Perceived direction of gravity and the body-axis during static whole body roll-tilt in healthy subjects

Objective: We used the subjective visual vertical (SVV) and two different subjective visual body axis (SVBA) methods to quantify roll-tilt perception under gravity, and investigated the characteristics of these methods during static roll-tilt. In addition, we independently developed a compact device to facilitate evaluation of SVBA in different gravitational environments.

Methods: Ten male volunteers participated in this study. We created a roll-tilt environment using a flight simulator in a dark room. The cockpit of the simulator was tilted leftward or rightward (?30°,??20°,??10°, 0°, 10°, 20° and 30°) in each randomly ordered trial. We quantified roll-tilt perception such that the experiment was conducted under 21 different conditions per participant.

Results: We found no significant differences among the SVV error and the two types of SVBA error.

Conclusions: The SVV and the SVBA methods may be useful for evaluating subjective roll-tilt perception.     

Evaluation and interpretation of the bucket test in healthy individuals*

Objective: To determine and interpret the range of normal deviation of the bucket test in healthy subjects

Subjects and methods: Study design: Cross-sectional study in a secondary care center. Inclusion criteria: subjects ≥18 years old with no otologic or neurologic symptoms and normal complete neuro-otological examination. The subjective visual vertical was evaluated binocularly using the bucket test. Five measurements were made on the clockwise direction and five on the counterclockwise direction. The examiner selected the starting point, the patient then manipulated the bucket and it stopped when the volunteer considered the line reached the vertical position.

Results: Fifty healthy volunteers were included, 16 (32%) were men, and 34 (68%) women with a mean age of 34 years. The mean value found clockwise was 1.93°?±?2.26° and counterclockwise sense was of 0.86°?±?2.44°. Mean normal values ranged from 1.4°?±?1.9°.

Conclusions: The bucket test is easy and quick to perform; we recommend to use a range of ?1.0° to +3.0° as normal values in the healthy population.     

Testing utricular function by means of on-axis rotation

Conclusions. Subjective visual vertical (SVV) estimation during on-axis rotation provides an efficient screening test of utricle function. The survey demonstrates that isolated disorders of peripheral utricular function can occur while SCC function appears normal. Objective. The present study aimed to investigate estimation of SVV during constant velocity yaw rotation (with the head held on-axis – to enhance any asymmetry between right and left utricular responses), as a useful screening test. Materials and methods. In all, 230 patients were recruited from the dizziness clinic. For each patient, the SVV was estimated (a) while held stationary, and (b) during constant angular velocity (240°/s), with the head centred on-axis. Bithermal caloric testing was also performed in 201 of the patients. Results. Of those patients with normal SVV results during stationary testing, 18.3% were pathological during rotation testing. In those cases with pathological SVV during stationary testing, a significantly greater deviation from the norm was observed during rotation (p<0.001). Of those patients with normal caloric responses, 44.4% showed pathological SVV estimates; this increased to 54.3% for cases with unilateral weakness, and 56.5% for unilateral loss. No clear correlation was found between reports of tilt illusion and pathological SVV, respectively, between rotatory vertigo and pathological caloric responses.     

Utricular paresis and semicircular canal hyperactivity: a distinct otolith syndrome

Conclusions: Although combined utricular and canal paresis has been described previously, this is the first report of canal hyperactivity associated with utricular hypofunction. Unsteadiness and swaying were the most common symptoms, and patients with shorter duration of symptoms also had positional vertigo. We propose that this syndrome is a variant of utricular dysfunction and should be considered in the differential diagnosis of peripheral vestibular disorders. Objective: To describe a syndrome of instability associated with utricular dysfunction and hyperactive caloric responses. Methods: The study comprised 11 consecutive patients exhibiting abnormalities of the eccentric subjective visual vertical test (e-SVV) and high responses during the caloric test of the videonystagmography (VNG). We carried out a review of symptoms, physical examination, and vestibular tests. Results: There was no gender predilection or obvious etiology. The patients’ main complaint included instability with linear symptoms (i.e., tilting, rocking, and swaying), with positional vertigo as a secondary symptom. Oculomotor testing, visual fixation index, and brain MRI were normal, excluding a central nervous system disorder. VNG was essentially normal except for hyperactive responses during the caloric testing in all patients. Abnormal e-SVV was found in 10 patients unilaterally and bilaterally in 1 patient. Abnormal oVEMP was found in seven of seven patients, further supporting a utricular site of lesion.