Palinacousis: an eloquent symptom of temporal lobe lesion
- Catherine Veilleux ,
- Gilles El-Hage ,
- Nathalie L'Ecuyer and
- Michel W Bojanowski
- Division of Neurosurgery, University of Montreal, Montreal, Quebec, Canada
- Correspondence to Professor Michel W Bojanowski, Division of Neurosurgery, University of Montreal, Montreal, Quebec, Canada; michel.bojanowski.chum@ssss.gouv.qc.ca
Abstract
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.
Background
Palinacousis was first described in 1971 by Jacobs et al 1 as a perseveration or recurrence of recent auditory sensations after the stimulus has ceased. This phenomenon was first observed intraoperatively during temporal lobe stimulation by Wilder Penfield,2 which he reported in 1963, but the term ‘palinacousis’ was later coined by Jacobs et al.1 Such episodes of hearing usually last from seconds to hours.3 Hence, unlike auditory phenomena in many psychiatric conditions, the sounds perceived in palinacousis are not persecutory delusions. In palinacousis, the auditory sensations may include spoken language, vocal sounds, musical sounds as well as environmental sounds.4–6 Although it has been hypothesised that palinacousis may be caused by seizures, its pathophysiology is still poorly understood.3
We report the case of a patient who experienced palinacousis following a brain haemorrhage in the Heschl’s gyrus and in the Wernicke area due to a ruptured cavernous malformation (CM). Paraclinical evaluation did not reveal evidence of seizure activity. Likewise, intraoperative cortical stimulation did not induce palinacousis.
Our goal in reporting a case of palinacousis and systematically reviewing the literature regarding this rare condition is to highlight the fact that palinacousis is almost always associated with a recognisable structural brain lesion and that care must be taken so as to not confuse it with other forms of auditory hallucinations. We will also discuss possible mechanisms involved in its pathophysiology.
Case presentation
A 24-year-old Caucasian right-handed woman was transferred to our hospital for global aphasia of unknown aetiology. She had no neurological or psychiatric history and had completed undergraduate studies. MRI revealed left-sided subarachnoid haemorrhage and intraparenchymal haemorrhage in the left temporal lobe, involving the Heschl’s gyrus and the Wernicke area, secondary to a ruptured CM. Significant oedema of the surrounding brain tissue was also present (figure 1). Three days later, as her aphasic symptoms greatly diminished, the patient reported hearing previous recently heard words and sounds in her right ear. Most of the time, she heard only one word, although she reported hearing paraphrases at times. She reported these spontaneous repetitions of past sounds to be more frequent before bedtime or during a conversation. The maximal delay between the stimulus and the echo was 1 hour, and she usually heard the echo immediately following cessation of the stimulus. These auditory hallucinations were vivid and she was fully aware of them. The episodes lasted from 30 s to 5 min. She described the sound as a neutral voice, which might have been her own, and was uncertain whether she would be able to determine the gender of the voice. Although she was unable to stop the reoccurrence of these echoes, she was still capable of focusing her attention on the current conversations she was having with her left ear. However, it did at times disrupt the conversation, as she was under the impression people were conversing using the same words over and over again, making it difficult to follow. She did not have any other symptoms including emotional disturbance or signs of psychiatric illness. She did, however, present residual deficits in word association, word recognition and word-finding at the time of her palinacousis. Palinacousis disappeared spontaneously within approximately 48 hours of its emergence.
T2 Fast Fluid Attenuated Inversion Recovery (FLAIR) Coronal and Axial MRI demonstrating the cavernous malformation extending over the left gyrus of Heschl.
Investigations
Head MRI revealed a left temporal parenchymal haematoma with oedema extending over the Heschl’s gyrus and Wernicke area due to the rupture of a CM (figure 1). An adjacent venous developmental anomaly draining into the left lateral ventricle was also noted. These findings were consistent with the underlying ruptured cavernoma.
Speech assessment was done 48 hours after her admission and revealed mild to moderate receptive aphasia with impaired oral and written comprehension as well as impaired verbal memory. A mild difficulty pronouncing and repeating words was also noted. Speech was fluent, with adequate content using complex sentences.
An electroencephalogram (EEG) was conducted a few days after the symptoms had ceased and showed focal slowing in the left temporal region with no epileptiform abnormalities. Auditory acuity testing was within normal limits.
Treatment
In order to avoid a rebleeding of the CM, surgical resection was proposed. Nine days following admission, awake brain surgery was undertaken. To prevent seizure during the surgery, a bolus of phenytoin was administered prior to surgery. During the surgery, cortical stimulation of the superior temporal gyrus was performed, and the stimulations did not reproduce any palinacousis. The haematoma was suctioned out, followed by resection of the cavernoma while preserving the associated venous developmental anomaly (video 1). The surgery was uneventful.
Outcome and follow-up
Postoperatively, the patient had no new neurological deficit. She was discharged 4 days following surgery and levetiracetam was prescribed prophylactically for a period of 2 months given that there had been a ruptured symptomatic CM for which the patient had undergone surgery and that palinacousis may have been a seizure phenomenon. Two months later, when the patient was seen in the outpatient clinic, neurological examination was normal and there was no recurrence of the palinacousis. MRI revealed no residual CM (figure 2). The patient was seen again 6 months following surgery and was symptom-free.
T2 Fast Fluid Attenuated Inversion (FLAIR) Coronal and Axial MRI demonstrating postoperative status and complete resection of the cavernous malformation.
Discussion
Palinacousis is an auditory perception of previously heard sounds occurring after the corresponding external auditory stimulus has ceased. It is distinct from the types of auditory hallucinations experienced in psychiatric disorders such as schizophrenia or mood disorders, as there are no paranoid thoughts nor are the sounds emotionally upsetting. Furthermore, there are no other neurotic or psychotic symptoms nor history thereof in palinacousis. Palinacousis is further triggered by an auditory stimulus, whereas auditory hallucinations in psychotic illnesses are not. These differences are important in order to avoid misdiagnosing palinacousis as a mental illness.3 In palinacousis, the patient is fully aware that the sound is an echo of a previously heard sound, and there is no irrational affective response. Pseudo-hallucinations also present with preserved insight in the absence of psychotic symptoms, as in our patient’s case; however, they are typically described as ‘not as vivid’ as true hallucinations, which was not the case in our patient.7 Furthermore, pseudo-hallucinations often involve more than one sensory modality and have a ‘naïve, fantastic or childish content’, which again was not the case in our patient.8
We conducted a systematic review following the guidelines of the Preferred Reporting Items for Systematic Review and Meta-Analysis Protocols. A PubMed search of the word ‘palinacousis’ yielded 26 reports, including 3 review articles. All articles were cross-referenced to look for other case reports or case series of palinacousis in human subjects. All publications were considered and there were no exclusions based on year of publication or primary language of the article. Articles were excluded if the reported case did not describe perseveration of previously heard sounds or words. We also excluded all review articles of palinacousis (online supplemental figure E1).3 4 6 9 Consequently, we retained in our systematic review 22 articles for a total of 35 cases,1 4 6–25 to which we added our own case for a total of 36 cases in this study. A detailed description and flow chart of all identified cases can be found in online supplemental table E1 and figure E1.
Supplementary data
Supplementary data
Palinacousis may occur at any age; in the cases described, ages ranged between 15 and 78 years. Men and women also appear to be equally affected (table 1). In cases where handedness was reported, there were no left-handed patients, while 10 were right-handed,11 13 14 17 23 24 26 27 including our patient (table 2). Most patients heard the perseverating sound immediately after cessation of the original auditory stimulus.1 10 11 14 15 17 18 23 27 Some cases report patients heard their own voice as an echo.5 10 13 14 17 21 28 Some patients also reported perseveration of their inner speech,10 14 22 which has been termed palinendophonia by a group of authors.14 In cases where speech deficits or absence thereof was reported, six patients had no speech deficits,10 13 22 23 six had receptive aphasia,11 15–17 19 including our case, one was globally aphasic,17 28 while one had non-specific speech abnormalities.16 Palinopsia, which is defined as perseveration or recurrence of a visual image after the stimulus has ceased, was also described concurrently with palinacousis in four cases.6 24 25
Demographic characteristics
Demographic characteristics
Clinical presentation characteristics
| Subject group | Cases, n (frequency %) |
|---|---|
| Lesion aetiology | |
| Tumour (glioblastoma, meningioma, metastases, schwannoma unspecified brain tumour) | 8 (22.2) |
| Vascular malformation | 4 (11.1) |
| Intraparenchymal haemorrhage | 4 (11.1) |
| Postoperative changes | 2 (5.6) |
| Others (polymicrogyria, temporal epilepsy, infarction, Wernicke encephalopathy, hypoperfusion, necrosis, etc) | 9 (22.2) |
| Non-lesional | 5 (13.9) |
| Non-specified | 5 (13.9) |
| Handedness | |
| Right-handed | 10 (27.8) |
| Left-handed | 0 (0) |
| Ambidextrous | 1 (2.8) |
| Non-specified | 25 (69.4) |
| Lesion lateralisation | |
| Right hemisphere | 14 (38.9) |
| Left hemisphere | 14 (38.9) |
| Bilateral | 3 (8.3) |
| Others (ie, alcohol cessation, antipsychotic cessation) | 5 (13.9) |
| Lobe localisation | |
| Temporal | 14 (38.9) |
| Frontotemporal | 4 (11.1) |
| Temporo-occipital | 4 (11.1) |
| Parietal | 3 (8.3) |
| Temporoparietal | 3 (8.3) |
| Others (ie, inferior colliculi, medial geniculate nucleus) | 3 (8.3) |
| Non-applicable (ie, alcohol cessation, antipsychotic cessation) | 5 (13.9) |
Footnotes
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Contributors CV: took the lead in writing the manuscript, conducted review of current literature, prepared figures 1 and 2, conducted the interview for patient’s perspective. GE-H: contributed to video preparation, assumed critical revision of the manuscript for intellectual content. NL’E: contributed to conducting the interview for patient's perspective, assumed critical revision of the manuscript for intellectual content, gathered patient’s data for case report. MWB: original idea, assumed critical revision of the manuscript for intellectual content, lead neurosurgeon on the case.
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Funding The authors have not declared a specific grant for this research from any funding agency in the public, commercial or not-for-profit sectors.
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Competing interests None declared.
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Provenance and peer review Not commissioned; externally peer reviewed.
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