Semiological value of rhythmic ictal non-clonic hand (RINCH) motions in epileptic seizures

Abstract

Objective

To study the semiological significance of rhythmic ictal non-clonic hand (RINCH) motions in epileptic seizures, as observed in prolonged video-EEG monitoring (VEM).

Material and methods

Retrospective observational study of patients with epilepsy admitted for prolonged VEM between 2020 and 2024, who exhibited RINCH motions during recorded seizures. Electroclinical data were collected and analysed, focusing on the duration and associated semiology of RINCH motions.

Results

Among 379 patients admitted for VEM, RINCH motions were observed in 12 (66.6% male, mean age [standard deviation], 44.7 [11.3] years). All patients were right-handed. Seizure onset occurred in the temporal lobe in 10 cases (83.3%) and left hemisphere in 11 (91.6%). Aetiology was structural in 9 patients (75%), unknown in 2 (6,7%), and autoimmune in 1 (8.3%).

All seizures were associated with impaired awareness and automatisms. Ictal or postictal language impairment were observed in 9 patients (75%). Only one case progressed to bilateral tonic-clonic seizure. RINCH motions involved the right hand in all seizures, and in one case spread to the contralateral hand. These movements appeared within a median of 25 seconds (Q₁–Q₃, 12–90) after clinical onset, with a median duration of 19 seconds (Q₁–Q₃, 11−48). EEG onset occurred after clinical onset in 7 cases (58.3%), and was consistently observed over the left anterior temporal region, except for one case with a parietal origin.

Conclusion

RINCH motions represent an uncommon but distinctive manifestation of epileptic seizures, often accompanied by impaired awareness, automatisms and aphasia. These movements typically occur in the hand contralateral to the seizure onset zone. The most frequent seizure onset localisation is the left temporal lobe (dominant) in right-handed patients.

Resumen

Objetivo

Estudiar la importancia semiológica de los movimientos ictales rítmicos no clónicos de la mano (RINCH) en las crisis epilépticas, tal como se observan en la monitorización vídeo-EEG prolongada (mVEEG).

Material y métodos

Estudio observacional retrospectivo de pacientes con epilepsia ingresados para mVEEG prolongada entre 2020 y 2024, que presentaron RINCH durante las crisis epilépticas registradas. Se recopilaron y analizaron datos electroclínicos, centrándose en la duración y la semiología asociada de los RINCH.

Resultados

De 379 pacientes ingresados ​​para mVEEG, se observó RINCH en 12 (66,6 % varones, edad media de 44,7 ± 11,3 años). Todos los pacientes eran diestros. El inicio de la crisis se produjo en el lóbulo temporal en 10 casos (83,3 %) y en el hemisferio izquierdo en 11 (91,6 %). La etiología fue estructural (n = 9; 75 %), desconocida (n = 2; 6,7 %) y autoinmune (n = 1; 8,3 %).

Todas las crisis cursaron con alteración de la consciencia y automatismos. Se objetivó alteración del lenguaje crítica o postcrítica en nueve casos (75%). Solo un caso tuvo una evolución a tónico-clónica bilateral. El movimiento de RINCH fue con la mano derecha en todas las crisis y, en un caso se propagó a la mano contralateral. Estos movimientos aparecieron en una mediana de 25 segundos (RIC 12-90) tras el inicio clínico, con una duración media de 19 segundos (RIC 11-48). El inicio EEG se detectó tras el inicio clínico en siete casos (58,3%), y fue de forma consistente en la región temporal anterior izquierda, excepto en un caso parietal.

Conclusión

Los movimientos RINCH representan una manifestación infrecuente, pero distintiva, de las crisis epilépticas, a menudo acompañada de alteración de la consciencia, automatismos y afasia. Estos movimientos suelen ocurrir en la mano contralateral a la zona de inicio de la crisis. La localización más frecuente de inicio de las crisis es el lóbulo temporal izquierdo (dominante) en pacientes diestros.

Introduction

The identification of semiological features of focal epileptic seizures that may assist in lateralising and locating the seizure onset zone and epileptogenic area is crucial to accurately characterise seizures.

Automatisms are a type of motor manifestation in focal seizures, characterised by the presence of automatic, stereotyped actions without clear intentionality, such as object manipulation or chewing movements. These repetitive movements may involve a wide variety of behaviours, ranging from simple movements to more complex actions. The most frequent automatisms include oral, gestural, and ambulatory movements. However, they may also involve a broader range of complex motor movements involving different parts of the body. Unilateral automatisms of the upper limbs have generally been considered to lack lateralising value, except when they are associated with contralateral dystonic posture.^1–3

Rhythmic ictal non-clonic hand (RINCH) motions are an ictal semiological sign associated with temporal lobe epilepsy (TLE). They were first described in 2006 by Lee et al.⁴ as unilateral, rhythmic, non-clonic movements without tremor (eg, low-amplitude milking movements, grasping, fist-clenching, pill rolling, or larger-amplitude hand opening and closing), generally concomitant with or followed by dystonic postures.¹

RINCH motions are considered a type of automatism and are thought to be a lateralising sign contralateral to the epileptogenic focus, appearing after the propagation of ictal activity beyond the temporal lobe,⁵ especially to contralateral frontal regions (orbitofrontal cortex and anterior cingulate gyrus), with subsequent activation of premotor and supplementary areas, generating a unilateral rhythmic motor pattern; however, little evidence is available on the subject. Their frequent association with ictal dystonia is interpreted as the extension of ictal activity towards cortico-striato-pallido-thalamic circuits, involving the putamen and other structures of the basal ganglia, responsible for sustained postures.^4,5

The objective of this study is to analyse and describe the electroclinical characteristics of this sign in epileptic seizures during video-EEG monitoring (VEM), contributing further knowledge into its potential localising relevance.

Material and methods

An electronic search was conducted using the keyword “RINCH” in the repository of the epilepsy monitoring unit (EMU) of a tertiary-level hospital, filtering for all VEM reports of patients with epilepsy admitted between 2020 and 2024 for prolonged VEM.

All patients underwent clinical assessment prior to admission to the EMU; their demographic (age, sex, race) and clinical characteristics (age at epilepsy onset, dominant hand, aetiology, epilepsy localisation and lateralisation, antiseizure medications) were gathered retrospectively. Subsequently, we reviewed the video-EEG studies of all eligible patients to gather and analyse data. We analysed the number of seizures recorded and the number of seizures with RINCH motions; the sequence of symptoms during the seizure, according to the classification proposed by Lüders et al.⁶; presence of impaired awareness; type of motion, lateralisation, and duration of RINCH motions; time from seizure onset to appearance of RINCH motions; clinical duration of the seizure; progression to bilateral tonic-clonic seizure; presence/duration of the post-ictal period; localisation at EEG onset; and propagation, and whether the electrical change was prior or subsequent to clinical onset. VEM was conducted using a 32-lead EEG system (Medical Inc.; Pleasanton, CA) with electrodes placed on the scalp according to the international 10-20 system. We conducted a descriptive analysis of clinical and video-EEG findings.

The study was approved by the clinical research ethics committee of Hospital Universitario Vall d’Hebron, (protocol no. PR(AG)663/2020), and complies with the principles of the Declaration of Helsinki. As this is a retrospective, observational study based on clinical and video-EEG records obtained previously, patients underwent no additional intervention beyond normal clinical practice. All participants included in the study gave written informed consent at the time of admission for prolonged monitoring.

Statistical analysis was performed using the SPSS statistics software, version 25.0. Categorical variables are expressed as number (percentage), and numerical variables as mean (standard deviation [SD]), or as median (quartiles 1 and 3 [Q₁–Q₃]) if they were not normally distributed.

Results

Of a total of 379 patients undergoing VEM in the study period, RINCH motions were reported in 12 (3%). Among patients with drug-resistant TLE, these patients accounted for 9.9% (12/121). Mean age of the sample was 44.7 (11.3) years; 8 patients (66.7%) were men. Mean age at epilepsy onset was 29.9 (15.3) years, with a mean disease duration of 17.5 (17.5) years.

All patients presented focal epilepsy; the epileptogenic zone was located in the temporal lobe in 10 patients (83.3%) and was multifocal in 2 (16.7%). Seizures began in the left hemisphere in all but one of the patients. Aetiology was structural in 9 patients, unknown in 2, and autoimmune in one. Demographic and clinical characteristics are summarised in Table 1.

Table 1.

Demographic data and epilepsy characteristics of patients admitted to the epilepsy monitoring unit for prolonged video-EEG monitoring and presenting RINCH motions during seizures.

	Results (n = 12)
Demographic characteristics
Men, n (%)	8 (66.6)
Age in years, mean (SD)	44.7 (11.3)
Epilepsy characteristics
Age at onset (years), mean (SD)	29.9 (15.3)
Dominant hand (right), n (%)	12 (100)
Type (focal), n (%)	12 (100)
Aetiology:
Structural, n (%)	9 (75)
Mesial TLE	4 (33.3)
Vascular	2 (16.7)
Tumour	2 (16.7)
Post-traumatic	1 (8.3)
Unknown, n (%)	2 (16.7)
Autoimmune, n (%)	1 (8.3)
Localisation (temporal lobe), n (%)	10 (83.3)
Lateralisation (left hemisphere), n (%)	11 (91.7)

RINCH: rhythmic ictal non-clonic hand; SD: standard deviation; TLE: temporal lobe epilepsy.

In the 12 patients included, a total of 36 seizures (mean, 3 [1.95]) were recorded, with RINCH motions appearing in 23 (mean, 1.92 [1.16]). Seizure semiology was comparable in all patients, with all participants presenting focal onset with impaired awareness. Aura was absent in 8 patients. Motor phenomena were not observed at onset in 9 patients. RINCH motions manifested as a sign of seizure progression, associated with automatisms, in all patients except one, in whom complete recording was not possible; in this case, we were only able to identify impaired awareness and behaviour arrest associated with RINCH motions. RINCH motions were characterised as pill-rolling in 41.6% of cases, grasping in 16.6%, wrist rotation in 16.6%, milking in 8.3%, fist-clenching in 8.3%, and flexion/extension of the first finger in 8.3%. They were associated with ipsilateral dystonia in 4 patients (33.3%), which occurred after RINCH motions in all cases. Language impairment was observed in 9 patients (75%), and occurred after RINCH motion onset, either during seizure progression or in the post-ictal period. Only one patient presented progression to bilateral tonic-clonic seizure. Two seizures occurred during sleep. The sequence of semiological events in each patient is shown in Table 2. An example of RINCH motion is shown in Video. 1.

Table 2.

Chronological sequence of semiological events in our patients.

	Symptom 1	Symptom 2	Symptom 3	Symptom 4
Patient 1	Impaired awareness	Simple vocalisations	RINCH motions
Patient 2	Impaired awareness	Blinking and hand automatisms	RINCH motions	Dystonia
Patient 3	Impaired awareness	Hand and oromandibular automatisms + aphasia	RINCH motions	Dystonia
Patient 4	Impaired awareness	Aphasia + oral automatisms	RINCH motions	Dystonia
Patient 5	Impaired awareness	Behaviour arrest	RINCH motions	–
Patient 6	Seeking movement of the head	Sudden change in facial expression	RINCH motions	–
Patient 7	Behaviour arrest	Oromandibular automatisms	RINCH motions	–
Patient 8	Behaviour arrest	Aphasia + nose-wiping	RINCH motions	Dystonia
Patient 9	Behaviour arrest	Aphasia	RINCH motions	–
Patient 10	Behaviour arrest	RINCH motions	Ictal whistling	–
Patient 11	Behaviour arrest	Pedalling + automatisms	RINCH motions	Aphasia
Patient 12	Pedalling + RINCH motions	Forced smile	RINCH motions	Axial tonic contraction

RINCH: rhythmic ictal non-clonic hand.

All patients were right-handed, and RINCH motions involved the right hand in all cases. In one case, RINCH motions extended to the contralateral hand. Mean seizure duration was 205.7 (274.5) seconds. RINCH motions appeared a median of 25 (Q₁-Q₃, 12-90) seconds after clinical onset, and had a median duration of 19 (11-48) seconds. Seizure onset occurred in the left anterior temporal lobe in 10 cases, and the left parietal lobe in one. In one seizure, it was not possible to precisely locate the region of onset on EEG due to myograph artefacts. A noteworthy finding in the seizure with parietal onset is a longer time from clinical onset to RINCH motion onset (759 seconds), with RINCH motion duration being shorter (9 seconds). Seizures originating in the left anterior temporal region spread to ipsilateral frontal regions in 10 cases, whereas another temporal lobe seizure presented minimal propagation to adjacent areas. The seizure originating in the left parietal lobe spread to the ipsilateral temporo-occipital area. Seizure characteristics are summarised in Table 3. Fig. 1 shows a representative example of an EEG from one of the patients, illustrating the typical patterns associated with seizures originating in the temporal lobe.

Table 3.

Characteristics of epileptic seizures and RINCH motions in patients attended at the epilepsy monitoring unit for prolonged video-EEG monitoring.

	Results (n = 12)
Seizure characteristics
Type (focal onset with impaired awareness), n (%)	12 (100)
Onset (non-motor), n (%)	9 (75)
During wakefulness, n (%)	10 (83.3)
Clinical duration (seconds), mean (SD)	205.7 (274.5)
Language impairment, n (%)	9 (75)
Impaired awareness, n (%)	12 (100)
No aura, n (%)	8 (66.6)
No progression to BTCS, n (%)	11 (91.7)
Bioelectric change after clinical onset, n (%)	7 (58.3)
Bioelectric onset in the left anterior temporal lobe, n (%)	10 (83.3)
RINCH motion characteristics
Duration (seconds), median (Q1-Q3)	19 (11-48)
Latency after seizure onset (seconds), median (Q1-Q3)	25 (12-90)
Hand involved (right), n (%)	12 (100)

BTCS: bilateral tonic-clonic seizures; Q₁-Q₃: quartiles 1 and 3; RINCH: rhythmic ictal non-clonic hand; SD: standard deviation.

Figure 1.

Surface EEG study showing the onset of a seizure with RINCH motions in a patient with tumoural structural epilepsy secondary to left parahippocampal cavernoma. The study was performed prior to lesionectomy. Top: monopolar montage with average reference. Bottom: longitudinal bipolar montage. Both traces show rhythmic theta activity in left temporal electrodes (F7, T7, P7). Low-frequency filter: 0.5 Hz, high-frequency filter: 70 Hz; notch filter: 50 Hz; sensitivity: 10 µV/mm, time base: 30 mm/s.

Of the 11 patients with RINCH motions and left focal TLE identified with surface video-EEG, 4 underwent resective surgery (2 with mesial TLE, one with parahippocampal cavernoma, and one with non-lesional aetiology). The median follow-up time after surgery was 14 months (Q_1-Q₃: 13-21). Three patients are currently seizure-free, and another patient with structural epilepsy secondary to mesial TLE presented episodes with atypical semiology suggestive of non-epileptic paroxysmal events, although the diagnostic process is not yet complete.

Discussion

In this study, RINCH motions are described as an ictal sign that may be considered an automatism with semiological value, lateralising seizure onset in the contralateral hemisphere; this is consistent with previous studies.^4,5,7 In our series, RINCH motions invariably affected the right hand, contralateral to the region of seizure onset, which was preferentially left-sided (dominant hemisphere); previous case series also report that RINCH motions are more frequent in seizures originating in the left hemisphere.⁴ Greater evidence is needed on the preferential involvement of the dominant hemisphere, as this may have been due to bias resulting from our study’s small sample size.

In addition to RINCH motions, the seizures described presented the typical ictal characteristics of temporal lobe seizures, such as impaired awareness, language impairment (when the dominant hemisphere is involved), and oroalimentary automatisms. Generally, EEG revealed onset in the left anterior temporal region, with subsequent propagation to frontal regions.⁶

Our findings suggest that non-temporal regions also play an important role. In 82% of cases, ictal activity spread to ipsilateral frontal regions, supporting the hypothesis that frontal lobe activation may be a determinant of the appearance of RINCH motions, as suggested in the literature. Furthermore, it has been suggested that activation of the basal ganglia plays a key role in the generation of these movements,⁵ which may explain their association with dystonic postures; it was not possible to test this hypothesis in our study as the data are from surface EEG.

A previous study by Kuba et al.,⁷ using invasive EEG monitoring, showed that RINCH motions appeared more frequently in seizures originating in the anterior temporal lobe, with ictal activity spreading to the medial and orbitofrontal cortex prior to RINCH motion onset. This phenomenon may be explained by the propagation of ictal activity from inferomedial temporal regions, including the amygdala and hippocampus, towards the frontal lobe through such anatomical pathways as the uncinate fasciculus and cingulate cortex.

The participation of the frontal lobe may also explain some of the associated clinical symptoms, such as the language impairment observed in our study, particularly in seizures affecting the dominant hemisphere. Although frontal lobe involvement is a possible explanation for this, these alterations may also derive from basal or polar temporal involvement in temporal-onset seizures.⁸ The premotor cortex and supplementary motor area participate in the generation of repetitive, stereotyped motor patterns, and in modulating rhythmic movements. The association with dystonic postures may be explained by the involvement of the supplementary motor area and fronto-striatal connections.⁹ This relationship has previously been documented and suggests that detection of RINCH motions may be an indirect sign of frontal propagation.¹⁰

In other published series, RINCH motions are reported in approximately 10% of seizures in patients with drug-resistant TLE. Among patients admitted to our EMU, 32% had drug-resistant TLE, with 9.9% presenting RINCH motions. Therefore, RINCH motions represent an infrequent but highly informative semiological sign in the context of focal epilepsy.

This study presents certain limitations, including its retrospective design and relatively small sample size. A significant limitation is the fact that both localisation and lateralisation of seizures were established using surface electrodes, which present limitations compared to invasive EEG studies.¹¹ Future studies with larger patient samples, prospective designs, and using invasive EEG or functional neuroimaging may help to more precisely identify the anatomical substrate associated with RINCH motions.

Conclusion

Our results suggest that RINCH motions are a rare manifestation of epileptic seizures, with a tendency to present in seizures involving the left temporal lobe, characterised by impaired awareness, contralateral automotor semiology, and language impairment in right-handed patients. These movements should be considered a meaningful sign on account of their simple recognition and high localising value.

Funding

This study has received no funding from any public, private, or non-profit organisation.