TY - JOUR
T1 - Functional MRI study in a case of Charles Bonnet syndrome related to LHON
AU - Vacchiano, V.
AU - Tonon, C.
AU - Mitolo, M.
AU - Evangelisti, S.
AU - Carbonelli, M.
AU - Liguori, R.
AU - Lodi, R.
AU - Carelli, V.
AU - La Morgia, C.
N1 - Ricercatori distaccati presso IRCCS a seguito Convenzione esclusiva con Università di Bologna (Tonon Caterina, Liguori Rocco, Lodi Raffaele, Carelli Valerio, La Morgia Chiara).
PY - 2019/12/30
Y1 - 2019/12/30
N2 - Introduction: Charles Bonnet syndrome is characterized by simple or complex visual hallucinations (VH) due to damage along the visual pathways. We report a functional MRI study of brain correlates of VH in the context of a severe optic atrophy in a patient with Leber's Hereditary Optic Neuropathy (LHON). Case report: A 62-year-old man was diagnosed with LHON (11778/ND4 mtDNA mutation) after subacute visual loss in left eye (right eye was amblyopic). One month later, he experienced VH of a few seconds consisting in "moving red and blue miniature cartoons". One year later VH content changed in colored mosaic (10-15 s duration), usually stress-related, and blue and white flashes (2-5 s), triggered by unexpected auditory stimuli. Audiometry revealed mild sensorineural hearing loss. Three block design functional MRI paradigms were administrated: 1) random "clap", 2) "checkerboard" and 3) non-random "beep". After random "claps" simple flashes were evoked with bilateral activation of primary and secondary visual cortex, cuneus, precuneus and insula. Neither hallucinations nor cortex activation were registered after "checkerboard" stimulation, due to the severe visual impairment. Primary and secondary auditory cortices were "beep"-activated, without eliciting VH by non-random "beep". Conclusions: The peculiarity of our case is that VH were triggered by random auditory stimuli, possibly due to a cross-modal plasticity between visual and auditory networks, likely influenced by the sensorineural deafness. Functional alterations of both networks in resting conditions have been demonstrated in LHON patients, even without an auditory deficit. Finally, the absence of VH triggered by expected stimuli is consistent with the "expectation suppression theory", based on increased neural activations after unexpected but not by predicted events.
AB - Introduction: Charles Bonnet syndrome is characterized by simple or complex visual hallucinations (VH) due to damage along the visual pathways. We report a functional MRI study of brain correlates of VH in the context of a severe optic atrophy in a patient with Leber's Hereditary Optic Neuropathy (LHON). Case report: A 62-year-old man was diagnosed with LHON (11778/ND4 mtDNA mutation) after subacute visual loss in left eye (right eye was amblyopic). One month later, he experienced VH of a few seconds consisting in "moving red and blue miniature cartoons". One year later VH content changed in colored mosaic (10-15 s duration), usually stress-related, and blue and white flashes (2-5 s), triggered by unexpected auditory stimuli. Audiometry revealed mild sensorineural hearing loss. Three block design functional MRI paradigms were administrated: 1) random "clap", 2) "checkerboard" and 3) non-random "beep". After random "claps" simple flashes were evoked with bilateral activation of primary and secondary visual cortex, cuneus, precuneus and insula. Neither hallucinations nor cortex activation were registered after "checkerboard" stimulation, due to the severe visual impairment. Primary and secondary auditory cortices were "beep"-activated, without eliciting VH by non-random "beep". Conclusions: The peculiarity of our case is that VH were triggered by random auditory stimuli, possibly due to a cross-modal plasticity between visual and auditory networks, likely influenced by the sensorineural deafness. Functional alterations of both networks in resting conditions have been demonstrated in LHON patients, even without an auditory deficit. Finally, the absence of VH triggered by expected stimuli is consistent with the "expectation suppression theory", based on increased neural activations after unexpected but not by predicted events.
KW - Charles bonnet
KW - Functional magnetic resonance imaging (fMRI)
KW - LHON
KW - Optic nerve
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U2 - 10.1186/s12883-019-1579-9
DO - 10.1186/s12883-019-1579-9
M3 - Article
C2 - 31888524
AN - SCOPUS:85077320417
VL - 19
JO - BMC Neurology
JF - BMC Neurology
SN - 1471-2377
IS - 1
M1 - 350
ER -