THE CLINICAL AND THE ICTAL VIDEO-EEG CHARACTERISTICS OF 28 CASES WITH INFANTILE SPASMS

Objectives: Infantile spasms (IS) was generally divided into three types including in flexion, extension or mixed, but nothing more definitive was stated as to the duration, extent or mode of muscle contraction or associated ictal electroencephalographic changes. The aim of the study is to investigate the clinical interictal and ictal video-EEG characteristics of 28 cases with IS and evaluate the clinical significances for the early diagnoses and treatment.

Methods: Clinical observation and video-EEG monitoring were analyzed and followed up in 28 babies with IS.

Results: twenty-eight babies were diagnosed to be male in 19 cases and have IS by the clinical spasms and hypsarrhythmia at onset of the initial seizures in 2˜16 months with an average of 6.5 months of age. All cases were involved in the axial musculature with three generally divided types including in flexion, extension or mixed by 12, 9 and 7 cases respectively. According to analyzing 64 times of clinical spasms and video-EEG recordings in all babies, the spasms patterns of this group were clinically classified as follows: symmetric spasms in 14 cases, asymmetric/asynchronous spasms in 8 cases, focal or hemispasms in 6 cases, spasms combined with partial seizures in 8 cases, spasms preceded by brief atonia in 2 cases, subclinical spasms in 5 cases; in addition, subtle spasms were found alone or coexistence with most of cases. Interictal EEG showed the typical and atypical hypsarrhythmia in 8 and 20 cases respectively, focally poly-spike/sharp and slow waves or hemihypsarrhythmia in 5 cases; at least three different patterns of ictal-EEG were associated with clinical spasms: fast wave bursts, diffuse polyphasic high slow voltage wave complex and desynchronization or decremental activity, in which the prominent positivity of the polyphasic high voltage slow wave complex of negative-positive- negative deflection was usually parallel with clinical tonic or tonic spasms; Video-EEG monitoring was more valuable than the routine EEG for the early diagnosis and treatment of IS, particularly in those babies with history of hypoxic-ischemic encephalopathy and subclinical spasms. Although most of the clinical spasms were usually symmetric, focal lesions could not be excluded. EEGs were not surely synchronous and symmetric.

Conclusion: IS was a special type of epileptic seizures as well as an epileptic syndrome with different patterns and could be associated with partial and other types of seizures; video-EEG was much more valuable to its early diagnosis and treatment.