Rhythmic Ictal Nonclonic Hand (RINCH) Motions: A Distinct Contralateral Sign in Temporal Lobe Epilepsy

Authors


Address correspondence and reprint requests to Dr. B. Abou-Khalil at 2311 Pierce Ave, Room 2224, Nashville, TN 37232, USA. E-mail: bassel.abou-khalil@vanderbilt.edu

Abstract

Summary: Purpose: To describe a new ictal sign in temporal lobe seizures—rhythmic ictal nonclonic hand (RINCH) motions and to determine its lateralizing significance and other ictal manifestations associated with it.

Methods: We identified 15 patients with temporal lobe epilepsy who demonstrated RINCH motions and reviewed video-EEG recordings of all their seizures. We analyzed the epilepsy characteristics and all clinical features of recorded seizures, with particular attention to RINCH motions.

Results: RINCH motions were unilateral, rhythmic, nonclonic, nontremor hand motions. RINCH motions were usually followed by posturing, sometimes with some overlap. They involved the hand contralateral to the temporal lobe of seizure onset in 14 of 15 patients.

Conclusions: RINCH motions are a distinct ictal sign that could be considered a specific type of automatism. They appear to be a lateralizing contralateral sign and are associated with dystonic posturing in temporal lobe epilepsy.

Accurate localization of the epileptogenic zone is essential for successful epilepsy surgery. Although many tests contribute to the final localization, seizure semiology plays an important role in localization and lateralization (Kotagal et al., 1995; Kramer et al., 1997). The majority of patients seen for epilepsy surgery have temporal lobe epilepsy (TLE). In many patients with TLE, lateralization of the seizure focus is the major challenge, particularly when bilateral EEG abnormalities are in evidence. Dystonic posturing is one of the most reliable lateralizing signs in TLE, being contralateral to the hemisphere involved in the seizure activity. Manual automatisms have generally been regarded as lacking lateralizing significance, except when associated with dystonic posturing, which tends to inhibit or mask automatisms in the affected extremity (Serles et al., 1998; Kotagal, 1999). It is possible that the classification of automatisms so far has been too broad and that some movements classified as automatisms may be distinct in their characteristics.

We observed distinctive nonclonic unilateral rhythmic hand (RINCH) motions during seizures in several patients with TLE undergoing seizure monitoring. We initially considered these rhythmic hand movements to be automatisms, but noted they were contralateral to the seizure focus. We studied these RINCH motions systematically in a consecutive series of patients.

METHODS

After our initial observation of RINCH motions, we identified 15 patients with epilepsy who demonstrated these motions and reviewed the video recordings of all their seizures. We recorded time of clinical and EEG onset, time and duration of the rhythmic motions, specific character and laterality of these motions, and association with other ictal signs. We recorded the proportion of seizures that involved RINCH activity. We reviewed the results of the presurgical evaluation and in particular recorded the localization and laterality of the seizure focus. All patients had video-EEG monitoring with antiepileptic drug (AED) discontinuation.

Based on the total number of seizures recorded, we estimated the incidence of RINCH in seizures of affected patients. We also surveyed the population of patients with TLE evaluated during the period that the patients with RINCH were identified, to estimate the incidence of RINCH in TLE.

The study was approved by the Vanderbilt Institutional Review Board.

RESULTS

The RINCH motions varied between patients but were consistent in each patient. They were low-amplitude milking, grasping, fist clenching, or pill rolling, or larger-amplitude opening–closing motions (Table 1). A description common to all patients would be that RINCH motions were unilateral, rhythmic, nonclonic motions. They were different from tremor, in that they were slower and more complex than most tremors. In addition, they were often associated with a more forceful contraction than is seen with tremor.

Table 1. Demographics, epilepsy/seizure data, and characteristics of RINCH motions in affected patients. 
Patient no.GenderAge (yr)RINCH descriptionRINCH sideRINCH duration (s)Associated signs (after RINCH)No. seizures with RINCH/ total seizures
 1F45Repetitive grasping motions with fingers rubbing palm, starting with the 5th digit and followed immediately in succession by the fourth, third, and second digitsR9–16 (mean, 11.5)Fist clenching/wrist posturing4/4
 2M22Repetitive grasping (fingers repetitively flex into a fist, then extend)L7Dystonic posturing1/13
 3M26Repetitive grasping (fingers repetitively flex into a fist, then extend)R15Fist clenching (likely subtle posturing)1/4
 4F9Repetitive pill rolling of thumb and fingersR18–35 (mean, 23)Tonic posturing3/4
 5F36Repetitive grasping (fingers repetitively flex into a fist, then extend)R28Dystonic posturing1/14
 6F44Repetitive grasping motions with fingers rubbing palm, starting with the 5th digit and followed immediately in succession by the fourth, third, and second digitsR37–38 (mean, 37.5)Tonic posturing2/8
 7F51Repetitive grasping (fingers repetitively flex into a fist, then extend)R6–36 (mean, 11)Dystonic or tonic posturing8/12
 8M30Repetitive pill rolling of thumb and fingersR9Tonic posturing1/5
 9F28Repetitive flexion and extension of fingersR57–128 (mean, 92.5)Tonic posturing2/3
10F38Repetitive flexion and extension of the index finger followed by repetitive flexion and extension of all fingersR37Tonic posturing1/8
11M41Repetitive opening and closing of the hand, starting with the fifth digit and followed by rhythmic succession of the fourth through the first digit in a fanning motionL19Dystonic posturing1/2
12M34Repetitive rubbing of fingers on palm, followed by fist squeezingR27–29 (mean, 28)Tonic posturing2/6
13M24Repetitive flexion and extension of fingersL8Dystonic posturing1/3
14M33Repetitive squeezing of fist and repetitive pill rolling of thumb and fingersL3/R1a7–43 (mean, 24.5)Dystonic or tonic posturing4/21
15M30Repetitive rubbing of fingers on palm, followed by fist squeezingR8–32 (mean, 20)Dystonic posturing2/13
Patient no.Focus localization/ lateralityMRI findings/ pathologySurgery: surgical outcome (FU duration)
  1. B, bilateral; R, right; L, left; MTS, mesial temporal sclerosis.

  2. aRINCH was on the left in three seizures, on the right in one.

 1LL MTSNo surgery because of failed Wada memory testing
 2B (R for RINCH seizures)L MTSL temporal lobectomy despite bilateral foci: no worthwhile improvement (4 yr)
 3LL temporal cortical dysplasiaL temporal lobectomy: seizure free (3 mo)
 4RNormalR temporal lobectomy: seizure free (5 mo)
 5LL MTSL selective amygdalohippocampectomy: seizure free (3 yr)
 6LL MTSL selective amygdalohippocampectomy: seizure free (1 yr)
 7LL MTSL selective amygdalohippocampectomy: seizure free (1.5 yr)
 8LL MTSL selective amygdalohippocampectomy: seizure free (1 yr)
 9LLeft midposterior temporal encephalomalaciaNo surgery
10LL MTSL selective amygdalohippocampectomy: seizure free for 7 mo, then recurrence with no worthwhile improvement now (2 yr)
11B (R for RINCH seizures)NormalNo surgery
12LL MTSL selective amygdalohippocampectomy: seizure free (1 yr)
13B (R for RINCH seizures)NormalNo surgery
14B (R for RINCH seizures)L MTSNo surgery
15B (L for RINCH seizures)L MTSNo surgery

The mean duration of the motions was 24 s, with a range of 6–128 s. RINCH motions occurred 0–79 s (mean, 24.7 s) after the onset of the electrographic seizure and 0–58 s (mean, 16.5 s) after the onset of the clinical seizure. RINCH motions were seen within 5 s of clinical seizure onset in eight (24%) of 34 involved seizures and within 10 s in 15 (44%) of 34 seizures (in six and seven patients, respectively).

RINCH motions were followed by posturing (dystonic or tonic) in every patient (although not in every seizure). The posturing usually started after the RINCH motions ended, but occasionally started before they ended. RINCH motions involved the hand contralateral to the temporal lobe of seizure onset in 14 of 15 patients. In the single patient who demonstrated rhythmic hand movements ipsilateral to the seizure onset (Table 1, patient 4), dystonic posturing became bilateral, consistent with contralateral seizure spread. In one patient with bilateral independent seizure onsets, RINCH motions were usually contralateral to the seizure onset (Table 1, patient 14). Posturing did not follow RINCH motions in six of the 34 seizures, and in one seizure, the affected hand went out of camera range right after the RINCH motions.

Interestingly, RINCH motions affected the right hand in 28 (82%) of 34 seizures and 11 of 14 patients (one patient demonstrated independent right- and left-hand involvement) and were most often associated with left mesial temporal sclerosis. Whereas we did not specifically review and record automatisms in general, we did observe that picking and fumbling automatisms sometimes occurred simultaneously with RINCH motions, but tended to affect the opposite extremity.

All patients with RINCH motions had TLE (Table 2). In the 15 patients studied, RINCH motions were noted in 34 of 120 seizures analyzed. For each individual, the proportion of seizures with these rhythmic hand movements ranged from 7 to 100%. Based on a survey of patients admitted with TLE around the time that RINCH motions were identified, we estimated that RINCH motions occur in about 10% of patients with TLE.

Table 2. Features that discriminate RINCH motions from other extremity automatisms
FeaturesRINCHOther extremity automatisms
Body part involvedFingers and handAny extremity; proximal aspect of extremity(ies) often involved
RepetitionRhythmicOften arrhythmic (but may be rhythmic)
AmplitudeLowOften large amplitude
PatternRhythmic milking, grasping, fist clenching, pill rolling, or opening–closingVariable, but often picking, fumbling, or large-amplitude motions
LateralizationContralateral to seizure focusBilateral or ipsilateral
Association with other signsOften precedes or is associated with dystonic posturingInhibited by dystonic posturing; will persist contralateral to the side of posturing

DISCUSSION

We have identified a distinct ictal motor sign in TLE that is contralateral to the side of seizure activity. RINCH movements typically precede dystonic or tonic posturing and involve the posturing extremity. RINCH motions may be a useful lateralizing sign, particularly in that they are an early sign and tend to precede dystonic posturing. They were usually the first lateralizing sign when they were present. Early signs are more reliable because they are more likely to precede contralateral seizure spread. In the population that we studied, RINCH motions were consistently contralateral to the focus, except in one patient who also had bilateral dystonic posturing. This suggested that seizure activity had spread to the contralateral hemisphere in that patient. In the presence of bilateral dystonic posturing, or other signs of rapid contralateral seizure spread, RINCH motions may not be totally reliable in their lateralizing value. In the absence of bilateral dystonic posturing, RINCH motions were a lateralizing sign in the patients that we evaluated. However, this finding has to be confirmed in patients who became seizure free with epilepsy surgery. Additionally, as with any other seizure sign, RINCH motions should not be used in isolation, but rather in concert with other signs.

No evidence was found in a literature review that RINCH motions were recognized in studies of TLE seizure semiology. If they were noted in these studies, they were likely to have been classified as plain automatisms. In TLE, extremity automatisms seem to be of lateralizing value only in the presence of dystonic posturing (Kotagal et al., 1995; Serles et al., 1998; Williamson et al., 1998; Kotagal, 1999). In that setting, the automatisms are ipsilateral, whereas the contralateral extremity is affected with dystonic posturing (Fakhoury et al., 1994). Before the onset of posturing, automatisms are often bilateral (Fakhoury et al., 1994; Kotagal, 1999). The presence of unilateral automatisms will therefore suggest that the focus is ipsilateral. This is where the recognition of RINCH motions will be extremely valuable, as these are typically contralateral. Recognizing RINCH motions will make their contralateral localization supportive rather than problematic for presumed focus lateralization. Based on the example of RINCH motions, further subclassification of automatisms in general may improve their value in seizure localization and lateralization.

The mechanism underlying RINCH motions is unclear. Patients occasionally look at their extremity as they are engaging in RINCH motions. One speculation could be that RINCH motions are triggered by a sensory experience in the affected hand. However, no patients reported any sensation in the hand as a component of the seizure. If RINCH motions are a response to a sensory experience, they must occur in the presence of altered awareness or amnesia. The association of RINCH motions with dystonic posturing raises the possibility of a common pathophysiology. Ictal dystonia is most probably related to involvement of the basal ganglia in the seizure discharge, particularly the putamen (Newton et al., 1992; Dupont et al., 1998; Joo et al., 2004; Mizobuchi et al., 2004). RINCH motions preceded dystonic posturing, and therefore may be an early sign of basal ganglia involvement, but such a conclusion would require further investigation. Evidence exists of a sensory role for the basal ganglia, particularly the putamen (Kaji, 2001).

The findings of the current study should be confirmed with a prospective investigation of patients undergoing epilepsy presurgical evaluation. Understanding of the mechanism underlying RINCH motions may be advanced with ictal SPECT, which has been helpful in the physiology of dystonic posturing (Newton et al., 1992; Joo et al., 2004; Mizobuchi et al., 2004). Studying RINCH motions in patients with implanted electrodes may also be helpful in evaluating associated cortical ictal activity.

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