A 1-month ketogenic diet in patients with migraine gives a clinical beneficial effect associated with increased latency of somatosensory thalamo-cortical activity

Objective: Since the habituation deficit of evoked potentials could be related to abnormal thalamocortical drive, we searched for a modulatory effect of ketogenic diet (KD) on somatosensory-evoked thalamo-cortical activity. KD is effective in preventing migraine. Previous studies showed that KD normalises habituation of somatosensory and visual cortical evoked responses in parallel with a decrease in of migraine attack frequency. Methods: We electrically stimulated the median nerve at the wrist to record somatosensory high-frequency oscillations (HFOs) in twenty patients with episodic migraine with and without aura before and after one month of normo- (n = 9) or hypocaloric KD (n = 11). For pre-synaptic thalamocortical and post-synaptic cortical HFOs, we measured the latency of the negative oscillatory maximum, the intra-burst frequency, the number of negative peaks, and the maximum peak-to-peak amplitude. Results: In the total group of patients, the one-month KD significantly increased the latency of the negative oscillatory maximum in pre-synaptic, i.e. thalamocortical activity (t = 2.70, p = 0.015) and in post-synaptic HFOs, i.e. cortical activity (t = 3.08, p = 0.006). This effect could be attributed to hypo-caloric KD, as it was not found after normo-caloric KD. Other HFO parameters, such as amplitude, duration, or number of oscillations, were not affected. Conclusions: A 1-month hypo-caloric KD is able to delay the propagation of neuronal activity through the thalamo-cortical network. This effect does not seem to be correlated with the therapeutic efficacy of KD, but rather to low-calorie intake. Significance: Our results imply that consuming a restricted amount of calories could alter the balance between central excitation and inhibition in migraine.