15381Journal ofNeurology, Neurosurgery, and Psychiatry 1994;57:1538-1540 SHORT REPORT Click-evoked vestibular activation in the Tullio phenomenon J G Colebatch, J C Rothwell, A Bronstein, H Ludman Abstract Subjects and methods Click-evoked vestibulocollic reflexes CASE HISTORY were studied in a patient with a unilat- The patient, a 55 year old woman, reported eral Tullio phenomenon (sound induced that she had experienced left retroauricular vestibular symptoms) and the findings pain and impaired balance after a series of were compared with those of a group of forceful sneezes six years previously. Pressure normal subjects. Compared with normal over the mastoid area or loud sounds made subjects, the reflexes elicited from her her feel unsteady and veer to the left, and also symptomatic side were large and had an made her retroauricular pain worse. abnormally low threshold, but retained Associated with these symptoms was the illu- a normal waveform. The click-evoked sion of objects "swimming" in front of her. responses in this patient show changes Clinical examination of her eye movements as consistent with her symptomatology and well as the remainder of the neurological are indicative of a pathological increase examination were normal. The Hallpike in the normal vestibular sensitivity to manoeuvre was negative bilaterally. Loud sound. tones (1 kHz, 110 dB ISO) presented to the left ear through earphones caused visible nys- (7 Neurol Neurosurg Psychiatry 1994;57: 1538-1540) tagmus. This consisted mainly of conjugate torsional left beating and down beating com- ponents.11 Similar loud sounds presented to Patients with the Tullio phenomenon experi- the right ear did not cause nystagmus. Pure ence vestibular symptoms when they hear tone audiograms, stapedial reflex thresholds, specific, usually loud, sounds. Reported pre- bithermal caloric tests, CT of the temporal cipitants include rumbling noises of traffic bone, and cranial MRI were normal. The and trucks, noises of a crowded bazaar,' cam- middle ear was normal when surgically panology (bell ringing),2 car horns,3 and say- explored (HL). ing certain vowels.45 Clinically it is possible to Click stimuli were delivered through ear- induce nystagmus in these patients with phones with the patient sitting.10 Surface sound, which, although loud, has no such EMG recordings were made over the right effect in control subjects. and left sternocleidomastoid muscles with a Very loud sounds (over 130 dB SPL) can reference electrode over the sternoclavicular cause vestibular symptoms in normal sub- joint and the active electrode over the muscle jects,58 but usually these intensities are only belly (interelectrode distance 6-8 cm). Clicks achieved near jet engines or explosives. It is 0-1 ms long were applied at 3/s pseudoran- thought that, under these conditions, the domly to either the right or left ear. The click sound pressure wave set up in the inner ear generator was purpose built and calibrated to of Department can directly activate vestibular receptors. By produce clicks from 70 dB to 100 dB above Neurology, Prince of dB NHL = 45 Wales Hospital, making the sound duration very short normal hearing threshold (0 Randwick NSW 2031, (clicks), these high sound intensities can be dB SPL for 0 1 ms click). In this report, Australia presented safely.9 Colebatch et al'0 showed sound intensities are measured with respect J G Colebatch that loud clicks evoked a short latency EMG to (normal) hearing threshold as this is the MRC Human in the contracting sternocleidomas- common method by which commercial click Movement and response to Balance Unit, toid muscles and presented evidence that this generators are calibrated. It is important National Hospital, represented a vestibulocollic reflex, possibly note that impulse noise intensity is formally Queen Square, originating from saccular afferents. Given defined in dB SPL9 and this physical rather London WC1N 3BG, is the more relevant UK these findings, it is natural to speculate than perceptual intensity J C Rothwell whether the Tullio phenomenon simply rep- to the effects on the vestibular apparatus. A Bronstein of the normal condi- The patient was instructed to activate her Ludman resents an exaggeration H tion (a lower threshold than normal for neck flexors tonically. Averages of both Correspondence to: EMG were made Dr J G Colebatch, acoustic activation of the vestibular appara- unrectified and rectified = Department of Neurology, or whether there might also be a more (n 256) with a laboratory interface and Institute of Neurological tus) Sciences, Prince of Wales fundamental alteration in the nature of the associated commercial software (SIGAVG Hospital, High Street, vestibular activity induced by sound in these Ver 6-0, Cambridge Electronic Devices, Randwick, Sydney NSW were Australia. patients. We have recently had the opportu- Cambridge, UK). The patient's results 2031, volunteers Received 14 April 1994 nity of applying this new technique in a compared with those of 25 normal and in revised form patient with an established Tullio phenome- (ages 22 to 65) tested under similar condi- 18 June 1994. a commercial click generator Accepted 28 June 1994 non to consider this issue. tions but with Click evoked vestibular activation in the Tullio phenomenon 1539 Recordings madefrom over A B the patient's right sternocleidomastoid (A) ear and left Right Left ear sternocleidomastoid muscle />>,7070 dB (B). In each case, the "I averaged effects of stimulating the ipsilateral ear are shown. The effects of unilateral clicks of three different intensities are illustrated. Click intensities are given relative to the reference intensity (45 dB 90 dB SPL: see text). All averages were made ofthe effects of256 presentations of the click stimulus which was given 20 ms after the traces began, at time = 0. Positive potentials at the active electrode caused a downward deflection. When the symptomatic 100dB (left) ear was stimulated, a clearp13-n23 response was visible with lowest intensity used (70 dB), a lower level than for any ofthe normal subjects tested. By contrast, the p13-n23 response on -20 0 20 40 60 80 -20 0 20 40 60 80 the right side was onlyfirst seen with 90 dB clicks. Time (ms) (ST10: Medelec, Surrey, UK). Peaks of the sity stimulus (70 dB) and increased in ampli- evoked waveforms have been described with tude and saturated with 90 dB clicks. Peaks the nomenclature of Colebatch et al in which consistent with n35 and p4410 were present the p13-n23 biphasic wave in the unrectified after the more intense stimuli. The p13-n23 average is specifically generated by vestibular response on the right side began with 90 dB afferents.'0 The size of the p13-n23 response clicks and increased in size with louder clicks is proportional to the level of tonic muscle but was always much smaller than on the left. activation10 and to allow for this reflex ampli- The latency of the initial positivity was tudes have also been expressed as a ratio of slightly longer on the left than on the right the average level of the (prestimulus) rectified (16-6 v 12-2 ms). There was no sensation of EMG. vertigo or visible eye or head movement dur- ing click testing. All the normal volunteers had p 1 3-n23 Results responses when given stimuli at 100 dB but The responses evoked by stimulation of the none had responses at 70 dB (mean thresh- patient's right and left ears were different old: right 87 dB, left 86 dB). The two normal (figure) and the table summarises these. The subjects with the lowest thresholds had small vestibular dependent p13-n23 response was responses to 75 dB clicks, with corrected present on the left side with the lowest inten- amplitudes smaller (0-35-0-51) than those seen in the patient with 70 dB clicks. The size of the patient's left sided response, corrected for background activity, was also larger than that in any control subject at an intensity of 80 dB. At intensities of 90 dB and higher, Click induced vestibulocollic reflexes in left Tullio phenomenon p13-n23 responses similar in amplitude to those of the patient were sometimes found in Right Left normal subjects: thus for 100 dB clicks, Intensity Rect EMG Rect EMG corrected amplitudes over 2-37 (the maxi- (dB NHL) p131n23 (uV) Ratio p13-n23 (AT-9 Ratio mum size of the patient's response) were 70 - - - 51-2 68-9 0 74 recorded from three normal volunteers (four 80 - - - 79-7 59-8 1-33 90 12-7 72-2 0-18 152-2 69-4 2-19 ears). The threshold difference between the 95 24-9 81-1 0-31 191-7 88-5 2-17 ears for eliciting the p13-n23 response was 100 37.9 82-6 0-46 191-3 80-7 2-37 never greater than 10 dB in the normal The intensity of the clicks (0-1 ms duration) is given in the left column where 0 dB NHL = 45 volunteers. dB SPL. The three columns thereafter detail the vestibulocollic reflexes recorded from the right sternocleidomastoid muscle in response to clicks given to the right ear. The last three columns give the same results for clicks given to the left ear, using recordings made over the left ster- nocleidomastoid. The peak to peak amplitude of the pl3-n23 response'° is given first, then the mean rectified EMG, and finally the size of the response as a ratio of the background EMG Discussion activity. The threshold and amplitudes on the right side were within the range of the normal Colebatch et al10 presented evidence, based controls. On the left, the response began at a lower threshold than normal and was correspond- ingly larger. Correction for background activity indicated that the size of the response on the on changes seen in patients with selective 8th left became saturated at 90 dB.