To explore the changes of cognitive function and potential in patients with medication-overuse headache (MOH).

The subjects were divided into two groups: observation group (patients with MOH, n=30) and control group (n=30). P300 was used to detect the cognitive potential and mini mental state examination (MMSE) was performed to evaluate the cognitive function of the subjects.

The differences between the two groups were significant.The P3 latency in observation group [(393.70±42.60) ms] was more prolonged than that in the control group (331.05±22.35) ms]. The difference between the two groups was significant(t=7.13, P<0.05); The amplitudes of P3 in observation group [(3.40±2.30)uV], was lower than that in the control group[ (6.20±2.40)uV]. The difference between the two groups was also significant(t=4.59, P<0.05). The MMSE in observation group were shown as follows: total score (24.00±2.21), orientation (8.15±0.86), anamnesis (2.88±0.23), calculation (3.07±1.04), recall (1.72±0.89) and language (8.42±1.33). In control group, the MMSE were shown as total score (27.07±2.06), orientation (9.28±1.03), anamnesis (3.01±0.26), calculation (3.25±1.20), recall (1.92±0.90) and language (9.69±1.44). The differences between the two groups were all significant (t=3.66, 3.19, 3.34, P<0.01).

The patients with MOH had the mild cognitive impairment, and P300 cognitive potential could provide objective indicators for the diagnosis of cognitive dysfunction of patients with MOH.