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West Nile virus (WNV), is an emerging virus [1]. Most human infections are subclinical or manifest as a mild febrile illness, while fewer than 1% develop a neuroinvasive disease (WNND), including meningitis, encephalitis, and/or an acute flaccid paralysis (AFP) [2–4]. We describe a case of sensorineural hearing loss (SNHL) secondary to WNV infection. A 55 year-old previously healthy and normoacousic man, was admitted (in September 2010) for bilateral hearing loss and leg weakness. He complained, about 2 weeks before, of malaise, fever, generalized fatigue, and diffuse myalgias, initially attributed to a flu-like syndrome. After a few days he noted a mild weakness in both of his legs evolving over a week into a flaccid paraparesis. At the same time, he also developed a sudden bilateral hearing loss. He was afebrile, with stable vital signs. Routine and immunological laboratory data were within the normal range. Neurologic examination was remarkable for a flaccid areflexic paraparesis, weakness being more pronounced in the right leg and proximally (3/5 strength in the right leg, 4/5 strength in the left leg), with flexor plantar responses. No cranial nerve involvement, vestibular, cerebellar, brainstem or meningeal signs were noted. MRI of the brain and whole spine was normal without meningeal, parenchymal or ventral nerve root enhancement. Audiological tests, including the Weber and Rinne tuning fork tests, pure tone and speech audiometry, tympanic admittance, auditory evoked potentials (ABRs) and a screening test for acoustic emissions (OAEs), demonstrated a bilateral, down-sloping SNHL—mild on the left side, severe on the right—with normal acoustic admittance, and impaired OAEs, which were absent in the right ear. Weber test was lateralized to the left side, and the Rinne test was not significant. ABR with click at maximum output level (125 dB SPL) was not evocable by stimulating the right ear and normal for the left ear after latencies correction for the hearing threshold elevation. On the whole, the data were compatible with a bilateral asymmetric cochlear damage. Electrodiagnostic studies showed normal sensory and motor nerve conductions, and moderate decrease of compound motor action potential amplitudes. Late responses were normal. Concentric needle electromyography showed active denervation with a neurogenic recruitment pattern in all four limbs, with a clear predominance in legs. The findings fulfilled the diagnostic criteria for WNV AFP [4, 5]. Neurophysiological examination of cranial nerves and brainstem reflexes studies gave normal results. Since the symptoms began during a work-related stay in Romania where a WNV infection outbreak was occurring [6, 7], we considered the above infection in the differential diagnosis. Serum IgM and low-avidity IgG WNV-specific antibodies were detected (titre:1:1,600; 1:51,200, respectively). The presence of IgMand low avidity IgG WNV-specific I. Casetta (&) E. Cesnik Section of Neurology, Department of Medical and Neurological Sciences of Communication and Behaviour, University of Ferrara, Corso della Giovecca 203, 44121 Ferrara, Italy e-mail: cti@unife.it

Two neuro-ophthalmological syndromes due to paramedian pontine infarction have previously been described. The ‘‘one and a half’’ syndrome was first reported and named by Miller Fisher [1], and consists of horizontal gaze palsy combined with an ipsilateral inter-nuclear ophthalmoplegia (INO) resulting in loss of all horizontal eye movements except abduction of the contralateral eye. The causative lesion is usually within the ipsilateral pontine tegmentum and is due to involvement of the abducens nucleus plus the medial longitudinal fasciculus (MLF), or alternatively to involvement of the MLF plus the paramedian pontine reticular formation (PPRF). These structures lie in close proximity to the nucleus and intra-axial fasiculus of the facial nerve. Consequently, ipsilateral fascicular lower motor neurone facial nerve palsy may accompany the ‘‘one-and-a-half’’ syndrome. This situation was named the ‘‘eight and a half syndrome’’ by Eggenberger [2], who reported 3 cases of this syndrome that had occured secondary to ischaemic stroke. In continuation of this concept, we here describe the ‘‘sixteen and a half syndrome’’, which is the ‘‘one and a half’’ syndrome with an additional 7th and 8th cranial nerve (vestibulo-cochlear nerve) palsy. A 78-year-old right-handed man presented with sudden onset of incomplete right upper limb paresis, horizontal diplopia and ataxia. This was shortly followed by complete right lower limb paresis. There was associated nausea and vomiting. Examination revealed a left-sided lower motor neurone facial nerve palsy and dysarthria with loss of conjugate gaze to the left and loss of adduction of the left eye. Abduction of the right eye was accompanied by horizontal nystagmus. Convergence was spared. The patient also complained of new-onset left-sided hearing loss. The patient and his family were certain that his hearing before this event had been normal. Magnetic resonance imaging (MRI) with diffusion-weighted sequences revealed an area of restricted diffusion consistent with an acute infarct. The lesion extended beyond and lateral to the paramedian pontine territory supplied by the anteromedial group of pontine perforating arteries, and dorsally to the fourth ventricle and the region of the facial colliculus (Fig. 1a, b). Pure tone audiometry showed no detectable hearing in the left ear. Brainstem auditory evoked potential testing showed no reproducible wave I, wave III or wave V after left ear stimulation. Waves I, III and V from right ear stimulation were of low amplitude with normal absolute and interwave latencies. Eight months later, the Weber test lateralized to the right ear, and the Rinne test revealed absent air-conducted and bone-conducted sound perception in the left ear. Our patient had an ‘‘eight and a half’’ syndrome plus additional ipsilateral hearing loss. We name this clinical entity the ‘sixteen and a half syndrome’. Hearing loss has not previously been described in association with either ‘‘one and a half’’ or ‘‘eight and a half’’ syndrome. A clinical series of 20 cases of ‘‘one and a half’’ syndrome noted G. Cummins R. Dunne K. O’Rourke (&) T. Lynch Dublin Neurological Institute, Mater Misericordiae University Hospital, 57 Eccles St., Dublin 7, Ireland e-mail: killian.orourke@gmail.com