Multisensory hallucinations and other unusual sensory experiences in the context of migraine: a systematic review

OBJECTIVE AND BACKGROUND

Visual auras in migraine have been extensively studied, but less is known about multisensory hallucinations or other unusual sensory experiences, including whether these should be diagnostically considered as part of aura symptoms. The current study aimed to conduct a systematic review and synthesis to bring together existing empirical evidence on these non-visual perceptual experiences, focusing on their phenomenological descriptions and clinical correlates.

METHODS

Forty-eight relevant studies were included based on a systematic search across PsycINFO APA and Web of Science, for peer-reviewed publications in the English language, from 1980 to the present. These comprised a mix of case reports/series (n = 19) and group design studies (n = 29).

RESULTS

Reports of complex multisensory hallucinations, beyond typical established aura symptoms, were numerous and varied in nature. Yet there were limited data on how this related to patient distress and functional interference. Other sensory distortions or hypersensitivities across non-visual domains were also evident, and generally more common in those with established aura symptoms.

CONCLUSION

Our findings provide preliminary evidence that multisensory hallucinations and other unusual perceptual experiences in migraine are likely more common than previously believed. Further investigations are needed to appropriately account for these symptoms within current nosological systems. Increased clinician-patient awareness is important for managing distress (where necessary), and potentially for offering a holistic therapeutic approach to migraine management.

Multisensory Hallucinatory Experiences in Migraine: A Preliminary Basis for Olfactory, Somatic-Tactile, and Gustatory Auras

Background and Objectives

Visual auras in migraine have been extensively studied, but less is known about unusual experiences in other sensory domains, including whether they should be diagnostically considered as part of aura symptoms. This study aimed to examine the prevalence of multisensory aura experiences in migraine and their phenomenologic and clinical correlates.

Methods

Respondents were 729 participants with probable migraine, who completed an online study examining unusual sensory experiences. These comprised aura experiences in the auditory, visual, olfactory, somatic-tactile, and gustatory domains. Basic demographic and clinical information and migraine symptomatology were also collected. To facilitate groupwise comparisons, participants with probable migraine were divided into those with and without (visual) aura experiences.

Results

Endorsement of visual aura experiences was the highest (42.1%), whether in a single modality (44.2%) or multiple (55.8%) modalities, followed by somatic-tactile (32.0%), gustatory (21.9%), olfactory (18.6%), and auditory (11.0%) domains. Phenomenologic similarities, for instance, in frequency, personification, and controllability, existed across sensory domains. Somatic-tactile and gustatory auras conversely exhibited greater duration and negative emotional valence. Participants with probable migraine with visual aura tended to report significantly more severe migraine symptoms relative to those with nonvisual or no aura.

Discussion

Our findings provide preliminary indication that unusual olfactory, somatic-tactile, and gustatory experiences in migraine are common and could be clinically significant as aura symptoms. Increased clinician and patient awareness and effective management of these symptoms are essential for a holistic therapeutic approach to migraine.

Exploring the associations between auditory hallucinations and psychopathological experiences in 10,933 patient narratives: moving beyond diagnostic categories and surveys

BACKGROUND

Previous research suggests that auditory hallucinations are prevalent within both the clinical and general populations. Yet, we know little about how these phenomena are associated with other psychopathology symptoms and experiences. The current study aids investigations towards preventing, predicting and more effectively responding to such distressing occurrences. There have been substantial efforts in the literature to propose models of auditory hallucination and attempts to verify them. However, many of these studies used survey methods that restrict the person's responses to a set of pre-defined criteria or experiences and do not allow exploration of potential important other symptoms beyond them. This is the first study to explore the correlates of auditory hallucination using a qualitative dataset consisting of unrestricted responses of patients about their lived experiences with mental illness.

METHOD

The study used a dataset consisting of 10,933 narratives from patients diagnosed with mental illnesses. For analysis, the study used correlation on the text-based data. This approach is an alternative to the knowledge-based approach where experts manually read the narratives and infer the rules and relationships from the dataset.

RESULT

This study found at least 8 correlates of auditory hallucination (small correlation coefficients), with the unusual ones being "pain." The study also found that auditory hallucinations were independent of obsessive thoughts and compulsive behaviours, and dissociation, in contrast with the literature.

CONCLUSION

This study presents an innovative approach to explore the possible associations between symptoms without the restrictions of (or outside the confines of) traditional diagnostic categories. The study exemplified this by finding the correlates of auditory hallucination. However, any other symptom or experience of interest can be studied similarly. Potential future directions of these findings are discussed in the context of mental healthcare screening and treatment.

Aura Mapping: Where Vision and Somatosensation Meet

While migraine auras are most frequently visual, somatosensory auras are also relatively common. Both are characterized by the spread of activation across a cortical region containing a spatial mapping of the sensory (retinal or skin) surface. When both aura types occur within a single migraine episode, they may offer an insight into the neural mechanism which underlies them. Could they both be initiated by a single neural event, or do the timing and laterality relationships between them demand multiple triggers? The observations reported here were carried out 25 years ago by a group of six individuals with migraine with aura. They timed, described and mapped their visual and somatosensory auras as they were in progress. Twenty-nine episode reports are summarized here. The temporal relationship between the onset of the two auras was quite variable within and across participants. Various forms of the cortical spreading depression hypothesis of migraine aura are evaluated in terms of whether they can account for the timing, pattern of symptom spread and laterality of the recorded auras.

Can you have a migraine aura without knowing it?

PURPOSE OF REVIEW

This review covers several aspects our understanding of episodic manifestations and unusual symptoms that may be associated with migraine aura.

RECENT FINDINGS

The episodic manifestation of migraine aura is typically visual in nature, although five other types are currently recognized: sensory, speech and/or language, motor, brainstem, and retinal. Other transitory perceptions or experiences such as emotional, olfactory, or auditory have been reported as possible migraine auras. As underlined by the much higher reported prevalence of aura manifestation in individuals with professional knowledge of its possible manifestations, it appears that a number of migraine auras may remain unnoticed, unreported, or misdiagnosed.

SUMMARY

Aura manifestations may be more common, complex, symptom-rich and variable than previously thought. Clinicians should proactively ask questions beyond those addressing visual symptoms when examining individuals with a potential diagnosis of migraine with aura.

Did René Descartes Have Exploding Head Syndrome?

ABSTRACT

René Descartes (1596-1650), "the Father of Modern Philosophy" and advocate of mind-body dualism, had three successive dreams on November 10, 1619 that changed the trajectory of his life and the trajectory of human thought. Descartes' influential dreams have been of interest to a number of commentators including the famous neurologist and psychoanalyst Sigmund Freud. Descartes' second dream in particular, in which he heard a loud noise in his head before seeing a bright flash of light upon awakening, has been discussed extensively. Commentators have employed psychoanalytic and medical explanations to account for Descartes' unusual nocturnal experience. In this tradition, I propose that Descartes' second dream was not a dream at all; rather, it was an episode of exploding head syndrome; a benign and relatively common parasomnia. I further suggest that Adrien Baillet's account of Descartes' experience constitutes the earliest description of exploding head syndrome, predating the account described by Silas Weir Mitchell in 1876 by nearly 200 years.

Clinical description of attack-related cognitive symptoms in migraine: A systematic review

Introduction

Cognitive symptoms have been described during migraine attacks since the Roman era; while being neglected throughout the centuries, they are relevant contributors to migraine-related disability.

Objective

To determine whether cognitive symptoms are included in clinical series describing migraine attack phenomenology, and which symptoms occur in each attack phase.

Method

Systematic review of existing data on clinical descriptions of migraine attacks, focusing on cognitive symptomatology. Data were organized and analyzed qualitatively, due to methodological differences between studies.

Results

Twenty-four articles were reviewed, with a total sample of 7007 patients, including 82.9% females with an average age of 39.2 years. Twenty one (75%) studies analyzed one phase of the attack (eight prodromes, five auras, one between aura and pain, three headaches and three postdromes), the remaining studied more than one phase. Cognitive complaints were the most frequent symptom of the prodromic (30%) and headache (38%) phases, while fatigue (70%) dominated the resolution phase. Not enough data is available to estimate the frequency of cognitive symptoms during the aura.

Discussion

Cognitive symptoms are described in all phases of the migraine attack phenomenology in published clinical series of migraine. Their characteristics appear to be different in each attack phase, although methodological limitations prevent generalization of this finding.

Multisensory Integration in Migraine: Recent Developments

There are well-documented unimodal sensory differences in migraine compared to control groups both during, and between migraine attacks. There is also some evidence of multisensory integration differences in migraine groups compared to control groups, however the literature on this topic is more limited. There are interesting avenues in the area of visual–vestibular integration, which might have practical implications, e.g., motion sickness and nausea in migraine. Recent work has been investigating the possibility of visual–auditory integration in migraine, and found possible differences in the susceptibility to the sound-induced flash illusion in particular, which could give insights into relative excitability of different areas of the cortex, and also into mechanisms for the illusions themselves. This review updates the most recent literature and also highlights potentially fruitful areas of research to understand one of the most common neurological disorders.