Multimodal event‐related potential P3 after transient global amnesia

Abstract

The putative generators of the event-related P3 component are still a matter of debate. There is reasonable evidence that the mesial temporal lobe structures are crucial in the generation of event-related potentials. Transient global amnesia (TGA) is characterized by anterograde and retrograde amnesia without neurological deficits in which a temporal hypoperfusion is the most likely pathomechanism. The aim of this study is to evaluate a possible delay in the P3 latency in a cohort of patients with TGA (n = 18). We used classic oddball paradigms with visual and auditory stimuli. The P3 latencies were compared to 18 age-matched patients with transient ischaemic attacks (TIAs) in the carotid artery territory and 23 age-matched controls. The mean age of the patients was 60.1 years (SD 14.1), in the TIA group 64.7 (SD 12.1) and 57.7 (SD 10.1) in the controls; the mean time interval between onset of TGA symptoms and performance of P3 investigations was 4.3 days (range 1-7 days); and the mean latencies measured at the vertex (Cz electrode) were 422.9 ms (SD 44.6) for the TGA patients, 436.4 ms (SD 62.1) for the TIA group, and 409.3 ms (SD 48.5) for the controls in the visual paradigm and 371.7 ms (SD 41.7), 399.7 ms (SD 51.2) and 385.3 ms (SD 46.5) in the auditory paradigm for the TGA, the TIA and the control groups. The P-values were not significant. These results suggest different neuronal networks in the generation of scalp P3 from those responsible for the disturbance of episodic memory in TGA.

Event related potentials in patients with transient global amnesia—A prospective controlled study

“…In summary, the results of that investigation showed no significant difference in the mean latencies of P3 in TGA patients compared to patients suffering from TIA as well as healthy controls [19]. Nevertheless, a measureable increase of the latency in the visual P3 of TGA patients compared to a control group was found in that investigation without reaching statistical significance.…”

“…The mesial temporal lobe structures are discussed as being both the dysfunctional region responsible for TGA and the generator of the P3 wave in ERP [19,30]. Our findings contribute to the identification of this brain region to be involved in TGA.…”

“…To our knowledge, there is only one other study investigating ERP in more than three patients (namely 18 patients) with TGA [19]. In summary, the results of that investigation showed no significant difference in the mean latencies of P3 in TGA patients compared to patients suffering from TIA as well as healthy controls [19].…”

“…Event-related potentials (ERP) are regarded as an objective tool to measure individual cognitive memory functions [18] and have been investigated in TGA [19]. They represent the cognitive processing of relevant stimuli as a correlate of brain electric activity.…”

Multimodal P3 under different attentional states in mesial temporal lobe epilepsy

“…Although the generators of the P3 in humans are not known, studies from depth electrodes in epileptic patients suggest local generation of the P3 by mesial temporal lobe structures (limbic P3) (Halgren et al ., 1986; McCarthy and Wood, 1987; Smith et al ., 1990; Grunwald et al ., 1995, 1998, 1999) and the temporoparietal junction (Knight et al ., 1989). However, the contribution of subcortical (Onofrj et al ., 1992a; Trinka et al ., 2000a) and mesial temporal structures to scalp P3 is uncertain (Johnson 1986; Johnson and Fedio, 1988; Daruna et al ., 1989; Rugg et al ., 1991; Puce and Bladin, 1991; Onofrj et al ., 1991, 1992b; Polich and Squire, 1993; Nishitani et al ., 1999; Trinka et al ., 2000b). Nelson and coworkers demonstrated alterations of the scalp recorded P3 using a complex visual language discrimination task in patients with mesial temporal lobe epilepsy (mTLE), but lateralization of the seizure focus was not obtained in this study (Nelson et al ., 1991).…”