Syncope is defined as transient loss of consciousness as a result of cerebral hypoperfusion. Electroencephalography during syncope shows either a 'slow-flat-slow' or a 'slow' pattern. The first is believed to denote more severe hypoperfusion. Although the diagnosis of vasovagal syncope relies primarily on history taking, there is limited evidence regarding the relative importance of various clinical features, and none that relate them to the severity of electroencephalographic changes. The aim of this investigation was to study symptoms, signs and electroencephalographic changes with a 1 s resolution using electroencephalography and video data in 69 cases of tilt-induced vasovagal syncope. The main finding was that flattening of the electroencephalograph indicated more profound circulatory changes: the 'slow-flat-slow' group had a lower minimum blood pressure, longer maximum RR-interval, contained more cases with asystole and had a longer duration of loss of consciousness than the 'slow' group. Second, we describe a range of signs, including some that have rarely been reported in syncope, e.g. oral automatisms. Third, signs occurred at different rates depending on electroencephalographic flattening, suggesting a classification of syncopal signs. Type A signs (e.g. loss of consciousness, eye opening and general stiffening) develop during the first slow phase, stay present during flattening and stop in the second slow phase. Type B (particularly myoclonic jerks) occur when the electroencephalograph is slow but not flat: their abolition with electroencephalographic flattening suggests dependence on cortical activity. Type C signs (making sounds, roving eye movements and stertorous breathing) occur only in the flat phase, whereas type D (dropping the jaw and snoring) may occur either in slow or flat phases. In conclusion, our findings provide a detailed assessment of clinical symptoms in relation to electroencephalographic (EEG) changes during tilt-induced syncope.
Objectives: To provide a detailed semiology to aid the clinical recognition of psychogenic pseudosyncope (PPS), which concerns episodes of apparent transient loss of consciousness (TLOC) that mimic syncope. Methods:We analyzed all consecutive tilt-table tests from 2006 to 2012 showing proven PPS, i.e., apparent TLOC had occurred without EEG changes or a decrease in heart rate (HR) or blood pressure (BP). We analyzed baseline characteristics, video data, EEG, ECG, and continuous BP measurements on a 1-second time scale. Data were compared with those of 69 cases of tilt-induced vasovagal syncope (VVS).Results: Of 800 tilt-table tests, 43 (5.4%) resulted in PPS. The majority (74%) were women. The median duration of apparent TLOC was longer in PPS (44 seconds) than in VVS (20 seconds, p , 0.05). During the event, the eyes were closed in 97% in PPS but in only 7% in VVS (p , 0.0001). A sudden head drop or moving down the tilt table was more common in PPS than in VVS (p , 0.01), but jerking movements occurred more frequently in VVS (p , 0.0001). In PPS, both HR and BP increased before and during apparent TLOC (p , 0.0001).Conclusions: PPS is clinically distinct from VVS and can be diagnosed accurately with tilt-table testing and simultaneous EEG monitoring. Compared with VVS, eye closure during the event, long periods of apparent TLOC, and high HR and BP are highly specific for PPS. Improved understanding of the semiology of PPS as a clinical entity is vital to ensure accurate diagnosis. Neurology â 2013;81:752-758 GLOSSARY BP 5 blood pressure; DBP 5 diastolic blood pressure; HR 5 heart rate; PNES 5 psychogenic nonepileptic seizure; PPS 5 psychogenic pseudosyncope; SBP 5 systolic blood pressure; sMAP 5 smoothed mean arterial pressure; TLOC 5 transient loss of consciousness; VVS 5 vasovagal syncope.Transient loss of consciousness (TLOC) is the reason for approximately 3% of all emergency department visits. 1 The most common major causes of apparent TLOC are syncope, epileptic seizures, and psychogenic events. [2][3][4] The pathophysiology of psychogenic and somatic apparent TLOC is different, but they can be difficult to distinguish clinically.Psychogenic apparent TLOC bears various labels. When episodes involve pronounced movements, they resemble epilepsy and are frequently labeled psychogenic nonepileptic seizures (PNES). 5 Episodes without pronounced movements resemble syncope and are generally labeled psychogenic pseudosyncope (PPS). 3 PNES and PPS are probably manifestations of the same underlying psychiatric disorder, but their different presentation has important consequences for diagnosis. PNES is relatively well known, with a reported prevalence of up to 30% in patients in epilepsy clinics. 5 In contrast, PPS is rarely mentioned in the literature on syncope, and the reported prevalence of PPS in those analyzed for presumed syncope is lower, ranging from 0% to 8%. [6][7][8]
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