Polysomnographical assessment of the pathophysiology of West syndrome

The Moro reflex: insights into the pathophysiology of generalized tonic‐clonic seizures and infantile spasms

“…Similarly, studies in animal models have demonstrated that the pontine reticular formation is crucial in the generation and expression of tonic convulsions, as bilateral lesions of the pontine tegmentum involving the superior cerebellar peduncles and the nucleus reticularis pontis oralis can attenuate the tonic components of generalized seizures, without effect on clonus [25]. Similarly, it has been hypothesized that a functional disturbance of the pontine tegmentum plays a role in the pathophysiology of infantile spasms [26]. In these seizure types, the activation of the same neural circuitry involved in the MR could occur through either direct excitation or through an indirect “liberating” mechanism, secondary to epileptic disruption of cortical inhibitory control on subcortical structures [18, 27].…”

“…Epileptic spasms usually last 1-2 seconds and therefore have a duration that is intermediate between myoclonic jerks (which last milliseconds) and tonic seizures (which last > 2 seconds). Of note, the bilateral proximal massive movements of epileptic spasms are sometimes reminiscent of the symmetrical extension and abduction movements observed with the MR [15][16][17][18][19], particularly in the case of extensor epileptic spasms (video 2). Interestingly, it has been hypothesized that the same brainstem circuitry is involved in the generation of both phenomena [17,18].…”

“…Of note, the bilateral proximal massive movements of epileptic spasms are sometimes reminiscent of the symmetrical extension and abduction movements observed with the MR [15][16][17][18][19], particularly in the case of extensor epileptic spasms (video 2). Interestingly, it has been hypothesized that the same brainstem circuitry is involved in the generation of both phenomena [17,18]. However, as shown in a detailed video-polygraphic study, epileptic spasms are characterized by a complex pattern of muscular activation, which despite clinical similarity, is markedly heterogeneous and difficult to explain in terms of cortical or reticular generators [20].…”