Background and Aims:

Three in ten older people (>60 years) complain of persistent dizziness which often remains unexplained despite specialist assessment and vestibular tests. The pathophysiology of such idiopathic dizziness in older people has remained unclear. We investigated if idiopathic dizziness was associated with vascular injury to white matter tracts relevant to balance or vestibular self-motion perception in sporadic small vessel disease.

Methods:

We prospectively recruited 38 vestibular clinic patients with idiopathic dizziness (median 77 years) and 36 asymptomatic controls (median 76 years) who underwent clinical, cognitive, balance, gait and vestibular assessments, and structural and diffusion brain MRI.

Results:

Patients had more vascular risk factors, poorer balance and worse executive cognitive function in association with greater white matter hyperintensity in frontal deep white matter, and lower fractional anisotropy in the genu of the corpus callosum and the right inferior longitudinal fasciculus. Tracts with lower fractional anisotropy in idiopathic dizziness overlapped with those in which lower fractional anisotropy correlated with worse balance across participants. More vestibular symptoms correlated with worse balance in patients. Vestibulo-ocular reflex and perceptual vestibular function was similar in patients and controls, though a white matter network involved in vestibular perception had lower connectivity in patients.

Conclusions:

Our results show a relationship between lower microstructural integrity in frontal balance-relevant white matter tracts in cerebral small vessel disease, poorer balance and idiopathic dizziness. This suggests cerebral small vessel disease may be involved in the pathogenesis of dizziness in some older people.

Background and Aims:

Area OP2 in the posterior peri-sylvian cortex has been proposed to be the core human vestibular cortex. We aimed to clarify the functional anatomy and connectivity of this area.

Methods:

We defined the functional anatomy of OP2 from high resolution functional MRI using spatially constrained independent component analysis on data from the Human Connectome Project. OP2 responses to caloric irrigation and visual motion were then investigated in seventeen controls and seventeen age-matched chronic right vestibular neuritis patients.

Results:

Ten distinct subregions were identified on the basis of varying functional connectivity. Most subregions showed significant connectivity to known vestibular areas, including the parietal opercula, the primary somatosensory cortex, the supracalcarine cortex, the left inferior parietal lobule and the anterior cingulate cortex. In healthy participants, a posterior part of right OP2 showed: (a) direction-selective responses to visual motion; and (b) activation during caloric stimulation that correlated positively with dizziness (perceived self-motion) and negatively with visual dependence. Patients with vestibular neuritis showed abnormal OP2 activity, with an absence of visual or caloric activation and no correlations with dizziness or visual dependence. In contrast, brainstem responses to caloric stimulation measured by peak slow phase nystagmus velocity were normal in the vestibular neuritis patients. A lateral part of right OP2 showed activity that correlated with situational vertigo (chronic dizziness) in patients with vestibular neuritis.

Conclusions:

A posterior subregion of right OP2 shows strong functional connectivity to other vestibular regions and a profile of caloric and visual responses, suggesting a central role for vestibular function in health and disease.

Background and Aims:

Heterozygous mutations in AFG3L2 and ACO2 genes are now associated with Dominant Optic Atrophy (DOA). We aimed at describing their neuro-ophthalmological phenotype compared with OPA1-DOA.

Methods:

OPA1-negative DOA patients were investigated by multigenic targeted panel. Missense mutations were differentiated from those causing haploinsufficiency. Neuro-ophthalmological exam included fundus, visual acuity (VA), colour vision, visual field (VF), optical coherence tomography (OCT) of retinal nerve fiber layer (RNFL) and ganglion cell layer (GCL).

Results:

We collected 22 ACO2-DOA and 13 AFG3L2-DOA, compared with 104 age-matched OPA1-DOA. 10 ACO2, 23 OPA1 and all AFG3L2 patients had missense mutations, the remaining ACO2 and OPA1 had haploinsufficiency mutations. The majority of patients presented vision loss and impaired color vision with central scotoma, temporal or diffuse optic nerve pallor at fundus, similar RNFL and GCC layer defect at OCT. However, ACO2-DOA had worse VA and foveal threshold at VF only in OD. At OCT, ACO2-DOA had significantly higher thickness is nasal RNFL and in all GCL sectors in both eyes compared to OPA1- and AFG3L2-DOA. Moreover, we confirmed that OPA1-DOA with missense mutation are more severe than those with haploinsufficiency. The same, even if not significant, was observed in ACO2-DOA with missense mutation.

Conclusions:

Overall, neuro-ophthalmological phenotype of AFG3L2-DOA is indistinguishable from OPA1-DOA, whereas ACO2-DOA had worse visual function in a setting of a less severe and more selective optic atrophy. Missense mutations are associated to a more severe phenotype in both OPA1- and ACO2-DOA.

Background and Aims:

Recently, spread of the video-head impulse testing (vHIT) device enables clinicians to assess the function of the vertical semicircular canals. The posterior semicircular canal (PSC) has different blood supply, different innervation and different position from the lateral and anterior semicircular canals (LSC and ASC). Therefore, isolated posterior semicircular hypofunction may be caused more frequently than the lateral and anterior semicircular canals. However, the clinical features of isolated posterior semicircular canal hypofunction (IPH) and its etiology have not been fully investigated. This study was performed to clarify clinical features and etiology of acute unilateral IPH.

Methods:

From the data base of our clinic patients with unilateral IPH were selected. Their clinical records including vHIT, VEMP and audiometry were reviewed. The lower limits of the normal range of VOR gain were set as 0.7 for PSC and ASC and 0.8 for LSC.

Results:

Twenty-four patients were found as having unilateral IPH. Among the 24 patients, 11 patients had acute unilateral IPH. Among the 11 patients, 7 patients were accompanied by ipsilateral sudden hearing loss and 4 patients did not have associated hearing loss. Their hearing losses was dominant at high frequencies. Majority of patients had normal cVEMP (cervical vestibular evoked myogenic potential).

Conclusions:

These findings suggested that acute unilateral IPH might be caused by ischemia in the vestibulo-cochlear artery and that ischemia in the proximal site of (VCA) might result in IPH with hearing loss while ischemia in the distal site might result in pure IPH.

Background and Aims:

Benign paroxysmal positional vertigo (BPPV) is the most common peripheral vestibular diagnosis in acute TBI. However, there is a paucity of acute prospective data regarding the most effective treatment, optimal time to treat and recurrence. Given such uncertainties we aimed to investigate the feasibility of assessing and treating BPPV in acute TBI.

Methods:

Participants were recruited from two major trauma centres in London, UK. Inclusion criteria included those over the age of 18, with a closed head injury (as noted by CT scan) and were an inpatient on a major trauma or outlying ward. Importantly, subjective dizziness was not a prerequisite for inclusion. Following consent, patients were assessed for BPPV by trained ward therapists. Those with BPPV were randomly allocated to one of three interventions (repositioning manoeuvres, Brandt Daroff exercises or advice) and were followed up at two time intervals.

Results:

95 patients have consented to take part in the study. Of those, BPPV was diagnosed in twenty eight (mean age 50 years; 20 males, 8 females). 62% of patients had a moderate-severe head injury. 14 (50%) had unilateral BPPV, of which 71% had right sided posterior canal BPPV. 12 patients (43%) had bilateral posterior canal BPPV.

Conclusions:

This is the first data from a prospective study investigating BPPV in acute TBI. Initial data suggests just under a third of patients with acute TBI have BPPV. Interestingly, a large number of patients had bilateral BPPV. Data from this study will inform a more definitive randomised controlled trial.

Background and Aims:

Introduction:The analysis of the ophthalmological outcome to prove the effect of functional recovery by minimal invasive neurosurgical procedures (MIN) enclosed 9 cases of ICH (intracerebral hemorrhage) with occipital/parieto-occipital locations and 8 cases of tumor-/liquor dynamics-diseases causing disturbance of visual function.

Methods:

Materials and methods: This concept combined 5 MIN-key techniques to assist microneurosurgery: high-end neuro-sonography with small probes, mouth-tracking of the microscope -both mandatory-, endoscopy and LASER. Sealing technique was always used.

Ophthalmological standard techniques were perioperatively used to meticulousely document ophthalmological functions. Visual acuity, 30°-visual field, RNFL and fundoscopy were examined as soon as the patients´ condition did allow so.

Results:

In the occipital/ parieto-occipital hemorrhage group there were 5 males, 3 females and 1 baby. The hemorrhage volume was 20–125 ml, localized 0–1,5 cm depth from the cortex. Sono-assisted and mouth-tracked microsurgery through seven MIN approaches of 1–3 cm diameters and two burr-holes of 1 cm diameter were used. All 9 ICH-patients recovered in visual function fastly. In the tumor-/liquor dynamics-disease group were 4 males and 4 females. Reasons of the liquor-pathway-obstruction were: 7 tumors, 1 cyst, 6 hydrocephaly, 2 post-ICH cases and 3 complex cases. 7 of them were emergency cases regarding preservation of visual function.

In both groups, visual function recovery could be documented.

Conclusions:

- Cooperation of neurosurgery and ophthalmology can preserve visual functions, even in

emergency cases.

- Ophthalmological techniques may support the outcome analysis as an excellent model to

show functional recovery after ICH-evacuation and procedures of tumor-/liquor dynamics-

diseases.

Background and Aims:

1) Identifying how age, global positioning systems(GPS) use and vestibular navigation influence sense of direction(SOD). 2) Investigating vestibular navigation in patients with downbeat nystagmus (DBN; floculo-nodular damage) to see if vestibulo-cerebellar ascending pathways carry orientation/position signals

Methods:

We applied two navigation tasks on a rotating chair in the dark: return-to-start (RTS), where subjects drive the chair back to origin after discrete angular displacements(path reversal), and complete-the-circle (CTC) where subjects drive the chair all the way round to origin(path completion). We tested 24 normal controls (age-range:20-83years), 5 patients with DBN(62-75years) and, as a pilot, 2 patients with early Alzheimer’s disease. Santa Barbara SOD questionnaire (SBSOD) and GPS use were measured.

Results:

SOD is influenced by age(p =.08), GPS use(p<0.05) and by vestibular navigation performance, particularly CTC-task(p<0.05). A trend for age-related decline in vestibular navigation during RTS task was observed(p=.06) but not for the complex CTC-task(p=.74). In DBN patients vestibular navigation was normal but, in patients with Alzheimer’s disease, RTS and particularly CTC results were grossly abnormal.

Conclusions:

Vestibular navigation skills contribute to our SOD. SOD does not decay in the elderly; probably explained by increased use of GPS by the young, as GPS inhibit SOD. The discrepancy between age-effect in RTS but not CTC likely reflects a parallel process of central compensation as presbivestibulopathy advances. Normal navigation in DBN patients suggests that vestibular-cerebellar pathways only carry velocity(not position) signals. The clear abnormalities in patients with AD indicate that spatial disorientation in AD is not only visuo-spatial but also vestibulo-spatial.