Rhythmic ictal nonclonic hand (RINCH) motions in general EMU patients with focal epilepsy

Abstract Background Automatisms are frequently encountered during video-monitoring of patients with focal epilepsy in the EMU and generally thought to have a low lateralizing value in isolation. Rhythmic ictal nonclonic hand (RINCH) motions have been described in small series as a potentially lateralizing semiologic sign. We aimed to expand on prior work and determine the prevalence, characteristics, and lateralizing value of RINCH motions in general epilepsy monitoring unit (EMU) population with focal epilepsy. Methods All patients with recorded seizures in the EMU were included in our database search. Search was performed to identify seizures with reported RINCH motions. Both electroencephalography (EEG) and video of identified seizures were reviewed. Results We identified RINCH motions in 131 seizures in 71 patients. Overall seizure localization was temporal in 57 patients, frontotemporal in 3 patients, and extratemporal in 7 patients. We estimated RINCH motions to occur in 8.5% of EMU patients with recorded seizures. The most common RINCH motions in descending order were as follows: hand opening and closing, finger rubbing, milking motions, finger flexion/extension, and pill rolling. The mean RINCH motion latency from seizure onset was 34.48 s in temporal lobe epilepsy and 10.31 s in frontal lobe epilepsy. The RINCH motions were contralateral to seizure onset in 61 of 65 (93.8%) with lateralized seizure onset. Dystonic posturing was present in 43% of seizures with RINCH motions. Conclusion The RINCH motions are a common sign in focal seizures and should be distinguished from other types of manual automatism as they carry a strong lateralizing value.