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Biomedical subjects

L Pollak

Publications and source records attributed to L Pollak.

At least 19 recordsLinked to original sources
PubMed2006

Diagnostic value of vestibular evoked myogenic potentials in cerebellar and lower-brainstem strokes.

BACKGROUND: Vestibular evoked myogenic potentials (VEMPs) provide assessment of vestibular function. They consist in picking up compound muscle action potentials in the sternocleidomastoid (SCM) muscles in response to auditory stimulation of the vestibulum. VEMP testing has found application mainly in peripheral vestibular disorders, whereas reports about VEMPs in central vestibular lesions are rather scarce. AIMS OF THE STUDY: Based on the physiological connections between the cerebellum and the vestibular nuclei, we investigated the influence on VEMPs of cerebellar and lower-brainstem strokes. We examined whether or not this method may be suitable as a clinical tool for the evaluation of the extent of cerebellar strokes. PATIENTS AND METHODS: Nineteen patients with cerebellar ischemic stroke and 15 patients with lower-brainstem ischemic stroke (11 in the pons, four in the medulla) were included. The latencies and amplitudes of P13 and N23 in both groups of patients were compared with those obtained in a control group of 53 normal individuals. RESULTS: VEMP responses were obtained in all patients and controls. At the group level, mean peak latencies and amplitudes, and the number of subjects with significantly deviant values did not differ between patients and controls. There were no latency or amplitude differences ipsilaterally or contralaterally to the lesion. At the individual level, there was no correlation between laterality of lesion and that of P13 or N23 abnormalities in patients with cerebellar strokes; however, there were two patients (one pontine, one medullar stroke) who presented P13 and N23 latency abnormalities ipsilaterally to the lesion. CONCLUSION: Cerebellar strokes do not influence VEMPs. Moreover, despite previous reports, we were unable to find at a group level any statistically significant VEMP changes in patients with lower-brainstem strokes as compared with controls. Therefore, VEMPs do not appear a suitable tool for assessment of brainstem integrity in patients with posterior fossa strokes. However, they could constitute a sensitive method for documentation of involvement of the central vestibular pathways in patients with brainstem stroke.

Acoustic Stimulation↗
PubMed2005

Infectious inflammation of the CNS involves activation of mitogen-activated protein kinase and AKT proteins in CSF in humans.

The mitogen-activated protein kinases (MAPKs) and the AKT are interacting proteins that serve as transmitters of numerous extracellular signals to their intracellular targets, thereby regulating many cellular processes, such as proliferation, differentiation, development or stress responses. Whereas a large amount of information about the MAPKs/AKT participation in biological processes is available, less is known about their role in human diseases. We postulated that the MAPKs/AKT could be involved in inflammatory processes of the central nervous system (CNS) in humans and we investigated the CSF of 12 patients with viral infection of the CNS for the presence of the distinct components of these cascades. The cerebrospinal fluid (CSF) of 18 individuals who underwent a lumbar puncture for diagnostic purposes served as controls. Six patients with inflammatory disease of the CNS revealed the presence of activated ERK. In five patients p38MAPK was detected, in three in its activated form. The activity of AKT could be demonstrated in four patients. JNK was not found. None of the control patients showed the presence of MAPK enzymes. The mean CSF cellularity was higher in MAPK-positive than in MAPKnegative patients. There was no difference in mean age or gender between the patients and controls, or between the MAPK- and AKT-positive or -negative patients. Our work demonstrates that the MAPK and AKT cascades might participate in inflammatory processes of the CNS. As selective inhibitors of the MAPKs are available, their application in the future might reduce an inappropriate inflammatory response and thus limit brain damage in severe cases of meningoencephalitis.

Adolescent↗
PubMed2005

Clinical characteristics of patients with ischemic ocular nerve palsies and lacunar brain infarcts: a retrospective comparative study.

BACKGROUND: Ischemic ocular motor nerve palsies (IOMP) and lacunar brain infarcts share a similar pathological mechanism. The clinical characteristics of patients as well as the protective role of aspirin should therefore be similar in both conditions. METHODS: The medical records of 107 consecutive patients with IOMP and 160 patients with lacunar cerebrovascular accidents (CVA) were reviewed and analyzed with respect to patient characteristics, vascular risk factors, and aspirin intake. The data on patients with and without aspirin were compared within each group as well as between both groups. RESULTS: Hyperlipidemia, smoking, high carotid stenosis (>70%) and the presence of more than one vascular risk factor in an individual patient were found to be more common in patients with lacunar brain infarcts regardless of aspirin intake. Absence of vascular risk factors was encountered more in IOMP patients. The recurrence of lacunar CVA was significantly higher than recurrence of IOMP. A history of Bell's palsy was more common in IOMP patients than in patients with lacunar CVA. Within the IOMP group, the prevalence of vascular risk factors did not differ between the aspirin and non-aspirin group. Ischemic heart disease (IHD), CVA and recurrence were found more often in the aspirin group. Within the CVA group hypertension, IHD, cardiac arrhythmia and recurrence rate were more common in the aspirin group whereas smoking was found to be more common in the non-aspirin group of patients. CONCLUSIONS: Arteriosclerosis is the main cause of lacunar CVA and IOMP. However, IOMP depends less on the presence of vascular risk factors than does lacunar CVA. Furthermore, aspirin - at least at low doses - does not seem to have a protective effect on either of these conditions, but more extensive prospective studies of homogeneous groups of patients are needed to clarify the preventive role of antiplatelet agents in IOMP.

Aged↗
PubMed2004

Polysomnography in patients with intracranial tumors before and after operation.

OBJECTIVE: To evaluate the breathing and sleep patterns in patients with brain tumors before and after operation, and assess their relation to the location and size of the tumor, as well as to the post-operative outcome. METHODS: Polysomnographic studies were performed in 11 patients with intracranial tumors (nine supra- and two infratentorial) before and after surgery. RESULTS: Pre-operatively, the mean apnea-hypopnea index (AHI) was 23.3. Six patients demonstrated signs of obstructive sleep apnea (SA) and one had mixed obstructive and central type SA. After operation, the mean AHI decreased to 8.1(P < 0.05). The duration of random eye movement sleep stage increased after tumor removal (P < 0.04). No relation was found between the characteristics of the tumor, nor the post-operative outcome and SA. CONCLUSIONS: Patients with brain tumors often suffer from SA and this can further worsen their symptoms related to increased intracranial pressure. Removal of the tumor results in a substantial decrease in sleep-related disturbances and may thus play a role in clinical recovery.

Adult↗
PubMed2002

Neurological features of West Nile virus infection during the 2000 outbreak in a regional hospital in Israel.

During the summer of 2000, 35 patients with West Nile Virus Fever were admitted to our hospital. Of these, the 26 (21 adults, mean age 56 (19-86) and 5 children (aged 9-15)) presented have neurological involvement, 33% with meningitis, 52% with meningoencephalitis, 10% with encephalitis and 5% with acute polyneuropathy. Presenting clinical features were fever in 95% of cases, headache in 90%, nausea/vomiting in 52%, confusion in 48%, somnolence in 38%, neck stiffness in 33%, a skin rash in 19%, diarrhea in 14%, cervical pain in 14%, seizure in 9%, photophobia in 9% and limb weakness in 4%. Leucopenia was not found. Two patients diagnosed with meningoencephalitis died. Three patients had signs of an acute polyneuropathy, this being the only complaint of one patient. The EEG was abnormal in all cases of meningitis or meningoencephalitis, except in three cases. Outbreaks of West Nile Virus Fever are emerging as a worldwide disease with high rates of neurological involvement and death. It should be considered in cases presenting with aseptic meningoencephalitis, meningitis and acute polyneuropathy, especially during the summer months and in areas along bird migration pathways.

Adolescent↗
PubMed2002

Comparison of glatiramer acetate (Copaxone) and interferon beta-1b (Betaferon) in multiple sclerosis patients: an open-label 2-year follow-up.

OBJECTIVE: To compare the clinical efficacy, as expressed by relapse rate and disability accumulation, and safety profile of glatiramer acetate (Copaxone; COP-1) and Interferon beta-1b (Betaferon; IFN beta - 1b) administered to multiple sclerosis patients during a 2-year follow-up on an open-label parallel design, as compared to their clinical condition in the 2-year period prior to treatment. BACKGROUND: Copaxone and IFN beta - 1b have been recently introduced for the treatment of relapsing forms of MS. Both medications have been proven to have a relatively safe profile and are used extensively world-wide. METHODS: 58 consecutive patients with relapsing forms of MS were enrolled from the MS out-patient clinic, during three months. After being informed in detail of the two approved treatment options existing at the time in Israel, the patients chose by themselves to receive either: (a) Copaxone 20 mg subcutaneously (sc) daily (Copaxone dly, 20 patients), or (b) Copaxone 20 mg sc alternate-day (Copaxone alt, 18 patients) or (c) IFN beta-1b 8 MIU sc in alternate day (20 patients). Mean relapse rate/year and mean EDSS/year were calculated for each group of patients during the 2 years prior to the onset of treatment, and during the year prior to the onset of treatment. Statistical significance was observed in the relapse rate in the year prior to the onset of treatment between the IFN beta -1b group and the two Copaxone groups (p = 0.05). This statistical difference has no effect on the overall data of the 2 years prior to starting the treatment and on the results. No statistical significance was observed in the total number of relapses, and on the 2-year relapse rate, prior to the onset of treatment. Mean relapse rate/year and mean EDSS/year were calculated for each group during the first and second year of treatment. Wilcoxon analysis for clinical data and chi-square for adverse events were applied. RESULTS: The three groups were statistically comparable concerning mean relapse/year in the 2 years before the trial started and no statistical significance was observed among the three groups. A statistically significant reduction in the mean relapse rate in the 2 years after onset of treatment was observed in the three group of patients: Copaxone daily (dly) 1.1 +/- 0.6 (p = 0.0001); Copaxone alternate (alt) 0.9 +/- 0.6 (p = 0.0004) and IFN beta -1b 1.2 +/- 0.7 (p = 0.0001). Disability as expressed by EDSS score prior to the onset of treatment and after 2 years of treatment showed deterioration in the three groups although more significant in the Copaxone groups: Copaxone dly 3.3 +/- 1.4 to 3.8 +/- 1.6 (p = 0.007); Copaxone alt 2.4 +/- 1.1 to 2.8 +/- 1.3 (p=0.04); IFN beta - 1b 3.1 +/- 1.3 to 3.3 +/- 2.0 (N.S.). The most common adverse events reported were: (1) flu-like symptoms 7 pts (35%) in the IFN beta -1b group; 10 pts (26%) of the two Copaxone groups; (2) increased spasticity of lower limbs 3 pts (15%), only in the IFN beta -1b group; (3) site injection reaction (SIR): 16 SIR (80%) in the IFN beta -1b group; 12 SIR (67%) in the Copaxone alt group; 14 SIR (70%) in the Copaxone dly group; and (4) systemic reaction 3 pts (15%) in the IFN beta -1b group; 4 pts (22%) in the Copaxone alt group; 6 pts (30%) in the Copaxone dly group. Premature termination occurred in five patients treated with Copaxone (3 in the alternate group and 2 in the daily group). CONCLUSION: The present study, despite the limitations of an open-label study, shows that Copaxone dly, Copaxone alt and IFN beta -1b treatment seem to be equally effective for the control of exacerbations in MS. The adverse event profile, as reported by the patients, was also similar. However, the adverse events profile registered indicated that Copaxone is somewhat less detrimental, whereas disability as measured by EDSS accumulation showed that the interferon beta - 1b patients demonstrated a slower progression of the disability.

Adjuvants, Immunologic↗
PubMed2001

Electroencephalographic abnormalities in aseptic meningitis and noninfectious headache. A comparative study.

BACKGROUND: The finding of abnormalities on electroencephalogram (EEG) during the course of aseptic meningitis is often considered to be indicative of parenchymal brain involvement, even in absence of clinical signs of encephalitis. OBJECTIVE: To investigate if patients with aseptic nonherpetic meningitis who have abnormal EEG recordings during the acute stage of the disease differ in clinical characteristics or cerebrospinal fluid findings from patients with aseptic meningitis and normal EEG recordings. METHODS: The EEG records of 82 patients with aseptic meningitis were reviewed. A comparative group consisted of 41 age-matched patients with severe headaches without evidence of meningeal inflammation. RESULTS: Significantly more patients with aseptic meningitis (28%) demonstrated abnormalities on EEG than controls (12%) (P =.048). Patients with aseptic meningitis and abnormal EEG findings (n = 23) did not differ in age, duration of symptoms, clinical course, cerebrospinal fluid cell count, or protein level from those with normal EEG findings (n = 59). However, all patients with aseptic meningitis who were confused (n = 5) also revealed EEG abnormalities (P<.00012). Patients with headache with normal EEG recordings did not differ from those with abnormal EEGs in age, sex, or duration of symptoms. Nevertheless, patients with common migraine (n = 9) showed abnormalities on EEG (P =.06) more frequently. CONCLUSIONS: The finding of an abnormal EEG in patients with aseptic meningitis, clear mental state and absence of focal neurological signs should not be used as proof of encephalitis. Because pathological examination is usually not performed, it remains unclear if EEG abnormalities in patients with aseptic meningitis indicate a silent parenchymal inflammation, or reflect an infectious encephalopathy.

Acute Disease↗
PubMed2001

Visual vertigo: symptom assessment, spatial orientation and postural control.

Certain patients with balance disorders report a 'visual vertigo' in which their symptoms are provoked or aggravated by specific visual contexts (e.g. supermarkets, driving or movement of objects). In order to determine the causes of visual vertigo (VV), we assessed symptoms, anxiety and the influence of disorienting visual stimuli in 21 such patients. In 17 out of 21 patients, a peripheral vestibular disorder was diagnosed. Sixteen bilateral labyrinthine-defective subjects (LDS) and 25 normal subjects served as controls. Questionnaire assessment showed that the levels of trait anxiety and childhood motion sickness in the three subject groups were not significantly different. Reporting of autonomic symptoms and somatic anxiety was higher than normal in both patient groups but not significantly different between LDS and VV patients. Handicap levels were not different in the two patient groups, but the reporting of vestibular symptoms was higher in the VV than in the LDS group. The experimental stimuli required subjects to set the subjective visual vertical in three visual conditions: total darkness, in front of a tilted luminous frame (rod and frame test) and in front of a large disc rotating in the frontal plane (rod and disc test). Body sway was also measured in four visual conditions: eyes closed, eyes open, facing the tilted frame and during disc rotation. In psychophysical and postural tests, both LDS and VV patients showed: (i) a significant increase in the tilt of the visual vertical both with the static tilted frame and with the rotating disc; and (ii) an increased postural deviation whilst facing the tilted frame and the rotating disc. The ratio between sway path with eyes closed and eyes open (i.e. the stabilizing effect of vision) was increased in the LDS, but not in VV patients, compared with normal subjects. In contrast, the ratio between sway path during disc rotation and sway path during eyes open (i.e. the destabilizing effect of a moving visual stimulus) was increased in the VV patients but not in LDS. Taken together, these data show that VV patients have abnormally large perceptual and postural responses to disorienting visual environments. VV is not related to trait anxiety or a past history of motion sickness. The results indicate that VV emerges in vestibular patients if they have increased visual dependence and difficulty in resolving conflict between visual and vestibulo-proprioceptive inputs. It is argued that treating these patients with visual motion desensitization, e.g. repeated optokinetic stimulation, should be beneficial.

Adult↗
PubMed2001

Labyrinthine involvement in Behçet's syndrome.

We report the neuro-otological findings in 26 consecutive patients with definite and probable Behçet's syndrome unselected for audiovestibular complaints. Auditory and/or vestibular abnormalities were found in 19 (73 per cent) patients, with auditory involvement in 14 (54 per cent) and vestibular in 10 (38.5 per cent) of patients. Peripheral involvement was more common than central involvement for both auditory and vestibular lesions. Bilateral cochlear hearing impairment was the most common audiological finding, whereas unilateral peripheral dysfunction was the prevailing vestibular abnormality. No correlation has been found between audiovestibular lesions and other organ lesions, disease duration or age or sex of the patients. Moreover, there was a lack of interdependence between cochlear and vestibular labyrinthine lesions. We conclude that a full neuro-otological assessment in patients under investigation for Behçet's syndrome may reveal labyrinth involvement in a substantial proportion of patients. In view of the absence of a specific diagnostic test for Behçet's syndrome, audiovestibular lesions may provide further diagnostic support for this disorder.

Adult↗
PubMed2000

Body packer: cocaine intoxication, causing death, masked by concomitant administration of major tranquilizers.

Cocaine, derived from the leaves of the shrub Erythroxylon coca, which grows on the slopes of the Andes, remains one of the most widely abused illicit drugs (Johnson et al., 1993). Its abuse appears to be increasing and as a result, so is its trafficking across borders, with ever-increasing sophistication of concealment (Rouse, 1992). Over the past few years, cases of cocaine intoxication have been reported, resulting from ruptured packets of cocaine that have been swallowed, or inserted into the vagina or rectum by couriers (drug smugglers), so called 'body packers' or 'mules' (Westli and Mittleman, 1981; Ricaurte and Langston, 1995). Cocaine is a powerful sympathomimetic and central nervous system stimulant, an overdose of which causes primarily cardiac, neurological and psychiatric effects (Ricaurte and Langston, 1995). Acute toxicity is dose-related and is characterized in the first place by its sympathomimetic effects, which include tachycardia, hypertension and hyperthermia arrythmias, followed by seizures. Brainstem depression and cardio-respiratory collapse, stroke, coma, intracranial vasculitis, myocardial infarction and sudden death have all been reported in cocaine abuse (Ricaurte and Langston, 1995). We present a fatal case with neurological and psychiatric symptoms, but without the usual cardiac and systemic signs.

Adult↗
PubMed1999

Revival of non-surgical management of neonatal depressed skull fractures.

The management of depressed skull fractures in the newborn infant can be controversial. We report on a neonate, born by Caesarean section with difficult head extraction, complicated by a parietal depressed fracture. This 'ping-pong' fracture was treated by elevation with an obstetrical vacuum extractor. No complications occurred. The possible treatment modalities for neonatal depressed fractures, being conservative or operative, will be discussed.

Adult↗
PubMed1999

Hartshill spinal fixation in vertebral metastasis.

Spinal fusion by Hartshill rectangle frame was used in 10 patients with spinal cord compression secondary to vertebral metastasis in the thoracic and lumbar spine, occupying mainly the posterior elements. All patients presented with pain, bone collapse, and neurologic deficit. The procedure is built on a system of sublaminar wires passed under two to three lamina above and below the decompressed area and tightened to a prebent metal frame. This procedure was relatively simple, and the immediate stabilization achieved in our patients was good. All patients experienced immediate pain relief. While only two patients were able to walk before surgery, seven were able to do so at follow-up. During a follow-up period of at least 2 years in two patients, or until death in the other eight patients, one patient had a broken wire that did not affect the correction achieved at surgery. Partial loss of correction in the sagittal plane was found in two patients who had metastasis in the lumbar spine and in another patient who had metastasis in the ninth thoracic vertebra.

Adenocarcinoma↗
PubMed1998

Neurosurgical intervention for cervical disk disease in dystonic cerebral palsy.

We report five young patients with athetoid-spastic cerebral palsy who had deteriorated neurologically. Magnetic resonance imaging (MRI) was used to investigate suspected compressive cervical spine lesion. Cervical spondylosis with disk protrusions was found in all patients. Four patients underwent surgery by an anterior approach with insertion of a bone graft resulting in substantial clinical improvement. The other patient, diagnosed 8 years after onset of symptoms, was treated conservatively. The availability of MRI makes early recognition of cervical cord compression possible, allowing effective surgical intervention in this special group of patients.

Adult↗
PubMed1998

Indication to surgical management of cerebellar hemorrhage.

Few reports have compared patients operated for cerebellar infarcts with those operated for cerebellar hemorrhage. Considering our previous paper about patients with massive cerebellar infarcts, we report on our surgical experience with five patients with cerebellar hemorrhage. The indication for operation was decreased consciousness with signs of brainstem compression. In all patients hydrocephalus was absent or mild, as opposed to patients with cerebellar infarcts. Suboccipital craniotomy with hematoma evacuation was therefore the surgical procedure of choice. The outcome was worse than in patients with cerebellar infarcts. We conclude that depressed mental state in cerebellar hemorrhage is mainly due to pressure of the cerebellum on the activating reticular system of the brainstem. The surgical approach to patients with bleeding in the cerebellum differ somewhat from that of patients with cerebellar infarcts in timing and kind of first choice procedure.

Aged↗