Comparison of time perception in individuals between focal and generalized epilepsy.

Clinical Neurophysiology: EEG–Video Monitoring

To evaluate the effects of adjunctive pregabalin 300 mg/day versus placebo on polysomnographic (PSG) variables in patients with well controlled partial seizures and subjectively reported sleep disturbance. An exploratory, 4-week, double-blind, randomized study in patients with well controlled partial seizures on AED monotherapy and subjective sleep disturbance over the previous 6 months. Mean changes from baseline to endpoint in PSG and subjective sleep variables (MOS Sleep Scale, Groningen Sleep Questionnaire) in patients on adjunctive pregabalin 300 mg/day (n=8) were compared with patients on placebo (n=7). Baseline PSGs showed sleep fragmentation. Mean sleep efficiency improved significantly in both treatment groups in the mean baseline to endpoint change; there was no significant between-group difference. Pregabalin treatment was associated with a significant reduction in number of awakenings (p = 0.02), and improvement in wake time after sleep onset approached significance (p = 0.055), suggesting improvement in sleep continuity that was not observed in the placebo group. Pregabalin was also associated with significant improvements in the MOS sleep disturbance and sleep quantity subscales compared with placebo (p < or =0.03). There were no changes in self-reported seizure control. This exploratory pilot study suggests that pregabalin may improve sleep continuity in patients with clinically relevant sleep disturbance. The effect on disturbed sleep appears independent of seizure control. The effects of pregabalin on disturbed sleep and seizures and their interrelationships warrant further study.

Nicotine withdrawal leads to impulsive decision-making, which reflects a preference for smaller, immediate rewards and often prompts a relapse to smoking. The mechanism by which nicotine withdrawal leads to impulsive decision-making is not well known. An essential dimension of decision-making is time perception. Impulsive decisions reflect intolerance of temporal delays and the perception that time is passing more slowly. Sex may be an important factor in impulsive decision-making and time perception, but no studies have investigated whether sex moderates the effects of nicotine withdrawal on impulsive decision-making and time perception. Thirty-three (12 female) adult smokers completed 2 laboratory sessions: following 24-hr abstinence and once smoking-as-usual (order counterbalanced, abstinence biochemically verified). Participants completed 2 time perception tasks, a decision-making task, and self-report measures of craving, withdrawal, and mood. During time reproduction, males overestimated time during abstinence compared to smoking, whereas there was no session effect for females. On the time discrimination task, smokers were less accurate during abstinence, and this effect tended to be stronger among females. In general, males had higher discounting rates compared with females, but there was no effect of abstinence. The current data suggest that the effect of abstinence on time perception may be stronger in males and that males generally exhibit steeper delay discounting rates. Time perception may be an important mechanism in smoking abstinence. Our future work will investigate the role of time perception in smoking relapse and whether this is moderated by sex.

Impaired decision-making and time perception in individuals with stroke: Behavioral and neural correlates

This study investigates the role of individual differences in time perception on task performance during teleoperation with latency. Long distance teleoperation induces latency, causing performance issues for the operator. Previous research demonstrated that individual differences in time perception predicted performance on a similar task, having participants navigate a radio controlled (RC) car around a track. This work extends the relationship into routes of varying course width to test whether differences in time perception predict movement over-/underestimation. Participants completed a time estimation task and a route navigation task while experiencing latency. In the time estimation task, participants estimated the duration of multiple visual stimuli (2 s or less). In the route navigation task, participants moved a virtual cube across a route. Each trial varied in the amount of latency and the amount of horizontal clearance in the track (4-10 m for a 1.2-m-long/wide cube). The results showed fairly consistent latency by time estimation and latency by clearance interaction effects on a wide set of trial-level variables, such as completion time, and action-level performance variables, such as time spent moving per move event. However, the results were not consistently in the predicted direction. Results suggest that clearance and timing affect performance across latency, at both the overall level (i.e., trial completion time) and at the action level (time spent moving). An open question remains as to how these contextual factors affect movement strategy selection.

Time flies when you maximize — Maximizers and satisficers perceive time differently when making decisions

Elevated serum neuron-specific enolase in patients with temporal lobe epilepsy: A video–EEG study

Fifty-four idiopathic status convulsivus (SC) cases were followed prospectively for a period between 5 and 21 years, the average being 13 years. Three-fourths of the cases had no residuals. There were two patterns of subsequent epilepsy; 1) complex partial seizures (CPS) with or without secondarily generalization (GTS) developed 4.3 +/- 3.5 years after febrile SC, 2) unilateral seizures or CPS +/- GTS developed 1.2 +/- 1.0 years after afebrile SC. The seizure prognosis of these cases was good except for some cases in the former group. There have been two kinds of theories regarding SC and epilepsy until now. One was derived from retrospective studies: SC and/or complex febrile convulsion (FC) were considered the main causes of temporal lobe epilepsy (TLE) producing mesial temporal sclerosis (MTS). Another was derived from prospective studies, in which the relation between FC and TLE was considered weak. Our results revealed that 6 cases (15%) out of 30 febrile SC developed epilepsy, and that five of those six cases were diagnosed as CPS. Three of 5 CPS cases were diagnosed as TLE. Recently the seizure prognosis of operative therapy for TLE--especially the MTS type--has been very favorable. Furthermore, it has become easy to find MTS by Magnetic Resonance Imaging (MRI). So, we emphasize that a precise follow-up study of SC using MRI, EEG, etc., is important in deciding the appropriate therapy for TLE, as well as in the study of the pathogenesis of TLE.

Bipolar disorder (BD) and temporal lobe epilepsy (TLE) overlap in domains including epidemiology, treatment response, shared neurotransmitter involvement and temporal lobe pathology. Comparison of cognitive function in both disorders may indicate temporal lobe mediated processes relevant to BD. This systematic review examines neuropsychological test profiles in euthymic bipolar disorder type I (BD-I) and pre-surgical TLE and compares experimental designs used. A search of PubMed, PsychINFO, and Scopus using Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines was conducted. Inclusion criteria were comparison group or pre- to post-surgical patients; reported neuropsychological tests; participants aged 18-60 years. Fifty six studies met criteria: 27 BD-I; 29 TLE. Deficits in BD-I compared to healthy controls (HC) were in executive function, attention span and verbal memory. Deficits in TLE compared to HC were in executive function and memory. In the pre- to post-surgical comparisons, verbal memory in left temporal lobe (LTL) and, less consistently, visuospatial memory in right temporal lobe (RTL) epilepsy declined following surgery. BD-I studies used comprehensive test batteries in well-defined euthymic patients compared to matched HC groups. TLE studies used convenience samples pre- to post-surgery, comparing LTL and RTL subgroups, few included comparisons to HC (5 studies). TLE studies typically examined a narrow range of known temporal lobe-mediated neuropsychological functions, particularly verbal and visuospatial memory. Both disorders exhibit deficits in executive function and verbal memory suggestive of both frontal and temporal lobe involvement. However, deficits in TLE are measured pre- to post-surgery and not controlled at baseline pre-surgery. Further research involving a head-to-head comparison of the two disorders on a broad range of neuropsychological tests is needed to clarify the nature and extent of cognitive deficits and potential overlaps.

32 extraverted and 32 introverted college students rated the interest value and estimated the duration of 3-min. intervals filled with reading. There were 3 dull and 3 interesting readings. It was hypothesized that time perceptions of extraverts and introverts would differ when their interest in the task was dissimilar. But no personality differences in time perception and few in interest were found; both extraverts and introverts judged the intervals to be shorter when the reading was interesting.

The display duration of stimuli is overestimated due to the increase in phasic arousal induced by the stimuli or high levels of background arousal. A previous study demonstrated that display duration of items (2 s) was overestimated when a participant attempted to conceal one of the items so as not to be detected in the concealed information test (CIT). As the time perception remained the same between the item to be concealed and the other items, the overestimation was thought to be due to the high level of background arousal under the conceal condition. Duration of 2 s may be too long to examine the phasic arousal effect induced by the concealed item. The present study conducted three online experiments with shorter durations, that is, each of three items was presented with duration of 1, 0.5, and 2 s in Experiments 1, 2, and 3, respectively. The participants were instructed to conceal one of the three items under the conceal condition and did not conceal any item in the innocent condition. The difference in time perception between the conceal and innocent conditions or between items under the conceal condition was observed in none of the three experiments. The result indicates that temporal overestimation does not occur when a participant is only concealing an object. Rather, temporal overestimation would occur only when the level of background arousal is amplified by the concealment.

Delay-discounting studies in neuroscience, psychology, and economics have been mostly focused on concepts of self-control, reward evaluation, and discounting. Another important relationship to consider is the link between intertemporal choice and time perception. We presented 50 college students with timing tasks on the range of seconds to minutes and intertemporal-choice tasks on both the time-scale of seconds and of days. We hypothesized that individual differences in time perception would influence decisions about short experienced delays but not long delays. While we found some evidence that individual differences in internal clock speed account for some unexplained variance between choices across time-horizons, overall our findings suggest a nominal contribution of the altered sense of time in intertemporal choice.

Time perception reflects individual differences in motor and non-motor symptoms of Parkinson's disease

Do recurrent seizures cause neuronal damage? A series of studies with MRI volumetry in adults with partial epilepsy

Epilepsy is a major neurological disorder that affects 0.5-2.0% of the global population (Hauser, 1998; Picot et al.; 2008). The term “epilepsy” likely encompasses a number of various etiological and pathophysiological processes. The International League Against Epilepsy (ILAE) has classified the epilepsies as being either focal or generalized. In all likelihood, this classification implies different causes and anatomical/functional substrates. Epileptogenesis (the processes by which epilepsy develops within an otherwise normal brain) probably differs for the various types of epilepsy (Luders, 2008). In this sense, epileptogenesis of (for example) temporal lobe epilepsy (TLE) with hippocampal sclerosis (HS), would be different from that observed in patients with cortical dysplasia; this would hold true for other cryptogenic or idiopathic focal epilepsies as well. Therefore, to date, it has not been possible to establish a unique underlying cause or mechanism that is involved in the transition from normal to epileptic cortical tissue, although there are several hypotheses to explain the different types of seizures and epilepsies. From a therapeutic point of view, the epilepsies in humans can be divided into pharmaco sensitive and pharmaco resistant. In the former, the patient is successfully treated by one or more anti-epileptic drugs (AED). Nearly two-thirds of patients respond to anticonvulsant therapy. However, in a significant percentage of patients, the seizures cannot be controlled by drugs, despite verifying both maximal dosage and an adequate treatment duration. The percentages of medical intractability among epileptic patients are: focal epilepsy, 24%; idiopathic epilepsy, 9.3%; and catastrophic epilepsy, 66.7% (Lardizabal, 2008). In some cases, a viable therapeutic option is surgery. Generally, the candidates for this treatment are patients who suffer from focal or partial epilepsy. In these patients, it is possible—at least in theory—to identify a well-defined area of the cortex that is responsible for the seizures; this is known as the epileptic zone (EZ). From an operational point of view, the EZ is defined as the region in which excision or disconnection relieves the patient from seizures. This option frequently involves removing the brain section where the EZ is located, and this possibility offers a unique opportunity to gain access to the real processes (the neural networks, membrane properties and synaptic dynamics) underlying partial epilepsy in human patients. TLE is the most common form of partial epilepsy in adults and is usually drug-resistant (Engel 2001; Wieser, 2004). This type of pathology is frequently associated with a salient pathological condition called hippocampal sclerosis (see Figure 1 -Kuzniecky et al.; 1987).