Derya Kaynak

Istanbul University, İstanbul, Istanbul, Turkey

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Publications (11)27.22 Total impact

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    ABSTRACT: Considering the association of sleep disturbance and fatigue in multiple sclerosis (MS), we investigated the presence of sleep disturbances that may be related to fatigue by using objective and subjective measures. We included 27 MS patients with fatigue, 10 MS patients without fatigue and 13 controls. The Pittsburgh sleep quality index score showed significant differences between patient groups and controls. Beck depression inventory scores were significantly higher in fatigued than non-fatigued patients. Comparison of patient groups and controls revealed significant differences for time in bed, sleep efficiency index, sleep continuity index, wake time after sleep onset, total arousal index and periodic limb movement arousal index. Our study confirms that MS causes sleep fragmentation in terms of both macro and microstructure. Fatigue in MS could be partially explained by disruption of sleep microstructure, poor subjective sleep quality and depression.
    European Journal of Neurology 01/2007; 13(12):1333-9. · 4.16 Impact Factor
  • G. Benbir, H. Kaynak, D. Kaynak
    Sleep Medicine - SLEEP MED. 01/2007; 8.
  • G. Benbir, D. Kaynak, H. Kaynak
    Sleep Medicine - SLEEP MED. 01/2007; 8.
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    ABSTRACT: In 2003, the EFNS Task Force was set up for putting forth guidelines for the management of the Restless Legs Syndrome (RLS) and the Periodic Limb Movement Disorder (PLMD). After determining the objectives for management and the search strategy for primary and secondary RLS and for PLMD, a review of the scientific literature up to 2004 was performed for the drug classes and interventions employed in treatment (drugs acting on the adrenoreceptor, antiepileptic drugs, benzodiazepines/hypnotics, dopaminergic agents, opioids, other treatments). Previous guidelines were consulted. All trials were analysed according to class of evidence, and recommendations formed according to the 2004 EFNS criteria for rating. Dopaminergic agents came out as having the best evidence for efficacy in primary RLS. Reported adverse events were usually mild and reversible; augmentation was a feature with dopaminergic agents. No controlled trials were available for RLS in children and for RLS during pregnancy. The following level A recommendations can be offered: for primary RLS, cabergoline, gabapentin, pergolide, ropinirole, levodopa and rotigotine by transdermal delivery (the latter two for short-term use) are effective in relieving the symptoms. Transdermal oestradiol is ineffective for PLMD.
    European Journal of Neurology 11/2006; 13(10):1049-65. · 4.16 Impact Factor
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    ABSTRACT: Nocturia is a common complaint in sleep-disordered breathing (SDB), but there is no study demonstrating the prevalence and frequency of nocturnal urination in a large number of SDB patients. To determine the prevalence and frequency of nocturnal urination among patients with SDB of different severities and to discover the factors related to nocturia. A retrospective chart review was conducted among 1970 SDB patients. Nocturia was assessed using a standard questionnaire. Four groups of SDB patients were compared with regard to frequency of nocturnal urination and additional demographic, clinical, and polysomnographic (PSG) variables, by analysis of variance (ANOVA) with Tukey's honest significant difference (HSD) post-hoc comparisons. Partial correlation analysis was performed to detect the relationships between frequency of nocturnal urination and PSG and demographic variables. Logistic regression analysis was employed to examine the independent predictors of nocturia. Significant correlations were found between the frequency of nocturnal urination and mean age, body mass index (BMI), respiratory disturbance index (RDI), apnea-hypopnea index (AHI), respiratory effort index (REI) and lowest oxygen saturation. The frequency of nocturnal urination showed significant differences between four groups of individuals with SDB (P<0.001). Nocturnal urination of more than three episodes per night was reported significantly more by severe SDB patients (P<0.001). Age, BMI, hypertension (HT), AHI, and REI were found to be significantly associated with nocturia.
    Sleep Medicine 06/2006; 7(4):362-7. · 3.49 Impact Factor
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    ABSTRACT: Sleep disturbances and daytime sleepiness are well-known phenomena in Parkinson's disease (PD). Fifteen previously untreated PD patients underwent clinical evaluation, subjective sleep evaluation and polysomnographic evaluation (PSG) before and after a treatment period of mean 8+/-3.1 months with dopaminergic drugs. Both mean Unified Parkinson's Disease Rating Scale (UPDRS) total score and mean subset III of the UPDRS were significantly improved with dopaminergic treatment. PSG revealed that administration of dopaminergic drugs resulted in significant increase in mean percentage of stages 1 and 2. The mean Epworth Sleepiness Scale (ESS) score was significantly increased and mean Multiple Sleep Latency Test (MSLT) score was significantly decreased after dopaminergic treatment indicating subjective and objective daytime sleepiness. The differences in MSLT scores were best explained by a higher dose of L-dopa, whereas other variables such as disease duration, treatment duration, Hoehn and Yahr stage, sleep efficiency index or dopamine agonists did not increase the significance. In contrast, any of the variables appeared to explain ESS score variability. This study demonstrates that daytime sleepiness is not present in untreated patients but emerges later during dopaminergic treatment. Total daily L-dopa dose is predictive of objective daytime sleepiness. Furthermore, subjective assessment of sleepiness may cause underestimation of the severity of daytime sleepiness.
    European Journal of Neurology 04/2005; 12(3):199-207. · 4.16 Impact Factor
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    Hakan Kaynak, Derya Kaynak, Ibrahim Oztura
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    ABSTRACT: Nocturia is an often-described symptom of sleep-disordered breathing (SDB). The aim of our study was to determine the frequency of nocturnal urination among patients with different severity of SDB and to find out whether frequency of nocturnal urination reflects the severity of disease. A retrospective chart review was conducted among 1075 subjects of suspected SDB. Nocturia was assessed using standard questionnaire evaluating a frequency of nocturnal urination. Subjects were divided into four groups of SDB based on the polysomnographic evaluation. In primary snoring group, 51% subjects did not complain nocturia, 28% subjects reported one time, 16% subjects reported two to three times and 5% subjects reported more than three times urination per night. Among patients with mild obstructive sleep apnea syndrome (OSAS), nocturnal urination was not reported by 36% and was reported one time by 34%, two to three times by 15%, more than 3 times by 15%. The corresponding frequencies among patients with moderate OSAS were 40, 31, 17 and 12%, and with severe OSAS were 23, 22, 23 and 32%, respectively. The severe OSA group was significantly different from other groups as regards the frequency of nocturnal urination (P < 0.001) while other OSA groups did not show any significance. Nocturnal urination of more than three times was significantly more reported by severe OSA patients ( P < 0.001) (positive predictive value = 0.71, negative predictive value = 0.62).
    Journal of Sleep Research 06/2004; 13(2):173-6. · 3.04 Impact Factor
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    ABSTRACT: To evaluate the effects of trazodone on subjective and objective measures of sleep in depressed insomnia patients treated with selective serotonin reuptake inhibitors (SSRIs). SSRIs can exacerbate or cause new insomnia while alleviating other symptoms of depression. Trazodone has been reported to be an effective hypnotic for patients with antidepressant-associated insomnia. Twelve female patients were given either 100 mg trazodone or placebo for 7 days in a double-blind crossover design with a 7-day washout period. Polysomnographic recordings were repeated on the 3rd, 9th and 17th, 23rd nights after treatment with trazodone or placebo. Sleep was assessed by Pittsburgh sleep quality index (PSQI) at the beginning and end of the study. Psychological evaluation was done by Hamilton depression rating scale (HDRS). Trazodone significantly increased total sleep time, percentage of stages 3+4, sleep efficiency index, sleep continuity index and decreased percentage of stage 1, number of awakenings, stage shifts compared to the baseline. This improvement was also obtained after 7 days of treatment. The PSQI score was reduced to 5+/-1.6 at the end of the study. HDRS was reduced to 11.5+/-4.5 with trazodone and to 12.2+/-3 with placebo. Trazodone is effective in the treatment of antidepressant-associated insomnia.
    Sleep Medicine 02/2004; 5(1):15-20. · 3.49 Impact Factor
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    ABSTRACT: Epidemiological studies have shown a strong association between sleep-disordered breathing (SDB) and cerebrovascular diseases. A total of 114 male patients, aged 40–65 years, referred to sleep laboratory for the evaluation of snoring and disturbed sleep were studied. Subjects were divided into three groups: habitual snoring, mild–moderate and severe obstructive sleep apnea syndrome (OSAS), respectively, determined by using three respiratory disturbance index (RDI) cut points (≤5, 5 < RDI < 30 and ≥30). Measurement of intima-media thickness (IMT) and the presence of plaque were determined by ultrasonographic evaluation. Major vascular risk factors such as hypertension, diabetes, smoking, hyperlipidemia, and obesity were determined. The OSA groups had significantly higher IMT values compared with the habitual snoring group. Three groups were significantly different with regard to the presence of plaque. Age and body mass index were found to be significantly associated with IMT while age and RDI were found to be most probably predictive for plaque. There were no significant differences amongst the three groups with respect to age, prevalence of hypertension and diabetes, smoking, total cholesterol and total triglyceride levels. These findings suggested that SDB is a predisposing factor for the atherosclerotic process and precipitate plaque particularly when associated with higher RDI.
    European Journal of Neurology 08/2003; 10(5):487 - 493. · 4.16 Impact Factor
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    ABSTRACT: Narcolepsy is a disabling sleep disorder characterized by excessive daytime sleepiness and abnormal manifestations of rapid eye movement (REM) sleep including cataplexy, sleep paralysis and hypnagogic hallucinations. It is known to be complex disorder in which both genetic predisposition and environmental factors play a role. In humans, susceptibility to narcolepsy is tightly associated with a specific HLA allele, DQB1*0602. In this report, we took advantage of the ongoing genetic study in Turkish narcoleptic patients to document clinical and genetic data of eight patients whose onset of symptoms were in the childhood period.
    The Turkish journal of pediatrics 44(4):321-5. · 0.56 Impact Factor
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    ABSTRACT: Background and Design.- Nasally applied continuous positive airway pressure (NCPAP) is a highly effective, nonsurgical form of treatment for obstructive sleep ap- nea. The NCPAP apparatus is bulky, cos- metically unappealing and associated with a number of adverse reactions. Several fac- tors such as severity of sleep apnea, exces- sive daytime sleepiness, previous surgery as well as NCPAP apparatus may have a role in acceptance and compliance of NCPAP therapy. Various desensitization techniques have been devised to help pa- tients better tolerate and accept treatment. In an attempt to identify effect of video as- sisted education on NCPAP acceptance, we evaluated 196 patients with obstructive sleep apnea referred to our laboratory for NCPAP trials. Patients were divided into two groups. Before undergoing first night NCPAP trial, the first group (n=84, male: 73%, female: 27%) was informed about their diagnosis, complications of the disease and mechanism of NCPAP treatment by an in- terview. The second group (n=112, male: 72%, female: 28%) was informed in the same manner and they watched video film