Anna Karlovasitou

Influence of sleep disturbance on quality of life of patients with epilepsy

The frequency of sleep disturbances in patients with epilepsy and their impact on quality of life (QoL) have been documented in a few reports, and the results are conflicting. We identified 124 consecutive epilepsy out-patients who visited the epilepsy out-patient clinics at the University Hospital of Alexandroupolis, the AHEPA Hospital in Thessaloniki and the Aeginitio Hospital in Athens. We measured excessive daytime sleepiness (EDS) with the Epworth Sleepiness Scale (ESS), obstructive sleep apnea (OSA) with the Sleep Apnea scale of the Sleep Disorders Questionnaire (SA-SDQ), and insomnia with the Athens Insomnia Scale (AIS). We evaluated quality of life by the Quality of Life in Epilepsy Inventory (QOLIE-31). EDS was found in 16.9% (21/124) of epileptic patients, OSA in 28.2% (35/124), and insomnia in 24.6% (30/122). In multivariate analysis, we found that insomnia was an independent negative factor for Total score (p<0.001), Overall QoL (p=0.002), Emotional well-being (p<0.001), Energy/fatigue (p<0.001), Cognitive functioning (p=0.04) and Social functioning (p=0.03), and OSA only for Cognitive functioning (p=0.01). According to our findings, EDS, OSA, and insomnia are frequent in epileptic patients. Epileptic patients with sleep disturbance, mainly insomnia, have significant QoL impairment.

Cholinergic deficiency in Alzheimer's and Parkinson's disease: Evaluation with pupillometry

The aim of the study was to evaluate the cholinergic deficiency in Alzheimers (AD) and Parkinsons disease (PD). For this purpose, pupil size changes and mobility were assessed using a fast-video pupillometer (263 frames/s). Twenty-three (23) patients with probable AD and twenty-two (22) patients with PD (eleven with cognitive impairment and eleven without) entered the study. A full record of the pupils reaction to light was registered. From this data ten (10) parameters were measured and reported. Comparison of those parameters in both group of subjects followed. Patients with probable AD had abnormal pupillary function compared to healthy ageing. All the Pupil Light Reflex (PLR) variables significantly differed between the two groups (p<0.005) except the Baseline Pupil Diameter after 2-min dark adaptation (D1) and the Minimum Pupil Diameter (D2). Maximum Constriction Acceleration (ACmax) was the best predictor in classifying a subject as normal or as an AD with a perfect classification ability (AUC=1, p<0.001). ACmax and Maximum Constriction Velocity (VCmax) were significantly lower in PD patients without and with coexisting cognitive impairment compared to normal subjects (p<0.001). Patients with cognitive impairment had significantly lower levels of ACmax, VCmax and amplitude (AMP=D1-D2) than patients with no cognitive deficits. ACmax and secondarily VCmax were the best predictors in classifying a subject as normal or as a PD patient with or without cognitive impairment. Cognitive and memory impairment, which reflects a cholinergic deficit, may be a crucial pathogenetic factor for the decrease in the aforementioned pupillometric parameters. VCmax and ACmax can be considered as the most sensitive indicators of this cholinergic deficiency.

Pupil Light Reflex in Parkinson's Disease: Evaluation With Pupillometry

ABSTRACT We evaluated pupil light reflex (PLR) in patients with Parkinsons disease (PD) and normal controls by means of pupillometry and explored its possible relation to clinical characteristics in parkinsonian patients. PLR was evaluated using pupillometry in 66 patients with PD without clinical evidence of autonomic dysfunction and 44 healthy matched controls. PLR was elicited by single flash stimuli of 24.6 candelas/m2 intensity and 20 ms duration, and six parameters were studied after full recording of pupils movement. A significant increase in latency (T1) and significant decrease in amplitude (R1–R2), maximum constriction velocity (Vmax), as well as maximum acceleration (ACmax) was found in parkinsonian patients. There was no significant difference in initial radius (R1) and minimum radius (R2) values. Of the parameters studied, ACmax emerged as a significant predictor for discrimination between PD patients and controls. There was no significant correlation between pupillometry parameters and clinical characteristic of patients (disease duration, stage, and the Unified Parkinsons Disease Rating motor scale). The study demonstrates PLR disorder in PD patients even without overt clinical autonomic dysfunction. Pupillometry appears to be a useful and noninvasive method for exploration of PLR alterations in PD and may prove to be useful for the early detection of subclinical autonomic nervous system dysfunction.

Improved detection of amnestic MCI by means of discriminative vector quantization of single-trial cognitive ERP responses

Cognitive event-related potentials (ERPs) are widely employed in the study of dementive disorders. The morphology of averaged response is known to be under the influence of neurodegenerative processes and exploited for diagnostic purposes. This work is built over the idea that there is additional information in the dynamics of single-trial responses. We introduce a novel way to detect mild cognitive impairment (MCI) from the recordings of auditory ERP responses. Using single trial responses from a cohort of 25 amnestic MCI patients and a group of age-matched controls, we suggest a descriptor capable of encapsulating single-trial (ST) response dynamics for the benefit of early diagnosis. A customized vector quantization (VQ) scheme is first employed to summarize the overall set of ST-responses by means of a small-sized codebook of brain waves that is semantically organized. Each ST-response is then treated as a trajectory that can be encoded as a sequence of code vectors. A subjects set of responses is consequently represented as a histogram of activated code vectors. Discriminating MCI patients from healthy controls is based on the deduced response profiles and carried out by means of a standard machine learning procedure. The novel response representation was found to improve significantly MCI detection with respect to the standard alternative representation obtained via ensemble averaging (13% in terms of sensitivity and 6% in terms of specificity). Hence, the role of cognitive ERPs as biomarker for MCI can be enhanced by adopting the delicate description of our VQ scheme.

Pupillometry and 123I-DaTSCAN imaging in Parkinson's Disease: A Comparison Study

ABSTRACT The purpose of this study was the evaluation of pupil light reflex (PLR) in patients with Parkinsons disease (PD) by using a modern pupillometry system and the investigation of its potential relationship with dopamine transporter imaging (DaTSCAN), which is an objective method for the evaluation of presynaptic dopaminergic system. PLR was evaluated using pupillometry in 35 patients with PD without clinical evidence of autonomic dysfunction and 44 healthy matched controls. PLR was elicited using a fully automated pupillometry system and six parameters were measured. Dopamine transporter imaging was performed using radioactive ioflupane 123I-FP-CIT [123I-N-ω-fluoropropyl-2β-carbomethoxy-3β-(4-iodophenyl)-nortropane]. A significant increase in latency and a significant decrease in amplitude, maximum constriction velocity, as well as maximum acceleration were observed in PD patients. There was no significant difference in initial radius and minimum radius values. Investigating the relationship between pupillometry parameters and 123I-FP-CIT binding values, we correlated values from the semiquantitative analysis of radioligand uptake with pupillometry parameters, but we found no significant correlation. This study demonstrates PLR impairment in patients with PD without overt autonomic dysfunction. This impairment does not seem to correspond to the reduction of radioligand binding in the striatum as the result of presynaptic dopaminergic dysfunction, suggesting a different deterioration rate of these systems.

Transient hypnic headache syndrome in a patient with bipolar disorder after the withdrawal of long-term lithium treatment : a case report

The hypnic headache syndrome (HHS) or ‘alarm clock’ headache was first described by Raskin in 1988 (1). Less than 100 cases have been reported in the international literature, while the estimated incidence of the syndrome is 0.07%. The female/ male ratio is now considered to be 1.7/1 (2–4). HHS was included in the classification of the International Headache Society (IHS) in 2004, coded under the category ‘4.Other Primary Headaches’ (2, 5). The HHS is a benign syndrome characterized by recurrent episodes of headache occurring always during sleep. The episodes characteristically result in the awakening of the patient and they are not accompanied by any autonomic symptoms. The onset of the syndrome occurs usually after the age of 50 years, while lithium is the most effective treatment in the case of HHS (2, 3, 6). The pathogenetic mechanism of HHS remains unidentified. No other case of HHS occurring after the withdrawal of long-term lithium treatment has been reported in the literature to date.

Differential effects of lacosamide, phenytoin and topiramate on peripheral nerve excitability: An ex vivo electrophysiological study

BACKGROUND Antiepileptic drugs (AEDs) are mainly used to control cortical hyperexcitability. Some of them (e.g. phenytoin (PHT) and topiramate (TPM)) have also effects on the peripheral nervous system (PNS). Lacosamide (LCM) is a novel AED that stabilizes hyperexcitable neuronal membranes by selectively enhancing the slow inactivation of voltage-gated sodium channels (VGSCs). Although the mechanism of action of LCM is fairly well understood, there are no in vitro data available regarding any possible PNS effects of LCM. OBJECTIVE To investigate, in vitro, the effects of LCM on peripheral nerve excitability in comparison with PHT and TPM, two AEDs that act, in part, by stabilizing the fast inactivation state of VGSCs. METHODS Experiments were conducted on the isolated sciatic nerve of the adult rat using standard electrophysiological methods. The effects of LCM on the amplitude and latency of the evoked compound action potential (CAP) during a 48h period of drug exposure were recorded and compared with the effects of PHT and TPM. RESULTS LCM produced inhibitory effects on CAP at concentrations significantly higher than the therapeutic levels (>25μg/ml). At these concentrations (62.57-125.15μg/ml), an acute and immediate increment of the latency and decrement of the amplitude of the CAP were observed. In contrast to LCM, PHT caused an acute decrement in the amplitude as well as an increment in the latency of the CAP even at subtherapeutic levels (5μg/ml). With regard to TPM, the amplitude of the CAP was not affected at the supratherapeutic concentrations but at the therapeutic concentration of 33.94μg/ml a reduced decrement of the CAP amplitude compared to the controls was observed. CONCLUSIONS LCM, PHT and TPM exert differential effects on peripheral nerve excitability. PHT inhibited the sciatic nerve CAP even at subtherapeutic levels whereas LCM was safe within the therapeutic concentration range. TPM did not affect the CAP amplitude even at high supratherapeutic concentrations whereas in the therapeutic range a neuroprotective effect was observed. Possible underlying mechanisms and the clinical implications of these findings are discussed.

The impact of audio-visual stimulation on alpha brain oscillations: An EEG study

Many studies investigated the brain responses as a reaction in auditory or visual stimuli separately. However a few studies have been published so far investigating the interactions of the two aforementioned stimuli. The current study comes to examine the impact of the audio-visual stimulation with binaural beats and flickering light in four different colors on low and upper alpha oscillations. For this purpose electroencephalogram (EEG) was adopted and Event Related Desynchronization/Event Related Synchronization (ERD/ERS) has been used as an index in order to investigate the alpha brain responses. Statistically significant results suggest that the combination of audio-visual stimuli with binaural beats and flickering light color at 8 and 10 Hz respectively can evoke significant Following Frequency Response (FFR) of the low and upper alpha oscillations.

CLINICAL CASE: VERMIS HYPOPLASIA WITH FEATURES OF SMITH-LEMLI-OPITZ SYNDROME

This article attempts to describe a very unusual case of a boy aged 15, who has had intractable epileptic phenomena, mental retardation, megalocephaly, micrognathy, syndactyly, small tongue, hypoplastic genitalia, gynecomasty, obesity, and slight left body hemiatrophy. Neurologically the patient has had hypotonia of the lower limbs, cerebellar dysfunction including horizontal nystagmus, bilateral intention tremor, dysdiadokokinesia, gait ataxia. The clinical investigation revealed low plasma cholesterol and hypoplasia of the vermis in MRI. The epileptic phenomena were intractable and polymorphous. One should have thought that this is an unusual case of Smith-Lemli-Opitz syndrome associated with features of Joubert syndrome.

Using EEG Frontal Asymmetry to Predict IT User’s Perceptions Regarding Usefulness, Ease of Use and Playfulness

Information systems (IS) community is increasingly interested in employing neuroscience tools and methods in order to develop new theories concerning Human–computer interaction (HCI) and further understand IS acceptance models. The new field of NeuroIS has been introduced to address these issues. NeuroIS researchers have proposed encephalography (EEG), among other neuroscience instruments, as a valuable usability metric, when used effectively in appropriately designed experiments. Moreover, numerous researchers have suggested that EEG frontal asymmetry may serve as an important metric of user experience. Based on the aforementioned evidence, this study aims to integrate frontal asymmetry with Technology acceptance model (TAM). Particularly, we assumed that frontal asymmetry might predict users’ perceptions regarding Usefulness and Ease of Use. Furthermore, we hypothesized that frontal asymmetry might also affect (influence) users’ Perceived Playfulness. Specifically, 82 (43 females and 39 males) undergraduate students were chosen to use a Computer-Based Assessment (while being connected to the EEG) in the context of an introductory informatics course. Results confirmed our hypothesis as well as points of theory about Information technology (IT) acceptance variables. This is one of the first studies to suggest that frontal asymmetry could serve as a valuable tool for examining IT acceptance constructs and better understanding HCI.