Palinacousis leading to the diagnosis of temporal lobe seizures in a patient with schizophrenia

Localizing and lateralizing value of auditory phenomena in seizures

BACKGROUND

Auditory seizures (AS) are a rare type of focal seizures. AS are classically thought to involve a seizure onset zone (SOZ) in the temporal lobe, but there remain uncertainties about their localizing and lateralizing value. We conducted a narrative literature review with the aim of providing an up-to-date description of the lateralizing and localizing value of AS.

METHODS

The databases PubMed, Scopus, and Google Scholar were searched for literature on AS in December 2022. All cortical stimulation studies, case reports, and case series were analyzed to assess for auditory phenomena that were suggestive of AS and to evaluate if the lateralization and/or localization of the SOZ could be determined. We classified AS according to their semiology (e.g., simple hallucination versus complex hallucination) and the level of evidence with which the SOZ could be predicted.

RESULTS

A total of 174 cases comprising 200 AS were analyzed from 70 articles. Across all studies, the SOZ of AS were more often in the left (62%) than in the right (38%) hemisphere. AS heard bilaterally followed this trend. Unilaterally heard AS were more often due to a SOZ in the contralateral hemisphere (74%), although they could also be ipsilateral (26%). The SOZ for AS was not limited to the auditory cortex, nor to the temporal lobe. The areas more frequently involved in the temporal lobe were the superior temporal gyrus (STG) and mesiotemporal structures. Extratemporal locations included parietal, frontal, insular, and rarely occipital structures.

CONCLUSION

Our review highlighted the complexity of AS and their importance in the identification of the SOZ. Due to the limited data and heterogeneous presentation of AS in the literature, the patterns associated with different AS semiologies warrant further research.

Epilepsy With Auditory Features: From Etiology to Treatment

Epilepsy with auditory features (EAF) is a focal epilepsy belonging to the focal epileptic syndromes with onset at variable age according to the new ILAE Classification. It is characterized by seizures with auditory aura or receptive aphasia suggesting a lateral temporal lobe involvement of the epileptic discharge. Etiological factors underlying EAF are largely unknown. In the familial cases with an autosomal dominant pattern of inheritance several genes have been involved, among which the first discovered, LGI1, was thought to be predominant. However, increasing evidence now points to a multifactorial etiology, as familial and sporadic EAF share a virtually identical electro-clinical characterization and only a few have a documented genetic etiology. Patients with EAF usually have an unremarkable neurological examination and a good response to antiseizure medications. However, it must be underscored that total remission might be lower than expected and that treatment withdrawal might lead to relapses. Thus, a proper understanding of this condition is in order for better patient treatment and counseling. Further studies are still required to further characterize the many facets of EAF.

Palinacousis: an eloquent symptom of temporal lobe lesion

A 24-year-old woman was referred to us for an intracranial haemorrhage in the left temporal lobe caused by a ruptured cavernous malformation; the bleeding extended over the left Heschl's gyrus and Wernicke area. On admission, the patient had global aphasia. A few days later, she spontaneously improved but remained with mild residual comprehensive dysphasia. She reported hearing, in her right ear, recently heard words, which is consistent with palinacousis. Auditory acuity testing was normal. EEG showed focal slowing in the left temporal region with no epileptiform activity. During awake surgery for resection of the cavernous malformation, stimulation of the superior temporal gyrus did not provoke palinacousis. The patient made good recovery with complete resolution of the aphasia and no recurrence of palinacousis. We aimed to review this phenomenon and to provide a systematic review of the current literature.

Palinacousis-Auditory Perseveration

Palinacousis is an auditory illusion rarely reported in cases of temporal lobe dysfunction. After reviewing the literature and comparing our clinical experience, we believe that palinacousis can occur as an aura, a simple partial seizure, a complex partial seizure, and/or a postictal event. Palinacousis maybe more common than recognized in patients with receptive aphasias or diffuse cerebral dysfunction, whose language deficits preclude adequate description. We report the case of a 71 years old man with the previously diagnosis of an infarction of left middle cerebral artery and valvular heart disease who presented with the symptoms of palinacousis. He was not diagnosed psychotic diseases. An electroencephalography showed normal wave. He was diagnosed as temporal lobe epilepsy with palinacousis due to post-stroke. Palinacousis was completely reversed after treatment with antiepileptic drug. We report that palinacousis as an epileptic phenomenon can help localized potential lesions and can improve patient care.

Reversible palinacousis from intracranial metastases

Palinacousis is an auditory illusion consisting of perseveration or echoing of an external auditory stimulus after it has ceased. This rare clinical symptom has been reported in ictal (seizure), postictal, and nonictal states, and causative lesions have been most consistently found in or near the temporal lobes. It is distinct from the auditory hallucinations seen in psychiatric illness. We report the case of a 61-year-old man who experienced several days of palinacousis while undergoing treatment for newly diagnosed metastatic lung adenocarcinoma. Palinacousis was presumed to be triggered by intracranial metastases near the auditory cortex. An electroencephalogram showed bilateral theta slowing over the left greater than right temporal lobes without epileptiform activity. Palinacousis remitted with corticosteroid and whole brain radiation therapy.

Palinacousis--evidence to suggest a post-ictal phenomenon

INTRODUCTION

Palinacousis is a paroxysmal auditory illusion in which perseveration of an external auditory stimulus occurs after cessation of the stimulus. The subjects recognize the illusory nature of this experience, which is often a fragment of the last sentence they heard. Palinacousis has been reported in only a few documented cases. It has been described as an aura, a component of complex partial seizures, and a post-ictal event. We put forward evidence demonstrating palinacousis as a post-ictal event.

CASE

A 68-year-old woman presented with an acute sensory aphasia, and an EEG showed frequent epileptiform discharges from the left temporo-parietal region. MRI showed an enhancing mass in the left inferior parietal lobule that was consistent with a metastasis. A CT scan of the thorax later showed an enhancing mass in the left lung that was determined to be an invasive non-small cell carcinoma. Treatment with levetiracetam resulted in loss of epileptiform activity on EEG and resolution of aphasia, but soon afterward, she started complaining of recurrent auditory illusions in her right ear. These consisted of phrases from the ends of sentences she heard. Continuous EEG monitoring during her auditory symptoms showed intermittent left temporal slowing but no epileptiform discharges or electrographic seizures. An FDG-PET scan with the glucose uptake phase during episodes of auditory illusions revealed hypometabolism of bilateral medial temporal cortices and increased uptake in the metastatic tumor.

REVIEW OF LITERATURE

A systematic review identified 14 cases with palinacousis since 1981. Cases prior to that were excluded due to the lack of sufficient data.

DISCUSSION

We propose that palinacousis is a "negative" phenomenon, at least in some individuals. It occurs with a loss of function of a region of the brain that normally suppresses auditory perseveration.

Epilepsy, mental health disorder, or both?

Temporal lobe epilepsy (TLE), a subset of the seizure disorder family, represents a complex neuropsychiatric illness, where the neurological presentation may be complemented by varying severity of affective, behavioral, psychotic, or personality abnormalities, which, in turn, may not only lead to misdiagnosis, but also affect the management. This paper outlines a spectrum of mental health presentations, including psychosis, mood, anxiety, panic, and dissociative states, associated with epilepsy that make the correct diagnosis a challenge.

Misdiagnosis of epileptic seizures as manifestations of psychiatric illnesses

BACKGROUND

Epileptic seizures may be misdiagnosed if they manifest as psychiatric symptoms or seizures occur in patients with known psychiatric illness.

METHODS

We present clinical profiles of six patients with epilepsy (three male, mean age 39 ± 12 years) that presented with prominent psychiatric symptoms.

RESULTS

Two patients had pre-existing psychiatric illnesses. Three patients were initially diagnosed with panic attacks, two with psychosis, and one with schizophrenia. Five patients had temporal lobe epilepsy (TLE) while the sixth patient was subsequently found to have absence status epilepticus (SE). Cranial computed tomogram (CT) including contrast study was unremarkable in five patients and showed post-traumatic changes in one patient. Cranial magnetic resonance imaging (MRI) revealed dysembryoplastic neuroepithelial tumour (DNET) in one patient, cavernous hemangioma in one, and post-traumatic changes plus bilateral mesial temporal sclerosis in another patient but it was normal in two TLE patients. Routine electroencephalography (EEG) revealed absence SE in one patient but it was non-diagnostic in the TLE patients. Video-EEG telemetry in the epilepsy monitoring unit (EMU) was necessary to establish the diagnosis in four TLE patients. None of the patients responded to medications aimed at treating psychiatric symptoms alone. Two patients required surgery while the other four required treatment with anti-epileptic drugs. All the patients had favorable response to the treatment of their epilepsy.

CONCLUSIONS

This case series illustrates that epileptic patients may experience non-convulsive seizures that might be mistaken as primary psychiatric illnesses. In this subset of patients, evaluation by an epileptologist, MRI of the brain, and/or video-EEG telemetry in an EMU was necessary to confirm the diagnosis of epilepsy if routine EEGs and cranial CT are normal.

Palinacousis-Auditory Perseveration: Two Cases and a Review of the Literature

Palinacousis is an auditory illusion rarely reported in cases of temporal lobe dysfunction. Detailed observations where made by Jacobs et al. in 1973. Since that time, only a few other cases have been described in the literature. After reviewing the literature and comparing our clinical experience, we believe that palinacousis can occur as an aura, a simple partial seizure, a complex partial seizure, and/or a postictal event. Within one academic year, we observed two patients who experienced palinacousis. Palinacousis maybe more common than recognized in patients with receptive aphasias or diffuse cerebral dysfunction, whose language deficits preclude adequate description. It is important to differentiate palinacousis from auditory hallucinations seen in psychotic and psychiatric patients. Identification of palinacousis as an aura, simple partial seizure, complex partial seizure, and/or postictal phenomenon can help localize potential lesions and improve patient care.

Lateralizing value of the auditory aura in partial seizures

PURPOSE

To describe the semiological features of auditory aura and to assess their possible lateralizing value in partial epilepsy.

METHODS

Out of a series of 8,000 patients with epilepsy, we investigated 121 cases with partial seizures in whom auditory features were the first ictal symptom. According to the dominant type of aura, patients were divided into four subgroups-1A (67 cases), 1B (22 cases), 2A (14 cases), and 2B (18 cases)-corresponding to the presence of simple or complex hallucinations and positive or negative illusions, respectively. The side of the epileptic zone (EZ) was defined based on available data: surgical/presurgical study or presence of a neuroradiological lesion, corresponding interictal epileptiform EEG and ictal semiology (level 1); a left EZ was also hypothesized in right-handed patients with ictal aphasia plus a left neuroradiological lesion or a left interictal EEG focus (level 2).

RESULTS

Forty-five patients (37%) described the aura as unilateral. The side of epileptogenic zone (EZ) was definable in 36 patients (level 1: 24; level 2: 12). Overall, a unilateral auditory aura was contralateral to the EZ in half of the cases (8/16), but always contralateral in patients studied for presurgical evaluation (4/4). Simple hallucinations lateralized seizure onset on the right side in nine cases, on the left in 12. Among 1B patients (either musical and verbal contents), the EZ was on the left side in all cases (5/5). Positive illusions were associated with right foci in two cases, and left foci in two. Negative illusions always lateralized seizure onset to the dominant hemisphere (6/6).

CONCLUSIONS

Auditory aura is a rare symptom in partial epilepsy. The perception of the auditory sensation referred to one ear is not a unique lateralizing sign for the contralateral temporal neocortex. Complex hallucinations with verbal content and negative illusion may lateralize seizure onset in the dominant hemisphere. The role of laterality for musical hallucinations remains unclear as it depends on individual musical ability and hemispheric dominance for music.