Exploration of cortical inhibition and habituation in insomnia: Based on CNV and EEG

Cognitive dysfunction with abnormal cortical inhibition and habituation has frequently been found in patients with insomnia. And the so-called contingent negative variation (CNV) and EEG power spectral density (FFT) may be the best choice to explore the underlining pathophysiology.

We used polysomnography (PSG) to record such objective PSG parameters. The amplitudes, latencies, areas of different CNV components such as oCNV, iCNV and tCNV, PINV have been selected and analyzed. Behavioral data such as manual reaction time (RT) has been analyzed. Spectral analysis was performed with fast Fourier transformation (FFT) on all channels to make a spectral analyses of EEG datas.

The A-latency located in CZ or PZ were statistically longer in insomnia group than control group, the iCNV-latency located in insomnia group were statistically shorter than control group. The iCNV-amplitude located in insomnia group was lower than control group. The oCNV-amplitude or the tCNV-amplitude located in insomnia group was higher than control group. The oCNV-square, tCNV-square, or PINV-square located in insomnia group were significant larger than control group. β1 or β2 activity distributed in bilateral hemisphere were significantly increased in insomnia group than control group with different distributions.

Our study revealed varied attentional and information processing in insomnia patients. Above all, we made a hypothesis with ceiling theory: Frontal lobe play an important role in maintaining cognitive processing, which needs much more energy consumption and leads to decreased fast EEG activity in frontal cortex, which contributes to reduced cortical inhibition, represented as abnormal CNV.