Colin Klein

Tel Aviv University, Tell Afif, Tel Aviv, Israel

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Publications (20)57.73 Total impact

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    ABSTRACT: Hospitalization is a significant factor contributing to health care costs related to management of Parkinson’s disease (PD) patients. We reviewed reasons for admission of PD patients to our Neurological Department over a 6-year period. Thereafter, we applied an “open door” policy to try to diminish the number of hospitalizations. Case records including patient data, disease duration, staging, reasons for admission, and motor, mental and general medical status of PD patients admitted to the Neurology Department over a 6-year period were reviewed. Out of 1,920 admissions, 143 were PD patients. All PD admissions were through the emergency department (non-elective). Motor complications were the reason for admission in 37%, psychosis in 24%, general medical problems in 14%, and a combination of motor and psychiatric in 25%. Drug-induced psychosis was the most significant cause of repeated and prolonged admissions (29% of patients). As motor and psychiatric complications are the commonest causes for admission, improved community-based care to “fine tune” medication appeared to be a priority. After analyzing our results, we instituted an “open door” policy, where patients are free to come to the Parkinson’s clinic without appointment. This policy should improve control of PD symptoms and diminish hospitalizations.
    No preview · Article · Nov 2009 · Journal of Neural Transmission
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    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.
    No preview · Article · Oct 2009 · Journal of Neuroscience Methods
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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.
    Full-text · Article · Feb 2008 · The Israel Medical Association journal: IMAJ
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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.
    Preview · Article · Jan 2008 · Muscle & Nerve
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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.
    No preview · Article · Nov 2007 · Journal of Emergency Medicine
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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.
    No preview · Article · Feb 2007 · Movement Disorders
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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.
    No preview · Article · Sep 2006 · Movement Disorders
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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.
    No preview · Article · Sep 2006 · Movement Disorders
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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.
    No preview · Article · Jul 2006 · Clinical Neuropharmacology
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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.
    No preview · Article · Mar 2005 · Muscle & Nerve
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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.
    Preview · Article · Nov 2003 · The Israel Medical Association journal: IMAJ
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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.
    No preview · Article · Jul 2003 · Otolaryngology Head and Neck Surgery
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    ABSTRACT: A 39-year-old old Jewish woman of Algerian origin developed a rapidly progressive neurocognitive disorder characterized by asymmetric rigidity, spasticity with bilateral Babinski's sign, bradykinesia, altered speech that progressed to mutism, and severe bradyphrenia. She partially responded to levodopa. The family history revealed 4 affected first-degree relatives (3 had already died). Genetic studies carried out in the proband and her living affected sister showed a P301S mutation in chromosome 17.
    No preview · Article · Jun 2003 · Movement Disorders
  • Colin Klein · Jacob Gordon · Lea Pollak · J Martin Rabey
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    ABSTRACT: The objective of this study was to monitor the long-term effect of clozapine administered to Parkinson's disease (PD) patients with psychosis. Confusion, visual hallucinations, and psychosis are major dose-limiting factors for long-term dopaminergic management of PD. Classic neuroleptic agents exacerbate the motor symptoms of the disease. For this reason, the introduction of atypical antipsychotic drugs has been a major advancement for the management of psychosis in patients with PD. Of them, clozapine is one of the most effective. Thirty-two patients (mean age, 73 years; mean disease duration, 12.2 years) with PD and psychosis (DSM-IV), 14 of them with dementia (DSM-IV), were followed for 5 years with periodic clinical evaluation, Mini Mental State Examination (MMSE), and Parkinsonian Psychosis Rating Scale (PPRS) administered before and following the study (at least once in 6 months). Periodic blood count was performed for tracking neutropenia. Nineteen patients (8 with dementia) have continued to receive clozapine (mean daily dose, 50 mg). Thirteen patients stopped medication: 9 because symptoms improved and did not return after weaning off clozapine; 3 patients because of somnolence; and 1 because of personal reasons. The average duration of treatment in those in whom medication was stopped was 8.5 months (range, 1-24 months). No correlation was found between age, sex, duration, and severity of disease (Yahr scoring), the presence of dementia, and the response to clozapine. Also, the PPRS scoring did not influence clozapine response. No case of neutropenia was found. According to the experience accumulated and the results of the present study, the authors believe clozapine is the best therapeutic choice currently available for the management of psychosis in patients with PD.
    No preview · Article · Jan 2003 · Clinical Neuropharmacology
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    ABSTRACT: Electrical stimulus, with duration starting at 0.1 ms and gradually increased to 1.0 ms, was used for eliciting the H reflex in 14 normal subjects and 19 patients with Parkinson's disease (PD). In 71.1% of normal subjects and in 13.2% of PD patients the H reflex to M response threshold ratio (H/M TR) was <1 and the H reflex was obtained before the M response for all duration stimuli. For all stimulus durations a significant difference between the H/M TR in normal subjects and PD patients was found (t test 0.002-0.007). The duration effect was found to be highly significant-H/M TR for short stimulus duration was greater than for long stimulus durations (p<0.001). The optimal stimulus duration for evaluating H reflex behavior in PD patient was 0.2 ms. These very significant differences in behavior of the H reflex in PD patients could be used as another parameter in the assessment of extrapyramidal rigidity in PD patients.
    No preview · Article · Dec 2002 · Parkinsonism & Related Disorders
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    ABSTRACT: The Short Parkinson's Evaluation Scale has been compiled and validated previously (Clinical Neuropharmacology, 1997). In the present study, we have assessed and compared the motor scoring of the Unified Parkinson's Disease Rating Scale and the Short Parkinson's Evaluation Scale in 23 patients (mean age, 61.8 years) with Parkinson's disease. Patients were 12 hours off medication at the beginning of the series. They were then given levodopa, 125 mg and 250 mg, on different days and were evaluated each 30 minutes for 2 hours. In addition, patients' motor skills (finger tapping and walking velocity) were measured at each time. Analysis of variance with repeated measures was applied. The results presented show that both scales have the same ability to measure levodopa-dose effect within time. In addition, Spearman's correlation coefficients showed a negative correlation between finger tapping and upper-limb impairment and a positive correlation between walking velocity and lower-limb impairment in both scales. In summary, the present results suggest that Short Parkinson's Evaluation Scale is a useful tool in assessing the effect of medication, having the advantage of being easier and quicker.
    No preview · Article · Mar 2002 · Clinical Neuropharmacology
  • Mark Kushnir · Colin Klein · Jose Martin Rabey
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    ABSTRACT: The H reflex was elicited in 21 normal subjects, 48 patients with Parkinson's disease (PD) and 22 patients with pyramidal and extrapyramidal signs combined (PESC). In most normal subjects (90.5%), in 29.2% of PD patients and 54.5% of patient with PESC the threshold for sensory fibers was lower than for motor fibers, and the H reflex was obtained before the M response for all duration stimuli in both legs. In 9.5% of normal subjects, 39.6% of PD patients with mild and moderate rigidity (according to the motor part of UPDRS) and 31.8% of patients with PESC, the threshold for the H reflex and M response was the same or the M response threshold was lower in at least one of the legs for short stimulus duration (0.1-0.2 ms). In 31.2% of PD patients (most of them with severe rigidity) and 13.7% of patients with PESC, the threshold for M response was lower for all stimulus duration in at least one of the legs, and it was obtained before H reflex. These very significant differences in behavior of the H reflex in PD patients (Fisher exact test, p<0.0001) that almost disappear in patients with PESC, could be possibly explained by changes in agonist-antagonist inhibition.
    No preview · Article · May 2001 · Journal of the Neurological Sciences
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    ABSTRACT: 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.
    No preview · Article · Jul 1998 · Movement Disorders
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    ABSTRACT: Computerized EEG frequency analysis was performed in 18 patients with peripheral vestibular dysfunction (PVD), 17 patients with central vestibular dysfunction (CVD) and 22 aged matched controls. Increase in the relative theta activity in the centrotemporal region was found in patients with PVD. The decrease of centroparietal beta activity in both groups of patients, as compared to controls, did not reach statistical significance. We conclude that quantified EEG may be a sensitive method to show changes of cortical electrical activity in patients with vertigo, reflecting the imbalance in afferent vestibular input to the cortex.
    No preview · Article · Mar 1998 · International Journal of Neuroscience
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    ABSTRACT: We reviewed 7 cases with posterior fossa structural abnormalities (3 tumors, 2 megacisterna magna and 2 Dandy-Walker syndrome) presenting with neuropsychiatric symptomatology. Derangement in the balance of dopamine, serotonin and noradrenergic networks has been implicated in the pathogenesis of schizophrenia, affective and even personality disorders. Disruption of the cerebellar output to mesial dopaminergic areas, locus coeruleus and raphe nuclei, or deafferentation of the thalamolimbic circuits by a cerebellar lesion may lead to behavioral changes. Seven patients (pts) (comprising 4 men and 3 women with mean age 22 years) were diagnosed as suffering from psychosis (2 pts), major depression (1 pt), personality disorders (2 pts) and somatoform disorders (2 pts) (DSM-IV criteria). Brain CT scan (7 pts) and MRI (4 pts) revealed tumors of the posterior fossa (2 pts), megacisterna magna (2 pts) and Dandy-Walker variant (2 pts). In one patient a IVth ventricle tumor was removed in childhood.
    No preview · Article · Dec 1996 · International Journal of Neuroscience

Publication Stats

478 Citations
57.73 Total Impact Points

Institutions

  • 1998-2009
    • Tel Aviv University
      • • Department of Neurology
      • • Sackler Faculty of Medicine
      Tell Afif, Tel Aviv, Israel
  • 1996-2008
    • Assaf Harofeh Medical Center
      Ayun Kara, Central District, Israel