Table 1.
Summary of studies of auditory ERPs in MCI and AD patients.
| Waveform | Description | Changes in MCI | Changes in AD | References |
|---|---|---|---|---|
| ABR | Series of peaks recorded within the first 10 milliseconds following an auditory stimulus. Correlated with transmission of auditory sensory information from the auditory nerve to the inferior colliculus. | None | None | AD: Grimes et al. (1987), Rowe (1981) |
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| MMN | ERP recorded in response to infrequent deviant sound. Measurement of automatic detection of changes in stimulus related to pre-attentive sensory memory. | None | None | AD: Kazmerski et al. (1997), Pekkonen (2000) |
| P50 | Positive peak between 40 and 75 milliseconds representing function of the reticular activating system and thalamus in ‘sensory gating.’ Increases in amplitude associated with | Increased amplitude | Increased amplitude | MCI: Golob et al. (2007), Golob et al. (2002), Irimajiri et al. (2005). AD: Cancelli et al. (2006), Golob and Starr (2000) |
| N200 | Negative peak between 180–350 milliseconds elicited in response to presentation of an infrequent stimulus during an oddball paradigm or novel stimuli. | Increased latency | Increased latency | MCI: Bennys et al. (2007), Bennys et al. (2011), Cintra et al. (2017), Papaliagkas et al. (2008), Papaliagkas et al. (2009), Papaliagkas et al. (2011), AD: Bennys et al. (2007), Caravaglios et al. (2008), Cintra et al. (2017) |
| P300 | Positive peak between 250–400 milliseconds elicited in response to an unexpected stimulus. Produced by activity of multiple structures in the medial temporal lobe. Larger amplitudes reffective of greater attention and shorter latency associated with superior mental performance. | Increased latency | Increased latency (except Golob and Starr which showed decreased latency) Decreased amplitude* | MCI: Golob et al. (2002) and Golob et al. (2007) AD: Goodin et al. (1978), Polich et al. (1990), Golob and Starr (2000), Frodl et al. (2002), Polich and Corey-Bloom (2005) |
| N400 | Negative wave between 300–550 milliseconds arising from multiple generators found in both medial and lateral temporal regions. Related to semantic processing demands and demonstrates reduction in amplitude with presentation of semantically congruous words. | Lack of decrease in amplitude to semantically congruous stimulus | Lack of decrease in amplitude to semantically congruous stimulus | MCI: Olichney et al. (2002), Olichney et al. (2008), and Olichney et al. (2013). AD: Ford et al. (1996), Iragui et al. (1996), Olichney et al. (2006) |
| P600 | Positive wave between 550–800 milliseconds arising from multiple generators in the medial temporal lobe and paralimbic cortical regions. Implicated as an index of memory encoding that demonstrates reduction in amplitude to semantically primed or repeated words. | Lack of decrease in amplitude to semantically congruous stimulus | Lack of decrease in amplitude to semantically congruous stimulus | MCI: Olichney et al. (2002), Olichney et al. (2008), and Olichney et al. (2013). AD: Olichney et al. (2006) |
| FFR/N1-P2 | Dual protocol measuring neuroelectric activity in the auditory brainstem (FFR) and cortical ERP’s simultaneously. | Increased FFR response and N1-P2 amplitudes | N/a | MCI: Bidelman et al. (2017) |