of the depressed patients reported significant improvement in depressive symptomatology, and seven of the schizophrenic subjects reported amelioration of anxiety and restlessness. CONCLUSIONS: These preliminary results suggest that low-frequency rTMS may be beneficial mainly in MD and to some extent in schizophrenia, and support the need for controlled studies to further validate its therapeutic potential.

Adult↗
PubMed1997

[Radiation-induced meningioma: the changing pattern of the disease].

In this country radiation-induced meningiomas were usually associated with low-dose irradiation of the scalp of immigrants from North Africa, given as part of the treatment of tinea capitis. An Ashkenazi patient developed meningiomas 15 years after high-dose irradiation for a benign lesion in the parasellar region. The accumulating literature about high-dose radiation-induced meningiomas is reviewed and attention is drawn to the ever increasing number of meningiomas observed in immigrants from the former Soviet Union.

Brain Neoplasms↗
PubMed1997

[Temporal hemianopia and diabetes insipidus following head injury].

Bitemporal hemianopia and diabetes insipidus following head injury are caused by a lesion in the center of the optic chiasm, together with injury to the adjacent pituitary stalk or the hypothalamus. This combination was thought to be a rare complication of severe head injury. The case of a 16-year-old male is presented, which together with recent reports suggests that this relatively under-recognized syndrome is not infrequent, that it may follow even minor head injury, and that magnetic resonance imaging can demonstrate the chiasmal lesion.

Adolescent↗
PubMed1997

Neurobehavioral consequences of closed head injury in the elderly.

The assessment of neurobehavioural outcome after head injury in older patients (> 60 year old) has met with difficultives, due to the obstacles in finding subjects who would constitute an appropriate control group. In the present study, survivors of closed head injury (CHI) of this age group were compared to two control groups: (1) orthopaedic patients (OP) who were injured in similar circumstances but did not sustain head injury and (2) healthy, age-matched volunteers (HC). Compared with HC, CHI and OP were impaired on word fluency, memory and reasoning. No differences were found between CHI and the OP. These results may indicate that, rather than resulting only from the head injury brought about by falling, the cognitive decline may predate the injury and increase the risk of accidents in old age.

Accidental Falls↗
PubMed1997

Three head injuries: the Biblical account of the deaths of Sisera, Abimelech and Goliath.

Three head injuries are described in the Bible: the death of Sisera at the hands of Jael, the skull fractures inflicted on Abimelech near the walls of Thebez, and the slaying of Goliath by David. The various attempts to understand the mechanisms of these head injuries are reviewed. We shall try to identify the site of the mortal blow on Sisera's head, to understand why Abimelech, still conscious, asked to die, and to clarify whether the Philistine giant from Gat was a rugged warrior or just an endocrinological cripple.

Bible↗
PubMed1997

Motor evoked potentials in the preoperative and postoperative assessment of normal pressure hydrocephalus.

Motor evoked potentials and central motor conduction time (CMCT) were examined from both upper and lower limbs in patients with normal pressure hydrocephalus to find a predictor for the success of shunting procedures. The hypotheses that walking disturbances are due to pyramidal tract compression as well as the possibility that the upper limbs are affected subclinically in these patients were also studied. The study suggests that the walking disturbances are not the result of a major pyramidal tract dysfunction but probably involve the sensorimotor integration leading to normal gait. Furthermore, CMCT measured with electromagnetic motor stimulation can help in selecting the patients that will benefit from shunting. The study does not provide electrophysiological evidence of upper limb involvement in normal pressure hydrocephalus.

Adult↗
PubMed1997

[An achondroplastic dwarf with paraplegia].

A 30-year-old female achondroplastic dwarf developed a progressive gait disturbance erroneously attributed to her hydrocephalus and deformities of both legs. Her condition deteriorated into flaccid paraplegia with anal and urinary incontinence. CT revealed extreme spinal stenosis typical in achondroplasia (shallow vertebral body, short pedicles, and hypertrophy of intervertebral joints) together with disc protrusions. Wide laminectomy of the lumbar vertebrae resulted in complete amelioration of all the neurological deficits. Progressive paraplegia is a rare complication of achondroplasia; its early recognition and surgical treatment is very rewarding.

Achondroplasia↗
PubMed1996

[Motor potentials evoked by magnetic stimulation--a tool for objective assessment of motor conduction along the spinal cord and its roots].

Magnetic stimulation of the motor cortex and nerve roots in conjunction with F-wave recording was used for assessment of central and peripheral motor conduction times in 98 patients suffering from myelopathy and cervical or lumbo-sacral radiculopathy. Significant prolongation of the central motor conduction times was found in the myelopathy group. The Motor Evoked Potential was of low amplitude and distorted shape. The amplitude of the F-wave was markedly increased. The main feature of the radiculopathy group was prolonged motor root conduction time as evident by delayed F-wave. Motor evoked potentials proved to be a reliable objective tool in the functional evaluation of conduction along the spinal cord and its roots.

Evoked Potentials, Motor↗
PubMed1996

Brain-stem trigeminal and auditory evoked potentials in multiple sclerosis: physiological insights.

Thirty-six patients with multiple sclerosis were evaluated by means of brain-stem trigeminal and auditory evoked potentials. The brain-stem auditory evoked potentials (BAEPs) were abnormal in 26 patients (72.2%). Brain-stem trigeminal evoked potentials (BTEPs) yielded similar results, showing distorted waveforms and/or prolonged latencies in 25 patients (69.4%). As expected, the MRI proved to be the most efficient single test, revealing plaques in 86.4% of the patients evaluated. However, the diagnostic accuracy of MRI was lower than that provided by the combination of the BTEP and BAEP (88.9%). Moreover, in patients having signs of brain-stem involvement, the BTEP, alone and in combination with the BAEP, proved to be more sensitive than the MRI in revealing brain-stem lesions. Correlation between clinical and BTEP findings could be found only in those patients who presented with signs of trigeminal involvement such as trigeminal neuralgia or dysesthesiae. The analysis of the BTEP waveforms showed two distinct types of abnormality-a peripheral type and a central type-suggesting plaques in distinct locations. Both the BTEP and the BAEP demonstrated a correlation with the clinical course of the disease and the condition of the patient at the time of the evaluation. Relapse of the disease was associated with a marked prolongation of the central conduction time in the BTEP and in the BAEP, suggesting the application of such studies to the monitoring of unstable patients in the evaluation of new therapeutic protocols.

Adolescent↗
PubMed1996

Intracranial recording from the brain-stem and the trigeminal nerve following upper lip stimulation.

Short latency evoked potentials following stimulation of the upper lip were recorded intracranially during neurosurgical procedures in 14 patients. In 10 patients, a suboccipital craniectomy provided direct access to the trigeminal root and the pons at the root entry zone. Direct recordings from the trigeminal root were characterized by a large triphasic potential at 2.4-2.7 msec. The latency of this potential increased as a result of moving the recording electrode proximally towards the brain-stem. The same potential could be recorded from the brain-stem surface at a latency suggesting an intra-axial presynaptic origin. A second component, N4.7, was recorded from over the most rostral aspect of the brain-stem in 3 patients and from the tentorium free edge in 4 patients. This potential of smaller amplitude did not show significant difference in latency or polarity at various electrode locations, suggesting a deep diencephalic origin remote from the recording electrode.

Brain↗
PubMed1996

A comparison of neural network and Bayes recognition approaches in the evaluation of the brainstem trigeminal evoked potentials in multiple sclerosis.

This article describes the application of Multi-Layer Perceptron (MLP), Probabilistic Neural Network and Kohonen's Learning Vector Quantization to the problem of diagnosing Multiple Sclerosis. The classification information is obtained from brainstem trigeminal evoked potential. The performance of the neural networks based classifiers is compared with that of the human experts and the Bayes classifier. The ability of the MLP classifier to generalize is far better than that of the Bayes classifier. The efficiency of the neural network based classifiers in conjunction with several types of well-known evoked potential features, such as Fourier transform space, latency and temporal wave, is examined. Although a large clinical data base would be necessary, before this approach can be fully validated, the initial results are promising.

Bayes Theorem↗
PubMed1996

A compartmental brain model for chemical transport and CO2 controlled blood flow.

A compartmental transport model is developed, capable of predicting the evolution of CO2, HCO-3 and H+ in the cerebrovascular system. In the model, the transport of these components is simulated at a subset of three compartments: cerebrospinal fluid (CSF), capillary-choroid plexus and brain tissue, belonging to a seven compartmental assembly representing the entire brain. The remaining ones are; artery, vein, venous sinus and jugular bulb. The model accounts for advection associated with non-steady perfusion fluxes across semi-previous boundaries. Pressures, associated with perfusion, are solved in the seven-compartment model. The three-compartment transport model also takes into account changes in compartmental volume due to displacement of its boundaries, diffusion through boundaries and rate of generation of substances by chemical reactions. A first-order reaction rate is assumed in the CSF compartment. A parameter estimation method is then developed to assess boundary diffusivities from time-averaged observed values of perfusion pressure, tension of carbon dioxide, pH values, and concentration of free hydrogen and bicarbonate ions. An equation of state describing the regulation of flow from arteries to capillaries, as a function of CO2 tension in the CSF, is then suggested. Upon solving all coupled mass balance equations, and for a pre-evaluated perfusion pressure in the artery and capillary compartments, one can estimate the change in arteries to capillaries conductance at every time step. Boundary diffusivities between the capillary, cerebrospinal fluid and brain tissue compartments, were estimated. A sensitivity analysis proves the consistency between model predictions and available clinical observations, this, in terms of the influence of the parameter associated with CO2 metabolic rate on CO2 tension. It was shown that decrease of this tension caused an abrupt pressure fall at the first instant which later increased to an asymptotic value. This, however, was not evident in the capillaries at which pressure slightly falls and then remains constant.

Bicarbonates↗