Table 2.

Multisensory hallucinatory and other unusual sensory experience in migraine (n = 29 empirical studies)

References	N, participant characteristics, age (M ± SD in yrs) and sex (% male)	Established aura symptoms (including visual; complex visual hallucinations presented in next column)	*Description of complex hallucinatory experiences (visual, auditory, olfactory, tactile, gustatory and other lesser-known modalities)	Unusual sensory experiences (prodromal or postdromal symptoms)	*Unusual sensory experiences (other)
Albanese et al. [41]	Mi+: n = 50, 36 ± 10, 30% HC: n = 58; 35 ± 8, 34%	n = 15 MA +; n = 35 MA− MA + had VA only	N/A	N/A	22% Mi + had ear fullness
Alstadhaug et al. [42]	n = 245; 55 ± 13, 62%; MA+: n = 95, 62%	98% of MA + had VA; ~ 8% of MA + had sensory auras; 14% of n = 245 had VA without headache; n = 10 had migrainous vertigo at least once	N/A	N/A	8% of n = 254 had UA + including distorted perception of time (n = 3), out-of-body sensation (n = 2), deja vu (n = 1), jamais vu (n = 1), microsomatognosia (n = 1)
Ashkenazi et al. [43]	n = 38; MA + n = 12; MA − n = 26, median = 26 (range 18–51); 21%	N/A	N/A	90% of AL + & 75% AL- had phonophobia; 97% AL + and 88% of AL- had photophobia; 53% of AL + rated phonophobia during Mi as moderately worse than phonophobia between Mi; 75% of AL- rated phonophobia during Mi minimally worse than phonophobia between Mi	35% of AL + and 25% of AL- had osmophobia during attacks
Baldacci et al. [17]	n = 100 Mi +; 39 ± 11; 33%	N/A	N/A	N/A	58% of n = 100 had osmophobia
Beh et al. [11]	n = 17 Mi +; Median = 49 (range = 17–63); 41%	47% had MA + (visual distortion): illusory splitting, teleopsia ("furniture seems far away, floor fells like a canyon"), underwater vision, xanthopsia ("yellow tint washing into visual field like a tide"), visual dolly zoom effect, frosted glass vision, enhanced stereoscopic vision ("seeing everything in extreme detail or extra 3D vision"), closed-eye visual hallucinations ("flashing images of unfamiliar people, trees, mountains, or buildings and phosphenes when eyes closed"). ~ 50% had visual distortion occurring during vestibular Mi, lasting for duration of Mi episodes (1–3 days); the distortion occurring between attacks usually lasted for mins to hours	100% Alice in Wonderland syndrome. Auditory distortion (“unable to hear own voice”) occurred during and lasted whole duration of Mi episodes (2–4 h). 41% had extrapersonal misperceptions: derealisation or out-of-body experience; most extrapersonal misperceptions occurred during and lasted whole duration of Mi. 29% had somesthetic distortion: aschematia “feeling as though [they] have no eyes but knows [they are] able to see”; partial macrosomatognosia – “brain becoming too big”; total body macrosomatognosia – “feels like [they are] growing so big [their] head would push through the roof”; microsomatognosia – “feels [they are] shrinking and becoming so small [they] would disappear behind the steering wheel”; most somesthetic symptoms occur during and lasted whole duration of Mi, except total body macrosomatognosia and microsomatognosia for n = 1 occurred between Mi episodes. 6% of Mi + experienced time distortion: "everything suddenly slowing down and moving very slowly even if [they were] driving at 80 mph on a highway"; occurred 1 day after Mi and lasted 5 min
		MA + found these experiences more fascinating than worrisome
Celebisoy et al. [44]	Vestibular M: n = 415, 42 ± 12 (17–74), 15%	10% of N reported hearing loss in audiometry; 41% of N reported tinnitus; 69% of N reported vertigo attacks lasting 60 min–24 h; 62% of N reported vertigo attacks associated with headache in > 50% of the attacks; median vertigo attack severity = 7a	N/A	42% of N reported photophobia or phonophobia	32% of N reported aural fullness; 20% of N reported osmophobia; 12% of N reported AL
Demarquay et al. [45]	n = 74 Mi + (n = 48 non-olfactory hypersensitive (OH-), n = 26 olfactory hypersensitive (OH +)), n = 30 HC; Mi + 42 ± 12; OH- 41 ± 13, OH + 44 ± 10, HC: 38 ± 12; Mi + 18%, OH- 15%, OH + 23%, HC 27%	23% of OH- had non-olfactory established aura; 15% of OH + had non-olfactory established aura	N/A	N/A	35% of Mi + had interictal olfactory hypersensitivity. OH + judged odours as less pleasant than OH- (p = 0.002) and controls (p = 0.006)
Dispenza et al. [19]	n = 30 Mi + with vertigo; 45 (range 18–64 yrs), 20%	n = 12 VA; all had vertigo; n = 10 had episodic tinnitus	N/A	n = 20 patients reported dizziness and unsteadiness. All had photophobia, n = 26 patients reported phonophobia	n = 20 had transitory ear fullness sensation, of which n = 9 had both symptoms after first pure tone audiometry testing
Gossrau et al. [46]	Mi: n = 113, 46 ± 14, 12%	44% of N reported Mi with aura	N/A	N/A	38%, 62% and 32% of n = 113 reported preictal, ictal and interictal hypersensitivity to odours respectively; common feared odours: perfumes, food odours and smoke (~ 35%, 22% and 12% of Mi + with osmophobia respectively)
Hansen et al. [47]	n = 267; MA +, 39 ± 11; 20%	Most common auras were dots or flashing lights (70%), wavy or jagged lines (47%), blind spots (42%) and tunnel vision (27%)	Visual hallucinations (n = 22). 19% of MA + experienced changes in smell	88% of Mi attacks were associated with photophobia and 73% with phonophobia	14% of MA + had changes in taste or touch
		Blurry vision (n = 22), photopsia (n = 14), halos (n = 7), obscuration (n = 4) and micropsia (n = 1). Most reported > one VA symptom (median = 2, range 1–5). 30% had numbness or pins and tingling
Jürgens et al. [14]	n = 149 MA −, n = 70 MA +; n = 161 HC; MA− = 40; MA +  = 39; HC = 42; MA− = 15%; MA +  = 11%; HC = 20%	91% MA + reported VA symptoms. visual illusions: autokinesis, corona phenomenon, cinematographic vision, double vision, macropsia, micropsia, pelopsia, teleopsia, metamorphopsia, visual splitting, inverted vision, inversion of 2D/3D vision, dyschromatopsia and illusionary visual spread. 23% MA + had sensory aura symptoms	5% Mi + had complex visual hallucination. Mi + reported distorted perception: altered perception of body size, altered perception of body weight, altered perception of body position in space. Others: out-of-body experience, doppelganger phenomenon, synesthesia	N/A	N/A
Kandemir et al. [48]	MA+: n = 30, 34 ± 8, 13%; MA−: n = 30, 32 ± 8, 27%; HC: n = 30, 32 ± 7, 20%	N/A	N/A	N/A	77% MA + and 60% MA − reported osmophobia; perfume and cleaning products were the most common offensive odours during or between Mi attacks
Karli et al. [15]	n = 96 (n = 23 MA +, n = 33 MA −, n = 31 episodic tension-type headache (ETTH); n = 9 Aura without headache (A + H-)); MA +  = 40 ± 11, MA− = 37 ± 10, ETTH = 35 ± 10, A + H− = 35 ± 10; MA +  = 9%, MA− = 3%, ETTH = 23%, A + H− = 0%	44% of MA + had photopsia as VA; 33% of MA − also experienced photopsia before or during headache, but the symptom lasted < 5 min. 47% of MA + had fortification spectra. 39% of MA + had scotoma. 48% of MA + had paraesthesia, 12% MA − had paraesthesia within 1 h before or during headache, but the symptom lasted < 5 min	22% of MA + had olfactory hallucinations, 6% of MA − had olfactory hallucinations	Photophobia before headaches: 91% of MA +, 85% of MA −. Phonophobia before headaches: 87% of MA +, 91% MA −	13% of MA + had micropsia/macropsia; ↑ % of MA + felt cold before headache than MA −
Kayabaşoglu et al. [18]	n = 30 HC, n = 60 Mi +; HC range = 20–56 yrs, Mi + range = 20–54 yrs; HC = 40%; Mi +  = 39%	N/A	N/A	N/A	Mi + detected odorant at ↓ odour concentration level than HC (threshold scores: 8 ± 2 Mi + with osmophobia; 8 ± 2 Mi + without osmophobia; 11 ± 1 HC, p < 0.001). Mi + with osmophobia had ↑difficulty discriminating odours. (discrimination scores: 6 + 1 Mi + with osmophobia; 9 + 1 Mi + without osmophobia; 12 ± 1 HC, p < 0.001). Mi + with osmophobia rated perfume (80%), smoke (70%), stale food (63%), fish (47%), coffee or spices (40%) and leather (40%) as a disturbing smell
Kelman [49]	n = 952 Mi +; 38 ± 12; 15%	92% of MA + had VA. VA was often the only aura symptom. 67% of MA + rated VA as very frequent. Out of total episodes of sensory aura (numbness and tingling), only 9% of sensory aura occurred in absence of VA. Those w/more frequent VAs were ↑likely to experience more frequent non-VA symptoms. 26% of MA + had frequent numbness or tingling sensation. n = 1 participant had hearing loss. n = 2 had tinnitus	N/A	When asked about “other aura symptoms before Mi”: n = 4 had photophobia	When asked about “other aura symptoms before Mi”: n = 1 patient reported vision jumping, “things go black. n = 1 had smell intolerance, strange smells. n = 1 had strange taste, metallic taste and acid taste. n = 1 had facial pain, flushing of face, chest tightness, body cold, neck tightness, head tightness, neck burning, stiff neck and shoulder burning
Leveque et al. [50]	MA−: n = 46, 29 ± 9, 22%; HC: n = 46, 27 ± 11, 28%	N/A	N/A	Mi + experienced ↑ sensory hypersensitivity than HC in the visual (p < 0.001) and auditory modalities (p = 0.002); visual hypersensitivity correlated with auditory in Mi + in interictal periods (r = 0.3, p = 0.0043) and ictal period (r = 0.432, p = 0.003)	Mi + experienced ↑ sensory hypersensitivity than HC in olfactory modality (p = 0.032); olfactory hypersensitivity correlated with auditory hypersensitivity (r = 0.315, p = 0.033) in ictal period
Mahmud and Sina [51]	MA+: n = 18; 30 (24–36), 17%; Patient with occipital epilepsy: n = 10, 22 (15–47), 20% age presented as median and IQR	Scotomas, white or golden dots, or light flashes lasting for minutes before the headache; median duration of the visual phenomenon = 460 s, IQR: 225–1800; vertigo (56% MA +) and tinnitus (6% MA +)		Photophobia (94% MA +), phonophobia (89% MA +)	Osmophobia (39% MA +); 2 MA + reported transient loss of consciousness as aura symptoms
Mainardi et al. [4]	Mi + with olfactory hallucinations: n = 11 (10MA −, 1MA +), 40 (25–36), 18%	N/A	Reported olfactory hallucinations included smell of burnt wood, vanilla, gas, jasmine, coffee, smoke, rotten meat, banana, bitter almonds, chemical, melon, metallic, sulphur. The smells were always the same for most participant. Average age of onset of olfactory hallucinations = 32 yrs (5–54); ~ 50% of n = 11 had sudden onset and stop of olfactory hallucinations; ~ 70% of n = 11 reported olfactory hallucinations lasted 3–10 min; all Mi + reported changing intensity of olfactory hallucinations during the attack (mild or extremely intense); ~ 70% of n = 11 considered the smell consistently unlikeable	Phonophobia and photophobia constantly accompanied the pain phase in all patients	50% of n = 11 reported osmophobia
Pekdemir and Tanik [52]	n = 145; Mi with osmophobia: n = 98, 36 ± 11, 14%; Mi with osmophobia: n = 47, 36 ± 9.26%	N/A	N/A	N/A	68% of Mi + reported osmophobia; median scores of ASC-12 (allodynia symptom checklist): Mi + with osmophobia = 5 (mild AL) and Mi + without osmophobia = 2 (no AL)
Petrusic et al. [53]	MA+: n = 40, 16 ± 2 (13–19), 50%	38% of MA + had VA only; 20% of MA + had visual and somatosensory auras; common VA included scintillating scotoma (67.5% of MA +), blurry vision (60%), tunnel vision (40%) and zigzag lines (25%); Feature of scintillating scotoma: onset time 21 ± 16 (25–60) mins in regard to the beginning of headache; duration 19 ± 17 (2–75) mins; 60% of MA + had somatosensory symptoms, including numbness in the left hand or both hands (53% of MA +), numbness in lips and/or face (30%), tongue (28%) and legs (15%)	N/A	N/A	23% MA + experienced deja vu phenomenon during the aura; 5% of MA + experienced neglecting hand syndrome (duration: 1 ± 18 (5–30) mins)
Price et al. [54]	Mi + with probable Mi: n = 117, 48 ± 14, 15%; HC: n = 827, 54 ± 17, 35%	N/A	N/A	Mi + have a ↑ level of sensory sensitivity in visual and auditory modalities than HC (p < 0.001)	Mi + have a ↑ level of sensory sensitivity in touch and taste modalities than HC (p < 0.001); sensory sensitivities in the different sensory modalities (visual, touch, taste and auditory) are correlated with each other (p < 0.01)
Saisu et al. [16]	n = 110, MA+: n = 31, 34 ± 10, 29%; MA−: n = 49, 35 ± 11, 23%; HC: n = 30, 35 ± 11.25%	N/A	No differences in gustatory sensation (hypogeusia or hypergeusia) found between Mi + and HC or between the MA + and MA −	66% Mi + reported photophobia and 74% Mi + reported phonophobia; ↑ MA + had photophobia and phonophobia than MA − (p < 0.05)	63% Mi + reported osmophobia: 45% MA + and 29% MA − found perfume offensive; 29% MA + and 5% MA − found cigarette smoke offensive; ~ 50% Mi + with osmophobia experienced osmophobia since the initial onset of Mi, before Mi attacks or within 30 min after attack onset; 71% Mi + with osmophobia had osmophobia stopped when the Mi ended; Mi + showed ↑ dislike towards odours of Japanese cypress, rose and perfume than HC (p < 0.05); MA + showed ↑ dislike towards clothes smelling of perspiration, rose scents and odours of cooking gas and curry than MA − (p < 0.05); 10% Mi + had dysgeusia
Shepherd and Patterson [5]	n = 151, MA+: n = 33, 39 ± 12, 27%; MA−: n = 44, 36 ± 11, 23%; HC: n = 74, 32 ± 8, 59%	3 MA + experienced tinnitus (buzzing in the ears); n = 9 MA + experienced dizziness or vertigo; 32 MA + experienced VA (included wavy lines, zigzags, squiggles, radiating lines, a sparkly big wheel, black and silver lines, flashes of dots, a scintillating scotoma, moving bright blue and black swirls like a lava lamp); most VA included motion, started small and centrally and then grow out to the periphery, superimposed on objects, obscuring them; 12 MA + experienced pins and needles or numbness, most commonly on one side of the face or on the nose, lips and mouth, less frequently on a hand or the fingertips, down one arm, leg or foot; Higher proportion of MA + experienced distorted or non-shared sensory experiences in visual modality (e.g. see shapes, lights, or colours when there is nothing there) than MA − and lastly than HC	↑ proportion of MA + experienced distorted or non-shared sensory experiences in auditory modality (e.g. hear noise and sounds that people near you do not; find sounds are distorted in a strange way), in olfactory modality (e.g. detect smells which do not seem to come from your surroundings), in tactile modality (feel someone is touching you but when you look nobody is there; burning sensation on your body), in gustatory modality (e.g. food or drink seems to have an unusual taste; unexplained tastes in your mouth) than MA − and lastly than HC	↑ proportion of MA + experienced visual and auditory sensitivity than MA − and lastly than HC	2 MA + experienced double vision; ↑ proportion of MA + experienced olfactory and tactile sensitivity (e.g. notice skin is more sensitive to touch, heat or cold than usual) than MA − and lastly HC
Shi et al. [55]	Vestibular Mi: n = 166, 43 ± 15 (6–76), 21%	52% of N had tinnitus; 21% of N had hearing loss- majority had mild and easily reversible low-frequency hearing loss; ↑ Mi + with hearing loss experience tinnitus versus those without (tinnitus = 80% of Mi + with hearing loss vs. 44% of Mi + without hearing loss); 14% of N had visual aura; most Mi + reported vestibular symptoms (incl. vertigo, dizziness and lightheadedness) monthly or yearly and lasted 5 min–72 h	N/A	32% of N had phonophobia; 24% of N had photophobia	8% of N had otalgia (majority one sided); 41% of N had aural fullness (majority one sided); ↑ Mi + with hearing loss experience aural fullness than those without (p < 0. 05) (aura fullness: 89% of Mi + with hearing loss vs. 29% of Mi + without hearing loss)
Silva et al. [12]	Sightless Mi+: n = 8, 40 ± 13 yrs (range 25–56), 33%	Short VA (< 5 min), with colour blue, silver or fire like and usually in round shapes,	Uncharacteristic noise	Photophobia reported by all Mi + whom the headache preceded the blindness in time (n = 6) disappeared after visual impairment	N/A
Sjaastad et al. [13]	n = 1838, mean = 43, 49%	10% of n = 1838 had visual disturbances: scintillating scotoma (62% of N with visual disturbances), obscuration (33%), photopsia (unformed flashes of light/star-shaped figures) (16%); photopsia coexisted with scintillating scotomas and/or obscuration occasionally; anopsia (dimness of vision) (5%), autokinesis (movement of stationary objects), tunnel vision and micropsia (< 5%); most of the rare visual disturbances (< 5% of N with visual disturbances) appeared before pain and appeared with other visual disturbances at the same time; 67% of those with visual experienced reported the experience lasted from > 15 to ≤ 35 min	One participant had red and hot ears bilaterally during Mi	N/A	N/A
		Paraesthesias usually occurred at face or upper extremity and occurred at multiple locations during Mi
Teggi et al. [56]	Definite vestibular Mi+: n = 252, 46 ± 14 (range = 19–76), 15%	11% Mi + had tinnitus; 73% Mi + had internal vertigo – a false sensation of self-motion when no self-motion is occurring; ~ 50% Mi + with internal vertigo had spinning sensation; the age at the first vertigo attack = 38 ± 13 yrs (range 16–60 yrs.); vertigo usually lasted < 5 min (23% Mi +) or 6–60 min (22% Mi +)	N/A	Photophobia (44% Mi +), phonophobia (39% Mi +)	Fullness of the ear (9% Mi +)
Wang et al. [6]	MA−: n = 52, 24 ± 10; MA+: n = 28, 24 ± 10.00 (F), 19 ± 2 (M), 50%	MA + were ↑ likely to experience vision blurred and seeing black spot during Mi versus MA − (p < 0.01);	MA + were ↑ likely to experience the sensations that "head being hooped by a ribbon", "head being pressed by a big stone", "feeling like I was wearing hat" during Mi versus MA − (p = 0.01)	Blurred vision, light hypersensitivity (sensitivity to strong light when headache attacked), sound hypersensitivity	N/A
Zanchin et al. [57]	n = 1005, 37 ± 11, 23% MA−: n = 677, 38 ± 11, 20% MA+: n = 130, 36 ± 11, 27% Tension-type headache: n = 198, 36 ± 12, 31%	N/A	N/A	N/A	44% MA − and 39% MA + had osmophobia during Mi; For Mi + with osmophobia: 91% had osmophobia since first headache; 53% had osmophobia in 10/10 attacks; 73% had osmophobia during Mi; 98% had osmophobia stop with the pain phase; 43% had sensitivity towards two types of odours; most frequently reported offending odours: scents (e.g. feminine scents, deodorants, fresh flowers) (64% Mi +), food (e.g. coffee, fried foods, onion, etc.) (55% Mi +) and cigarette smoke (55% Mi +)

n = Number of participants; M ± SD = Mean ± standard deviation; HC = Healthy Controls; IQR = Interquartile Range; mins = Minutes; Mi = Migraine; Mi +  = People with migraine; MA +  = Migraine with aura; MA− = Migraine without aura; UA +  = Unusual aura; VA = visual aura; yrs = years

^aMeasured on a 0–10-point scale. Ear fullness is currently noted as established symptoms for other headache disorders, but not migraine with or without aura, in the ICD-3, and therefore was included as an “Unusual sensory experience (other)” for the purposes of the present study. Group specific information is reported if presented in this study