Phantom limb sensations in the ear of a patient with a brachial plexus lesion

Abstract

MP conducted the first neuropsychological evaluation on patient, study concept and design, acquisition of data, analysis and interpretation, writing and drafting of the manuscript, critical revision of the manuscript for important intellectual content. GG performed acquisition, analysis and interpretation of data, drafting of the manuscript, critical revision of the manuscript for important intellectual content. GG and MM performed acquisition of neurologic data. GL: performed the acquisition, analysis, interpretation and writing of EEG data. PH: analysis and interpretation of data, drafting of the manuscript, critical revision of the manuscript for important intellectual content. All authors read and approved the final manuscript. SummaryReferred phantom sensations are frequently reported following a peripheral injury. However, very few cases describe such sensations of the ear, and it remains unclear how the aural nerve territory can be remapped to one specific peripheral nerve region. We report on a patient with brachial plexus avulsion who underwent sensory testing and was asked to report the location of the

The Homuncular Jigsaw: Investigations of Phantom Limb and Body Awareness Following Brachial Plexus Block or Avulsion

“…This spatial specificity of referred sensation is fully compatible with the hypothesis of "somatotopic interferences" in the homuncular map of the somatosensory cortex. This possibility is strongly supported by the study of somatosensory-evoked potential [18]. In patients, stimulation within the vagally innervated territory of the external ear modulated activity within the centro-parietal regions, in accordance with the findings of previous studies [30 -32].…”

“…However, clinical observations of ear remapping after a traumatic nerve injury suggest that such sensations can be specific to the upper limb [35], fully compatible with the hypothesis of a collocation of ear contiguous to the upper limb in somatosensory cortical maps. More recently, a single case study on a patient who experienced a brachial plexus avulsion injury was undertaken to define and depict better the hand in the ear [18]. After brachial avulsion, the patient reported that phantom limb sensations in the hand and arm were evoked by stimulating the ear.…”

“…To conclude, we support an integrated view of the bottom-up and top-down contributions to the field of phantom sensations, body representations, and post-traumatic reorganization. A more detailed scientific understanding will require new experimental perspectives [54], including a wider range of clinical or artificially induced conditions [18,25] and a lucid theoretical reorganization of experimental results, as proposed by Brecht [43].…”

Disconnected Body Representation: Neuroplasticity Following Spinal Cord Injury

“…An assessment of the emergence and course of progression of phantom hand sensation after a brachial plexus injury in a patient enabled the investigation of an unclear aspect of the sensory somatotopic organization of the ear [50]. Typically, the phantom sensation of a missing or deafferented hand can be evoked by touching the corresponding cheek and lower part of the face, but, in the aforementioned patient, the phantom sensation was evoked via stimulation of the aural region innervated by a branch of the vagus nerve [6]. Interestingly, after a few weeks, the phantom sensation began to gradually migrate from the ear and generally localized on the lower part of the face, suggesting ongoing sensory reorganization [51].…”

“…Following input and output loss of limb BPA due to the traction/avulsion of cervical nerve roots from the spinal cord mimics the amputation, however, preserving the visual experience of the limb. Patients with BPA commonly report a remapping of sensation from the hand to the cheek [4], in the jaw and buccal region [5], or in the ear [6], presumably the same mechanisms that are responsible for phantom sensations in amputees. In SCI, the sensorimotor signaling between the brain and an entire portion of the body (and not only a specific limb) located below the level of lesion is interrupted permanently despite the physical body remaining unaltered.…”