Supernumerary phantom limb as a rare symptom of epileptic seizures—case report and literature review

Abstract

SUMMARYSupernumerary phantom limbs, that is, the awareness of an illusory extra limb is a fascinating neurologic symptom that has been described in a number of neurologic diseases including stroke, spinal injury, and epilepsy. Herein we report a case of a 70-year-old male patient with newonset focal seizures with left-sided supernumerary phantom arm and leg as the only seizure manifestation. Ictal single-photon emission computed tomography (SPECT) revealed a hyperperfusion in the right temporoparietal junction and allowed localization of the seizure-onset zone. This report is accompanied by a discussion of phenomenology and terminology in the context of existing literature. KEY WORDS: Supernumerary phantom limb, Epileptic seizure, Parietal lobe epilepsy, Ictal SPECT, Corporal awareness, Body schema.The term ''supernumerary phantom limb'' (SPL) describes the awareness of an illusory extra limb, in addition to the regular limbs. In earlier reports of the same symptoms the terms ''pseudo(poly)melia'' or ''reduplication of body parts'' have been used for the same phenomenon (Weinstein et al., 1954;Brugger, 2003). The symptom has been described in a variety of different neurologic disorders, right hemispheric stroke being the most common (Miyazawa et al., 2004). Case VignetteA 70-year-old male patient presented with new-onset attacks of ''the feeling to have an additional left arm and/or left leg.'' Figure 1 shows a sketch made by the patient beautifully demonstrating how he felt these supernumerary limbs in a position between his real limbs and the body. The patient further described that the additional limbs accompanied movements of his real limbs synchronously without disturbing his normal movements. Intentional movements with the phantom limbs only were not possible. The attacks occurred up to 10 times per day with duration of few minutes, showing a crescendo and decrescendo of the intensity of the sensation. The patient reported that he could feel but not see the additional limbs and was aware that this feeling was an illusion at all times. He reported no pain or thermal sensations in the phantoms but referred to a slight tingling. During the attacks he never lost consciousness and did not experience any accompanying symptoms. Reports from eyewitnesses confirmed that he seemed absolutely normal during the attacks. Otherwise the patient was in good health both physically and psychically without any relevant medical history or family history.Neurologic examination and extensive neuropsychological testing showed normal results. Repeated routine electroencephalography (EEG) and prolonged video-EEG monitoring did not reveal any epileptic activity during or in between attacks. Recorded attacks did not show any semiology, and ictal testing was utterly normal. Cerebrospinal fluid was normal. Cerebral high-resolution magnetic resonance imaging (MRI) showed very mild frontotemporal atrophy and slightly enlarged lateral ventricles but no focal pathology. Therefore, we performed an ictal technetium-hexamethylpropylene amine...

Birth and death of a phantom

“…The present case uniquely combines several features rarely reported in the literature. It is the fifth reported case of SPL with a paroxystic etiology, 14 and the first in an experimental TMS context with concomitant EMG recordings in a healthy person. As such, it provides a unique view on the genesis of SPL phenomena: for the first time, the very moment of SPL emergence could be pinpointed, revealing that SPL awareness can be almost sudden, unrelated to structural plasticity, very short-lasting (about 4 sec from birth to disappearance) and yet extraordinarily vivid.…”

“…Contrary to phantom limbs of the amputee or movement and postural illusions during sensorimotor impairment or cortical stimulation,6, 7, 8 SPLs entail a concomitant awareness of having an “extra” (illusory) limb and its physical counterpart (usually a plegic limb). The phenomenon has been observed following parietal strokes (predominantly in the right hemisphere)9 with severe sensorimotor impairment,10 as well as subcortical lesions,11 spinal cord injury,12 callosal and premotor damage,13 and has also been associated with seizures 14. Further, it can occur as a delusional belief15 or in clear‐minded patients,11 and cases vary widely along phenomenological characteristics such as motor and sensory features, sensitivity to visual and tactile feedback, or their experienced duration 4.…”

Experimental Inducibility of Supernumerary Phantom Limbs: A Series of Virtual Reality Experiments

“…While SPLs have been documented after stroke (Halligan et al, 1993;Srivastava et al, 2008;Khateb et al, 2009;Cipriani et al, 2011;Yoo et al, 2011), closed head injury (Rogers and Franzen, 1992), spinal cord injury (Curt et al, 2011), and during epileptic seizures (Millonig et al, 2011), their neurocognitive pathomechanisms remain unclear. Given that one essential mechanism of limb localization relies, among others, on the integration of efferent motor and afferent somatosensory signals, some consensus exists (Staub et al, 2006;Srivastava et al, 2008) that SPLs might result from a failure to integrate these two sources of information.…”

Post‐traumatic Visualized Supernumerary Phantom Limbs: A Case Presentation

“…Supernumerary phantom limbs (SPLs) are a rare neurological phenomenon in which a patient experiences additional phantom limb(s) [1]. SPLs have been described following a variety of neurological ailments, including stroke [1‐7], spinal cord injury (SCI) [1,8], epilepsy [1,9], traumatic brain injury (TBI) [1], space‐occupying lesion [1], cervical root avulsions [1], and demyelinating disease [1]. This experience is considered to be separate from psychiatric pathology; while SPLs are vividly experienced, the patients always clearly recognize that their SPLs do not actually exist in reality [1].…”