C Klein

Tel Aviv University, Tel Aviv, Tel Aviv, Israel

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Publications (49)128.46 Total impact

  • [show abstract] [hide abstract]
    ABSTRACT: To evaluate the immediate and short-term effects of repeated within session trials on N1, P2, N2 and P3 latencies and P2, N2 and P3 amplitudes in healthy adults. ERPs were elicited by the auditory oddball paradigm and recorded over Fz, Cz and Pz in 18 healthy adults over two sessions, one to three days apart, and two within session trials with one to three minutes trial-retrial interval. The ERPs' latencies and amplitudes were blindly calculated and were analyzed by Analysis of Variance (ANOVA) with repeated measures. Significant decreases of N2 amplitude at Fz, P3 amplitude at Cz and P3 latency at Pz were recorded in the second-compared to the first within session trial (p=0.034, 0.041, 0.046, respectively). There were no significant inter-session differences regarding N1, P2, N2 and P3 latencies or amplitudes. There was no significant interaction between session and trial. A statistically significant difference was found between the first session's mental count errors (p=0.039) but there were no significant differences between the second session's trials (p=0.581) or between sessions (p=0.328). N1, P2, N2 and P3 latencies and amplitudes are stable at short-term intervals of one to three days, but one to three minutes' retrial interval may affect P3 latency and N2 and P3 amplitudes. We suggest that when primary novelty-induced cognitive processes are evaluated, single trial sessions or more than three-minute inter-trials interval should be employed in order to mitigate habituation.
    Journal of neuroscience methods 10/2009; 186(1):77-80. · 2.30 Impact Factor
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    ABSTRACT: Acute herpes simplex encephalitis (HSE) has a grave outcome, and detection of prognostic features is of clinical importance. Thirty patients with HSE were assessed in a retrospective study. Diagnosis was confirmed by serological methods using the indirect immunofluorescence technique (IFT). Antiviral treatment was given to 23 of the patients. Focal convulsions were more frequent in patients below 18 years of age, while confusion and memory disturbances were prevalent among patients above 18. The final outcome was influenced by the degree of severity of the disease at the peak and the state of consciousness and duration of disease prior to the initiation of anti-viral treatment. No correlation was found between antibody levels in serum or in CSF and the outcome. We conclude that the clinical degree of severity the duration of illness prior to treatment and state of consciousness at the initiation of anti-viral treatment are of prognostic importance.
    Acta Neurologica Scandinavica 01/2009; 93(2-3):149-55. · 2.47 Impact Factor
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    ABSTRACT: To investigate the frequency of axonal Guillain-Barre syndrome (GBS) in our ward over 6 years (1999-2005). Clinical and electrophysiological findings of 40 patients admitted to neurology with abnormalities compatible with acute motor axonal neuropathy (AMAN), acute motor sensory axonal neuropathy (AMSAN) and acute inflammatory demyelinating polyneuropathy (AIDP) were reviewed. Electrophysiological findings showed that 25 (63%) patients had AIDP, nine (22%) AMAN and six (15%) AMSAN. There were significant differences in disease severity. Most axonal patients (87%) were hospitalized with moderate or severe symptoms (3-4 Hughes grade score) and progressed to severe grade (4-6) in comparison with AIDP patients (64% admitted with mild forms) (1-2 Hughes grade score) and progressed to severe in 44% of cases. Cranial nerve involvement was more frequent in AIDP (56%) in comparison with the axonal type (13%). Raised cerebrospinal fluid protein at the time of hospitalization was observed in 76% of demyelinating and 33% of axonal patients. Axonal GBS occurred more frequently in Israel compared with other Western countries.
    Acta Neurologica Scandinavica 06/2008; 117(5):347-50. · 2.47 Impact Factor
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    ABSTRACT: We report three patients with a typical clinical picture of unilateral meralgia paresthetica in whom routine nerve conduction studies were normal. However, cortical somatosensory evoked potentials were absent after lateral femoral cutaneous nerve (LFCN) stimulation on the affected side. After stimulation of the LFCN in the anterosuperior iliac spine (ASIS) region and recording the responses distal to conventional sites (20 cm from the ASIS), sensory nerve action potentials (SNAPs) were absent in the symptomatic leg, but present in the normal leg. We suggest that thigh paresthesias may be caused by a distal LFCN lesion. Eliciting this requires recording SNAPs distal to conventional sites.
    Muscle & Nerve 02/2008; 37(1):101-3. · 2.31 Impact Factor
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    ABSTRACT: Carotid artery stenting is used as an alternative to surgical endarterectomy. To determine the outcome of CAS in a retrospective cohort of patients. Between July 1999 and March 2003, 56 consecutive patients with carotid artery stenosis who were considered ineligible for surgery were treated (45 males, 11 females, mean age 69). All underwent the procedure prior to the introduction of distal protective devices in Israel. Intraprocedural complications included transient neurological findings in 5 patients (8%), cerebrovascular accident in 2 (3%), hemodynamic changes in 11 (18%), and 4 procedural failures. Post-procedural complications included transient ischemic attack in 3 patients and cardiovascular accident in 6 (10%). At 30 days follow-up, three patients (5%) remained with signs of CVA. Two patients (3%) died during the post-procedural period and 16 (28%) during the 5 year follow-up, one due to recurrent CVA and the remainder to non-neurological causes. Five-year carotid Doppler follow-up was performed in 25 patients (45%), which revealed normal stent flow in 21 (84%), 50-60% restenosis in 3 (12%) and > 70% restenosis in one patient (4%). This study confirms that stent procedures are beneficial for symptomatic carotid stenosis in patients not eligible for surgery.
    The Israel Medical Association journal: IMAJ 02/2008; 10(2):121-4. · 0.98 Impact Factor
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    ABSTRACT: Phenytoin is a first-line drug for the treatment of status epilepticus. We report a case of phenytoin intoxication after intravenous phenytoin loading in a patient with clozapine-related seizures. To our knowledge, this is the first description of phenytoin intoxication due to CYP2C9 inhibition by clozapine. This case report is important because it supports the use of a lower intravenous loading dose of phenytoin in patients with clozapine-related status epilepticus.
    Journal of Emergency Medicine 11/2007; 35(4):407-9. · 1.33 Impact Factor
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    ABSTRACT: This double-blind randomized study examined the effect of quetiapine (QTP) on drug-induced psychosis (DIP) in Parkinson's disease (PD). Conventional antipsychotic drugs are associated with adverse extrapyramidal effects. QTP is a new atypical antipsychotic drug used in the treatment of psychosis in PD. A total of 58 consecutive psychotic PD patients (mean age, 75 +/- 8.3 years; mean disease duration, 10.5 +/- 6.4 years; 29 with dementia) were randomly assigned to 2 groups: 30 were treated with QTP (mean dose, 119.2 +/- 56.4 mg) and 28 received placebo for 3 months. The motor part of the Unified Parkinson's Disease Rating Scale, the Brief Psychiatric Rating Scale, the Mini-Mental State Examination, the Hamilton Rating Scale for Depression, the Epworth Sleepiness Score, and the Clinical Global Impression Scale were administered before and during the study. No significant difference was found between the groups in all parameters. There were 32 PD patients (55%) completed the 3-month study (15 [26%] QTP and 17 [29%] placebo). Treatment was interrupted in 15 patients in the QTP and 11 in the placebo groups. This double-blind study did not show a beneficial effect of QTP for the treatment of DIP in PD. The high rate of withdrawal probably influenced the results. Larger double-blind studies are required.
    Movement Disorders 03/2007; 22(3):313-8. · 4.56 Impact Factor
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    ABSTRACT: The objective of this study is to compare the occurrence of dementia among Parkinson's disease (PD) patients treated with amantadine (AM group) with those never exposed to it (NoAM group). PD dementia shares neuroanatomical and biochemical similarities with Alzheimer's disease (AD). Memantine, an N-methyl-D-aspartate (NMDA) receptor antagonist has been shown to be beneficial in AD. Memantine is a dimethyl derivative of amantadine, which also possesses NMDA receptor blocking properties. We hypothesized that amantadine could have a beneficial effect on the occurrence of PD dementia. PD patients attending the Movement Disorders Clinics in Hillel Yaffe, Asaf Harofe Medical Centers (Israel) and Pisa (Italy) were included. Taking the onset of dementia as the endpoint, survival curves for AM and NoAM patients were estimated by the Kaplan-Meier method. The study population consisted of 593 patients (age, 69.5 +/- 9.9 years; PD duration, 9.2 +/- 6.0 years; 263 patients (44%) amantadine treated). The endpoint of dementia was reached by 116 patients (20%). PD duration until dementia was significantly longer for AM patients (9.1 +/- 5.7 years) than for NoAM patients (5.9 +/- 4.6 years, P = 0.006). The duration of amantadine exposure positively correlated with PD duration until dementia (P = 0.0001). Survival analysis, taking dementia onset as endpoint, showed slower mental decline in AM patients (Log rank P = 0.0049, Wilcoxon P = 0.0024). Mini-Mental State Examination scores were significantly higher for AM patients than for the NoAM group (P = 0.01). Age of PD onset also significantly influenced the duration of PD until dementia. Amantadine use may delay the onset of dementia in PD patients and may attenuate its severity.
    Movement Disorders 10/2006; 21(9):1375-9. · 4.56 Impact Factor
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    ABSTRACT: To investigate excessive daytime sleepiness (EDS) in patients with Parkinson's disease (PD), the reasons for which have not yet been clarified, polysomnography (PSG) and the Multiple Sleep Latency Test (MSLT) were performed in 46 patients with PD, and, in addition, PSG was performed in 30 healthy controls. Assessment included Epworth Sleepiness Score (ESS), Mini-Mental State Examination (MMSE), and Hamilton Test (HT) for depression. Fifty percent of PD patients reported EDS (ESS, 10 +/- 4.5 vs. 6.9 +/- 3.7; P = 0.01). Compared with controls, PD patients as a group had lower sleep efficiency (65 +/- 22 vs. 77 +/- 14; P = 0.03), a longer Stage 2 (73 +/- 12 vs. 67 +/- 12; P = 0.03), and a shorter rapid eye movement stage (8 +/- 8 vs. 17 +/- 8; P < 0.001). Clinical data and sleep characteristics were similar in PD with/without EDS. Of interest, patients treated with clonazepam (CLNZ) had lower EDS than those without CLNZ (ESS, 7.9 +/- 4.7 vs. 11.3 +/- 4.0; P = 0.03). These patients suffered less periodic leg movement during sleep (2.1 +/- 2.7 vs. 12.4 +/- 28; P = 0.04), which might explain the finding. No correlation was found between ESS, MSLT, and all other clinical features analyzed. In PD patients, according to the data obtained, severity of EDS does not depend on any specific clinical factor and the etiology is probably multifactorial. Paradoxically, PD patients treated with CLNZ were less sleepy than patients not treated with CLNZ.
    Movement Disorders 09/2006; 21(9):1432-8. · 4.56 Impact Factor
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    ABSTRACT: We studied the effect of quetiapine in drug induced psychosis (DIP) in Parkinson's disease (PD) patients with dementia (PDDEM) and without dementia (PDNODEM) in a 6-month open study. Thirty five consecutive PD patients with DIP (19 of them demented [DSMIV criteria]) were examined. Assessment included Mini-Mental State Examination (MMSE), UPDRS (motor part), Brief Psychiatric Rating Scale (BPRS), Clinical Global Improvement Scale (CGIS) and Hamilton test (for depression). Quetiapine was administered in a flexible dose 25-600 mg daily. Out of the 35 patients included in the study, 24 completed treatment with quetiapine (14 demented and 10 without dementia). Treatment was stopped in 11 patients (5 demented). Intention to treat patient (ITT) analysis did not show a significant quetiapine effect (BPRS), although in about 30% a good outcome was reported by the family (CGIS). Among the patients who completed the study (n = 24), in the PDNODEM group (n = 10) BPRS improved almost significantly (p = 0.06) while in the PDDEM group the BPRS did not change. According to the CGIS, a good improvement was observed in 50% of the PDDEM group (7/14) and 40% of the PDNODEM group (4/10). Motor features of PD patients worsened mildly (p = 0.05) in the PDDEM group. In this open trial, quetiapine was not beneficial in the ITT group using the BPRS, although families reported improvement in about 30% of patients (CGIS). Among patients who completed the study, quetiapine was more effective in the PDNODEM group. A double blind study with quetiapine is required.
    Journal of Neurology 03/2006; 253(2):171-5. · 3.58 Impact Factor
  • Parkinsonism & Related Disorders - PARKINSONISM RELAT DISORD. 01/2006; 12:30-30.
  • C. Klein, L. Polak, J. M. Rabey
    Clinical Neurophysiology - CLIN NEUROPHYSIOL. 01/2006; 117:126-127.
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    ABSTRACT: To evaluate the long-term outcome of quetiapine (QTP) use for drug-induced psychosis in Parkinson disease as assessed by the primary caregiver using the Clinical Global Impression Scale. Thirty-five patients (mean age+/-SD, 76.1+/-5.9 years; mean disease duration+/-SD, 10.3+/-5.3 years; 19 with dementia) were followed up over a 24-month period. At 6 months, 20 (57%) responded to QTP, of whom 11 (31%) maintained their improvement in the long term (for 24 months). Altogether, 15 patients (43%) responded to QTP in the long term (11 were still on treatment at 24 months, 3 stopped because of improvement and medication was no longer required, and 3 stopped because of financial reasons [one was responding positively by the time of stopping medication]). The medications of nonresponding patients (n=15) were switched to clozapine, with a positive response in 12 patients (80%). In long-term follow-up, 31% of parkinsonian patients with psychosis treated with QTP were still on QTP therapy at 24 months. For those failing to respond to QTP, clozapine was an effective alternative therapy.
    Clinical Neuropharmacology 01/2006; 29(4):215-9. · 1.82 Impact Factor
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    ABSTRACT: We studied medial dorsal superficial peroneal (MDSP) nerves in 52 patients with clinical evidence of mild chronic sensorimotor polyneuropathy and normal sural nerve responses, in order to assess the diagnostic sensitivity and usefulness of MDSP nerve testing in electrodiagnostic practice. To determine the effect of age on MDSP nerve parameters, 98 normal subjects were also examined. Electrodiagnostic evaluation involved studies of motor nerve conduction in tibial, peroneal, and median nerves; sensory nerve conduction in sural, MDSP, median, and radial nerves; tibial and peroneal nerve F waves; H reflexes from the soleus muscles; and needle electromyography of gastrocnemius and abductor hallucis muscles. Among the patients, 49% had low-amplitude sensory responses in MDSP nerves and 57% had either slowing of sensory conduction velocity or no sensory responses on proximal stimulation. MDSP nerve amplitude, tibial nerve motor velocity, and H reflexes were the most sensitive for detection of mild chronic symmetrical axonal sensorimotor polyneuropathy. MDSP nerve testing should be included in the routine electrodiagnostic evaluation of patients with suspected polyneuropathy and normal sural nerve responses.
    Muscle & Nerve 04/2005; 31(3):386-9. · 2.31 Impact Factor
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    ABSTRACT: Contradictory possible cardiovascular side effects of selegiline have been reported. Therefore, we studied the effect of acute administration of selegiline with levodopa (LD) compared with LD alone, on blood pressure, pulse and norepinephrine (NE) plasma levels, during an orthostatic test on chronically treated Parkinson's disease patients (PDpts) and controls. Twelve PDpts treated with LD (group D), 12 PDpts treated with selegiline and LD (group S) and eight volunteers (CTRL) underwent the orthostatic test. Patients repeated the test twice, before and after acute loading with 125 mg LD (group D) and 125 mg LD +5 mg selegiline (group S). Group S showed more episodes of postural hypotension (n = 10; two symptomatic) than group D (n = 4) and CTRL (n = 2), however not statistically significant. Plasma NE also rose significantly higher (P < 0.001) in group S. PD patients treated with selegiline showed more orthostatism and higher plasma NE after submission to the orthostatic test. These findings may be relevant to explain its deleterious effect.
    Acta Neurologica Scandinavica 02/2005; 111(2):89-94. · 2.47 Impact Factor
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    ABSTRACT: 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. Polysomnographic studies were performed in 11 patients with intracranial tumors (nine supra- and two infratentorial) before and after surgery. 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. 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.
    Acta Neurologica Scandinavica 01/2004; 109(1):56-60. · 2.47 Impact Factor
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    ABSTRACT: Eighteen adult patients with serologically confirmed West Nile virus (WNV)-associated meningitis or meningoencephalitis were admitted to our hospital during the 2000 West Nile fever outbreak in Israel. Thirteen of the patients had a more severe and prolonged clinical course, and an electroencephalogram (EEG) was, therefore, requested. A specific EEG pattern was seen in 8 patients, consisting of generalized slowing, which was more prominent over the anterior regions. Generalized slowing that was prominent over the temporal area was seen in 2 patients, and intermittent slowing over the temporal region was seen in 1 patient. Two patients had normal EEG findings. We suggest that WNV meningoencephalitis should be considered in the differential diagnosis of meningitis or meningoencephalitis with a prolonged clinical course and anteriorly predominant slowing on an EEG.
    Clinical Infectious Diseases 01/2004; 37(11):1573-8. · 9.37 Impact Factor
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    ABSTRACT: Dizziness and vertigo can be a complaint in various psychiatric conditions where it usually constitutes only one of the features of the syndrome. Lately, a somatoform disorder characterized by almost mono-symptomatic dizziness and unsteadiness has been described. Since phobic postural vertigo usually presents without anxiety or other psychological symptomatology, patients with this condition seek help at neurologic and otolaryngologic clinics where they are often misdiagnosed as suffering from organic vertigo. To present the clinical features of 55 consecutive patients diagnosed with phobic postural vertigo at our clinic during 1998-2002. We conducted a retrospective review of patients' medical records and report two typical cases for illustration. The patients presented with complaints of unsteadiness with or without dizziness, and attacks of sudden veering that caused them to grasp for support. Accompanying anxiety was admitted by only 5% and vegetative symptoms were reported in 18%. In 16% the symptoms resulted in avoidance behavior. A stressful life event or an unrelated somatic disease triggered the onset of PPV in 35% of patients, whereas a vestibular insult preceded the symptoms in 13%. The mean duration of symptoms was 26.7 +/- 39.1 months (range 0.5-20 years). In 72% of patients the symptoms resolved after the psychological mechanism of their symptoms was explained to them; 24% improved with antidepressant treatment (selective serotonin reuptake inhibitors or tricyclic antidepressants), and only in 4% did the symptoms persist. Since PPV is a frequently encountered diagnosis at some specialized dizziness clinics, familiarity with this entity resulting in early diagnosis can avoid unnecessary examinations and lead to effective treatment.
    The Israel Medical Association journal: IMAJ 11/2003; 5(10):720-3. · 0.98 Impact Factor
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    ABSTRACT: Although psychiatric disturbances have been reported in chronic vestibular disorders, little is known about the psychological impact of an acute vertigo attack. We conducted a comparative questionnaire study in 30 patients with a first attack of vestibular dysfunction and in 35 patients with a nonvestibular neurologic deficit of acute onset. Patients with vertigo reported more anxiety than patients with nonvestibular neurologic deficits (P = 0.002), despite the fact that premorbid anxiety was similar in both groups (P = 0.5). No difference in anxiety levels was found between vertigo patients who vomited and those who were free of vegetative symptoms (P = 0.97). Vertigo patients felt more disabled than nonvertigo patients (P = 0.06), irrespective of the objective restrictions caused by the disease. The rate of depression did not differ between the groups of patients (P = 0.09). Patients with acute vertigo experience extreme anxiety, and this contributes to their feeling of disproportionate disability. The reason for emotional disturbances in vestibular dysfunction is probably the result of physiological connections between the vestibular and limbic system and deserves further neuroanatomic investigation.
    Otolaryngology Head and Neck Surgery 07/2003; 128(6):829-34. · 1.73 Impact Factor
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    ABSTRACT: Centrally acting cholinesterase inhibitors (ChEIs) improve cognitive functions in Alzheimer's disease (AD) and other forms of dementia. Evaluation of treatment efficacy is based mainly on subjective assessment methods such as standardized neuropsychological tests. Therefore, an additional objective tool for the evaluation of drug response would be most helpful.Thirty-two patients suffering from dementia of several etiologies were treated with ChEIs (tacrine 19, donepezil 5, rivastigmine 8). Cognitive response was assessed pre ChEIs initiation (baseline) and after 26 weeks, as optimal tolerated doses were achieved and maintained (endpoint). Evaluation included repeated measurements of Mini Mental State Examination (MMSE), Alzheimer's disease assessment scale cognitive part (ADAS-cog) and P300. For statistical analysis we used ANOVA with repeated measures and Pearson correlation coefficient. Results demonstrated improvement of mean ADAS-cog by 2.0 points (from 29.4, n = 31 to 27.4, n = 29; p = 0.08) while MMSE remained almost unchanged (20.1, n = 29 to 19.8, n = 28). Mean P300 latency reduced significantly by 24 ms (from 383 +/- 7.9 msec, n = 32 to 359 +/- 7 msec, n = 32; p = 0.0001). However mean amplitudes did not change significantly from baseline to endpoint (13.5 +/- 6.2, n = 31 to 12.8 +/- 6.1, n = 31). Significant correlations were found between mean ADAS-cog and mean P300 latency at baseline and end-point (R = 0.485 p = 0.019, R = 0.626 p = 0.001 respectively, n = 23) and between mean MMSE and P300 latency at baseline and endpoint (R = -0.420 p = 0.046, R = -0.703 p < 0.001 respectively, n = 23). Our data suggests that P300 is a reliable instrument for assessment of cognitive response to ChEIs in demented patients.
    Journal of Neural Transmission 06/2003; 110(6):659-69. · 3.05 Impact Factor

Publication Stats

545 Citations
128.46 Total Impact Points

Institutions

  • 1998–2009
    • Tel Aviv University
      • Department of Neurology
      Tel Aviv, Tel Aviv, Israel
  • 1989–2009
    • Assaf Harofeh Medical Center
      Ayun Kara, Central District, Israel