N Karandreas

Harokopion University of Athens, Athínai, Attica, Greece

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Publications (47)100.96 Total impact

  • [Show abstract] [Hide abstract]
    ABSTRACT: The authors have observed that in healthy people, the Ulnar wrist-to-first dorsal interosseous distal motor latency does not differ significantly compared with median wrist-to-abductor pollicis brevis distal motor latency. The aim of our study was to investigate whether the difference between these two latencies can be used as a screening tool for diagnosing carpal tunnel syndrome and how this technique compares with other established techniques. The study was set up as a prospective observational study. As gold standard for the clinical diagnosis of carpal tunnel syndrome, the authors used the opinion of two neurologists who independently examined the patients. A third neurologist, also independently, performed the electrophysiological study. Eighty-four subjects, 42 patients and 42 age- and sex-matched controls, participated in the study. Among all subjects using a receiver operating characteristic curve analysis, the area under the curve was 0.924 (95% CI, 0.857-0.991; SE, 0.034; P < 0.001). To detect carpal tunnel syndrome, at a cutoff score of equal to or greater than 0.575 milliseconds, our technique showed a sensitivity of 91%, a specificity of 93%, a positive predictive value of 93%, and a negative predictive value of 91%. Compared with other "classical" techniques, our technique showed better area under the receiver operating characteristic curve and better Youden index. The median wrist-to-abductor pollicis brevis motor latency minus ulnar wrist-to-first dorsal interosseous motor latency may be used as a novel rapid screening tool of patients suffering from carpal tunnel syndrome.
    Journal of clinical neurophysiology: official publication of the American Electroencephalographic Society 08/2015; 32(4):375-379. DOI:10.1097/WNP.0000000000000180 · 1.43 Impact Factor
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    ABSTRACT: There has been limited information from population studies regarding the overall frequency of the common 1.5-Mb 17p11.2 deletion and even scarcer data regarding the overall frequency of PMP22 micromutations in patients with a clinical suspicion of HNPP. We have analyzed 100 consecutive Greek patients referred for HNPP genetic testing over a 15-year period to our Neurogenetics Unit in Athens, a reference center for all regions of Greece. All patients were screened for the 1.5-Mb deletion and a selected subgroup of deletion-negative patients for PMP22 micromutations. Mutation-positive and -negative patients were compared for various clinical parameters. In total, 54 mutation-positive patients were identified. In index cases, the deletion frequency was 47.8% and the PMP22 micromutation frequency 2.2%. Within mutation-positive patients the common deletion represented 95.7% and PMP22 micromutations 4.3% of cases. Two previously reported PMP22 micromutations (c.364_365delCC and c.79-2A>G) were detected. HNPP index cases had a 2.8 to 1 male-to-female ratio, similar to mutation-negative patients. A typical phenotype (recurrent or isolated palsies) was present in 82.4% of symptomatic HNPP cases, significantly higher than mutation-negative patients. Sensitivity of proposed electrophysiological diagnostic criteria for HNPP was calculated at 95.7% and specificity at 80.5%. In conclusion, the common HNPP deletion accounts for ~ 50% and PMP22 micromutations for ~ 2% of cases in a large consecutive cohort of patients with suspected HNPP. The mutational and phenotypic spectrum of HNPP is similar in the Greek population compared to other populations. Proposed electrophysiological diagnostic criteria perform satisfactorily in every day clinical practice. This article is protected by copyright. All rights reserved.
    Journal of the Peripheral Nervous System 06/2015; 20(2). DOI:10.1111/jns.12125 · 2.76 Impact Factor
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    P Kokotis · G K Papadimas · V Zouvelou · T Zambelis · P Manta · N Karandreas
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    ABSTRACT: Purpose/Aim of the study: An increased serum level of creatine kinase in asymptomatic individuals is a diagnostic challenge, as it may be associated with either physiological conditions, such as exercise or even signal an ominous neuromuscular disease at a presymptomatic stage. The electromyogram and the muscle biopsy play a key role in the evaluation of asymptomatic hyperckemia. The objective of this study was to investigate asymptomatic individuals with increased creatine kinase levels. We comparatively studied electromyogram, quantitative electromyogram and muscle biopsy in asymptomatic clinically normal individuals with repeatedly increased creatine kinase levels. Conventional electromyogram was abnormal in 76% of patients, while quantitative electromyogram showed abnormal results in 88.9%. Muscle biopsy was diagnostic in 28%, one patient had neurogenic findings, 40% showed non specific changes and 28% had normal results. Electromyogram and especially quantitative electromyogram are highly sensitive in detecting subclinical neuromuscular diseases, whereas muscle biopsy may better contribute in the final diagnosis. No strong correlations were found between histological abnormalities and electrophysiological data, but further research is needed.
    The International journal of neuroscience 05/2015; DOI:10.3109/00207454.2015.1038534 · 1.52 Impact Factor
  • Th Zambelis · V Pappas · P Kokotis · V Zouvelou · N Karandreas
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    ABSTRACT: The aim of this study was the diagnosis of patients with isolated ocular manifestations (ptosis and/or diplopia) referred for electrophysiological evaluation to the electrodiagnostic laboratory of a University Neurological Department. Examination was performed either in inpatient status or in outpatient basis. We analyzed the clinical, electrophysiological and other laboratory data in 79 subjects. Myasthenia gravis (MG) was diagnosed in 38 %, 45.6 % in other diseases (Graves disease, blepharospasm, IIId cranial verve palsy, multiple sclerosis, stroke, etc.), while in 16.5 %, the cause remained unidentified. Symptoms fluctuation was significantly more frequent in the myasthenic patients, compared to patients with other diseases. The presence of both diplopia and ptosis are more likely due to MG rather than other pathology.
    03/2015; DOI:10.1007/s13760-015-0460-x
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    ABSTRACT: The aim of this study was to compare Bangladeshi immigrants with diabetes to native Greeks with diabetes and to distinguish the different risk factors for polyneuropathy in the two ethnic groups. Subjects were recruited from the outpatient diabetic clinic of a general hospital.One hundred and eleven Bangladeshi immigrants (97 men and 14 women of mean age 47 years) and one hundred and one native Greeks (82 men and 19 women of mean age 49 years) were included in the study. Sex, mean age, age at diabetes diagnosis, and diabetes duration did not differ between the two groups. Polyneuropathy was diagnosed in 53 (48%) Bangladeshi and in 59 (58%) Greek patients (p = 0.12). Large fiber neuropathy was less prevalent among Bangladeshis (18%) than in Greeks (53%) (p < 0.01). Small fiber neuropathy on the contrary were more frequent in Bangladeshis (18% vs 7%) (p < 0.02).Regarding the risk factors for polyneuropathy, Greek patients were taller, with higher BMI, and smoked more cigarettes (p < 0.001). They were also treated with more anti-lipid and antihypertensive agents.The higher percentage of SFN in Bangladeshi was mainly a result of the significantly greater incidence of erectile dysfunction (ED) in their group (68 Bangladeshi vs 38 Greek men). It is well known that there are many causes of ED aside from SFN which were not evaluated in this study. Thus this conclusion should be taken with caution.
    Journal of the Peripheral Nervous System 01/2015; 19(4). DOI:10.1111/jns.12101 · 2.76 Impact Factor
  • S. Methenitis · G. Terzis · E. Bakola · N. Karandreas
    Clinical Neurophysiology 06/2014; 125:S274. DOI:10.1016/S1388-2457(14)50898-X · 3.10 Impact Factor
  • T. Zambelis · E. Bakola · V. Zouvelou · P. Kokotis · N. Karandreas
    Clinical Neurophysiology 06/2014; 125:S300. DOI:10.1016/S1388-2457(14)50984-4 · 3.10 Impact Factor
  • A. Papagianni · P. Kokotis · T. Zambelis · N. Karandreas
    Clinical Neurophysiology 06/2014; 125:S288-S289. DOI:10.1016/S1388-2457(14)50946-7 · 3.10 Impact Factor
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    ABSTRACT: Background The Douleur Neuropathique 4 questionnaire (DN4) was developed by the French Neuropathic Pain Group and is a simple and objective tool, primarily designed to screen for neuropathic pain. The aim of our study is to validate the DN4 in the Greek language.Methods The study was set up as a prospective observational study. Two pain specialists independently examined patients and diagnosed them with neuropathic, nociceptive, or mixed pain, according to the International Association for the Study of Pain (IASP) definitions. A third and a fourth physician administered the DN4 questionnaire to the patients.ResultsOut of the 237 patients who met our inclusion criteria and had identical diagnoses regarding the type of pain, 123 were diagnosed with neuropathic, 59 with nociceptive, and 55 with mixed pain. Among patients with identical diagnoses of neuropathic or nociceptive pain, using a receiver operating characteristic (ROC) curve analysis, the area under the curve (AUC) was 0.92. A cutoff point of equal or greater than 4 resulted in a sensitivity of 93% and a specificity of 78%. Among patients suffering from pain with neuropathic element (neuropathic or mixed pain) or pain with no neuropathic element (nociceptive pain), using a ROC curve analysis, the AUC was 0.89. A cutoff point of equal or greater than 4 resulted in a sensitivity of 89% and a specificity of 78%.Conclusion The Greek version of DN4 is a valid tool for discriminating between neuropathic and nociceptive pain conditions in daily practice.
    Pain Practice 04/2014; 15(7). DOI:10.1111/papr.12221 · 2.36 Impact Factor
  • 3rd Congress of Biochemistry and Exercise Physiology of Hellenic Society of Biochemistry and Physiology of Exercise, Athens, Greece,; 11/2013
  • V. Zouvelou · T. Zambelis · N. Karandreas
    European geriatric medicine 01/2013; 5(1). DOI:10.1016/j.eurger.2013.11.002 · 0.73 Impact Factor
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    ABSTRACT: OBJECTIVE: To investigate the underlying mechanisms of polyneuropathy induced by HIV infection or antiretroviral drugs. METHODS: We tested 100 HIV patients (59 with AIDS). Ninety-three patients received antiretroviral drugs. Forty-four were treated with neurotoxic compounds (ddI, ddC, d4T). Nerve conduction velocities and the sympathetic skin response (SSR) in palms and soles were measured in all patients. In skin biopsies (ankle and thigh), the intraepidermal nerve fiber density (IENFD) and the number of epidermal fibers without contact to the basal membrane (fragments) were quantified using PGP9.5 staining. RESULTS: Severity of the disease (CD4+count) correlated to conduction velocities of peroneal (p<0.01, Spearmans rank correlation), sural (p<0.01) and median nerves (p<0.05/p<0.001, sensory/motor). In contrast, the duration of neurotoxic treatment did not impair conduction velocities (p>0.3) but correlated to reduced IENFD in the ankle (r=-0.24, p<0.05). Despite their reduced IENFD, patients with long neurotoxic treatment had a high number of fragments irrespective of their CD4+count. CONCLUSIONS: Neurotoxic treatment appears to primarily impair thin fiber conduction, whereas HIV neuropathy is linked to large fiber impairment and reduction of fragments of nerve fibers. SIGNIFICANCE: These findings emphasize the differential pattern of polyneuropathy in HIV patients caused by the infection or induced by antiretroviral treatment.
    Clinical neurophysiology: official journal of the International Federation of Clinical Neurophysiology 07/2012; 124(1). DOI:10.1016/j.clinph.2012.05.022 · 3.10 Impact Factor
  • E Andreadou · V Zouvelou · N Karandreas · C Kilidireas
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    ABSTRACT: Clinical involvement of the peripheral nervous system in the calcinosis cutis, raynaud's phenomenon, esophageal dismotility, sclerodactyly and telangiectasia (CREST) variant of systemic sclerosis occurs infrequently and is characterized by axonal degeneration due to necrotizing vasculitis. We report a female patient with a known history of CREST syndrome, which developed a slowly progressive, distal symmetric demyelinating sensorimotor polyneuropathy (PN), with tremor and ataxia as prominent features, compatible with anti-myelin associated glycoprotein (MAG) PN. The diagnosis of PN was established by the presence of monoclonal immunoglobulin M anti-MAG antibodies (Thin-Layer Chromatography, Western Blot and enzyme-linked immunoabsorbent assay). Given the evidence that in CREST activation of T-helper cells is observed and that anti-MAG antibodies, despite the fact that they are T-cell-independent, may be influenced by an increase in T-helper function, the coexistence of these two rare autoimmune disorders in the same patient may not be incidental but related to the underlying immunological mechanisms involved.
    Journal of Postgraduate Medicine 01/2012; 58(1):57-9. DOI:10.4103/0022-3859.93254 · 0.86 Impact Factor
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    Th. Zambelis · P Kokotis · N Karandreas
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    ABSTRACT: To assess the utility of repetitive nerve stimulation (RNS) in facial and hypothenar muscles in the clinical groups of myasthenia gravis (MG). We performed RNS study in the orbicularis oculi (O.O.), nasalis and abductor digiti quinti (ADQ) in 115 consecutive myasthenic patients and classified them according to the classifications of the Myasthenia Gravis Foundation of America. Patients were classified into three groups: group 1, group 2 (IIa, IIIa and IVa) and group 3 (IIb, IIIb and IVb). RNS was abnormal in 95 patients (82.6%): 78.3% in the O.O., 66.1% in the nasalis and 19.1% in the ADQ. Both facial muscles were statistically more sensitive than the ADQ in all groups of patients. RNS in the O.O. was more frequently abnormal than in the nasalis only in group 1. Sensitivity to acetylcholine antibodies in myasthenic patients was 84%. Acetylcholine receptor (AChR) and muscle-specific tyrosine kinase antibodies were present in 96.7% of the patients with abnormal RNS in both facial muscles. Single-fiber electromyogram (SFEMG) was abnormal in 91.3% of the tested patients. One of the three tests used for the diagnosis of MG (AChR antibodies, SFEMG, RNS) was abnormal in 99.1% of the patients. O.O. is the most sensitive muscle in all groups of MG followed by nasalis, while the ADQ is the muscle with the lowest sensitivity. Facial muscles, especially the O.O., should be the first to be tested in MG. The negativity of all tests (RNS, AChR antibodies, SFEMG) should question the diagnosis of MG, even in the presence of symptoms consistent with MG.
    European Neurology 03/2011; 65(4):203-7. DOI:10.1159/000324915 · 1.36 Impact Factor
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    ABSTRACT: The purpose of this study was to investigate the clinical, electrophysiological and pathological features of Churg Strauss syndrome (CSS) neuropathy. Biopsies were selected from over 700 sural nerve biopsies. The diagnosis of vasculitis was based on established clinicopathological criteria. Complete laboratory, clinical, electrophysiological and pathological studies were performed in all cases. Nerve biopsies of 9 patients were diagnosed as Churg-Strauss syndrome. The pathological features were vasculitis with predominant axonal degeneration and a varying pattern of myelinated fiber loss. The vasculitic changes were found mainly in small epineural blood vessels. Mononeuritis multiplex and distal symmetrical and asymmetrical sensorimotor neuropathy, were equally frequent. We conclude that, Churg-Strauss syndrome complicated frequently with polyneuropathy, and as remission depends on immunosuppressive therapy, it is important to recognize it in the early stage. The diagnosis of polyneuropathy is based on clinical and electrophysiologic studies, but precise histology, immunolohistochemistry and morphometric study of the peripheral nerve biopsy may be decisive in establishing the diagnosis.
    Clinical neuropathology 01/2011; 30(1):11-7. DOI:10.5414/NPP30011 · 1.53 Impact Factor
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    ABSTRACT: Mirror movements (MMs) are unintended and unnecessary movements accompanying voluntary activity in homologous muscles on the opposite side of the body, particularly in distal arm muscles. Congenital MMs may be sporadic or familial. Several mechanisms have been proposed to explain persistent congenital MMs. Hypothesis 1 assumes the existence of an ipsilateral corticospinal pathway, and Hypothesis 2 the activation of both motor cortices. We report a new case of congenital mirror movements in a healthy woman. Electromyographic recordings and focal transcranial magnetic stimulation (TMS) were used for neurophysiological evaluation. Voluntary contraction of either abductor pollicis brevis (APB) elicited mirror activation of the other APB. Focal TMS of either M1 elicited motor evoked potential (MEP) of normal latency and amplitude in both resting APB. TMS of the left cortex upon maximal contraction of the right APB and mirror contraction of the left APB produced interhemispheric inhibition (IHI) in the former and silent period (SP) in the later. The electrophysiological evaluation using transcranial magnetic stimulation provides evidence of the concurrent action of both mechanisms in this patient. The combination of more than one hypothesis could be more appropriate for understanding the underlying mechanism in some MM cases.
    Clinical neurology and neurosurgery 11/2010; 112(9):824-8. DOI:10.1016/j.clineuro.2010.06.016 · 1.13 Impact Factor
  • Clinical Neurophysiology 10/2010; 121. DOI:10.1016/S1388-2457(10)60581-0 · 3.10 Impact Factor
  • Clinical Neurophysiology 10/2010; 121. DOI:10.1016/S1388-2457(10)60747-X · 3.10 Impact Factor
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    P Kokotis · D Mandellos · A Papagianni · N Karandreas
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    ABSTRACT: Age and height influence on sural sensory nerve action potential (SNAP) have been studied separately. Our aim was to develop an equation for predicting the lower normal limits as a function of both these factors. One hundred fifty-eight healthy volunteers, 63 male, with mean age 45.8 and mean height 167.3 without symptoms or signs of peripheral neuropathy participated in the study. The sural SNAP was recorded at the level of the ankle joint, just posterior to the lateral malleolus, using surface electrodes. Antidromic supramaximal stimulation was performed 13 cm proximally at the posterior midcalf. The mean sural SNAP amplitude was 19.9+/-6.89 microV. Pearson linear correlation showed a negative correlation of the SNAP amplitude with age (R=-0.22, p=0.005) and height (R=-0.19, p=0.03). The multiple linear regression model was applied for both parameters of age and height with SNAP amplitude as the dependent parameter, producing the following equation: SNAP amplitude=62.45-0.1447 x Age-0.2147 x Height. Using our normal data, the computed lower limits of the 95% prediction interval for the sural SNAP amplitude of an individual subject, depending on his age and height, were calculated. The individualized normal values provided by our equation are essential for the correct interpretation of sural nerve studies.
    Clinical neurophysiology: official journal of the International Federation of Clinical Neurophysiology 04/2010; 121(4):561-3. DOI:10.1016/j.clinph.2009.11.079 · 3.10 Impact Factor
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    Thomas Zambelis · Georgios Tsivgoulis · Nikolaos Karandreas
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    ABSTRACT: The investigation of the association between known risk factors and laterality in patients with carpal tunnel syndrome (CTS). Patients and 130 consecutive subjects with CTS only, or mainly, in the left hand were compared with 130 consecutive subjects with CTS only, or mainly, in the right hand. The following parameters were recorded: age, sex, job, handedness, hand mainly used in daily activities, BMI, diabetes mellitus, thyroid dysfunction, wrist trauma and connective tissue diseases. A left dominant hand was independently associated with 13-fold higher odds for left-hand CTS, while a right dominant hand had 5-fold higher odds for right-hand CTS. Right-hand CTS was more frequent in younger subjects and females. Older age, higher BMI and diabetes mellitus were more prevalent in patients with bilateral CTS. Age and BMI were independently associated with bilateral CTS.
    European Neurology 12/2009; 63(1):43-7. DOI:10.1159/000268165 · 1.36 Impact Factor

Publication Stats

288 Citations
100.96 Total Impact Points


  • 2008–2015
    • Harokopion University of Athens
      Athínai, Attica, Greece
    • Κωνσταντοπούλειο νοσοκομείο Νέας Ιωνίας (Η Αγία Όλγα)
      Athínai, Attica, Greece
  • 2005–2015
    • Eginition Hospital Athens
      Athínai, Attica, Greece
  • 2012
    • National Technical University of Athens
      Athínai, Attica, Greece