Search results for " Brain Stem"

Hearing Without Neuroglobin.

2017

Abstract Neuroglobin (Ngb) is a member of the globin family of respiratory proteins, which was recently observed in many neurons of the auditory pathways. Up to now, however, nothing was known about the role of Ngb in hearing processes. We therefore studied auditory function by recording distortion-product otoacoustic emissions (DPOAE) and auditory brainstem responses (ABRs) in wild-type (C57BL/6N) and Ngb-knockout mice. In KO mice, DPOAE thresholds were moderately augmented in the range of 5–18 kHz, reaching statistical significance at 8 and 10 kHz, while the ABR thresholds were not different between groups. The activation of the efferent system by an additional noise given to the contrala…

Quantity language speakers show enhanced subcortical processing

2016

Abstract The complex auditory brainstem response (cABR) can reflect language-based plasticity in subcortical stages of auditory processing. It is sensitive to differences between language groups as well as stimulus properties, e.g. intensity or frequency. It is also sensitive to the synchronicity of the neural population stimulated by sound, which results in increased amplitude of wave V. Finnish is a full-fledged quantity language, in which word meaning is dependent upon duration of the vowels and consonants. Previous studies have shown that Finnish speakers have enhanced behavioural sound duration discrimination ability and larger cortical mismatch negativity (MMN) to duration change comp…

Confirmation of PDZD7 as a Nonsyndromic Hearing Loss Gene.

2016

Objective PDZD7 was identified in 2009 in a family with apparent nonsyndromic sensorineural hearing loss. However, subsequent clinical reports have associated PDZD7 with digenic Usher syndrome, the most common cause of deaf-blindness, or as a modifier of retinal disease. No further reports have validated this gene for nonsyndromic hearing loss, intuitively calling correct genotype-phenotype association into question. This report describes a validating second case for biallelic mutations in PDZD7 causing nonsyndromic mild to severe sensorineural hearing loss. It also provides detailed audiometric and ophthalmologic data excluding Usher syndrome in both the present proband (proband 1) and the…

Abnormal BAEP and internal auditory canal MRI in intracranial hypotension

2017

Intracranial hypotension (IH) is a treatable condition due to cerebrospinal fluid leak, characterised by variable clinical and MRI findings.1 Positional headache, neck stiffness, hearing changes with subdural fluid collection, enhancement of meninges, engorgement of venous structures and brain sagging are among the most frequent clinical and MRI findings. Typical abnormalities are found in 68%–85% of patients1. Hearing alterations (ranging from misperception to severe hearing loss) are known clinical symptoms of IH.1 The mechanism involves secondary perilymph depression due to patency of the cochlear aqueduct, inducing a compensatory expansion of the endolymphatic compartment, decreasing ba…

Separate and Combined Effects of a Benzodiazepine (Alprazolam) and Noise on Auditory Brainstem Responses in Man

1999

Auditory brainstem responses (ABRs) were recorded in 60 male or female, anxious or anxiety-free university students, before and after separated or simultaneous intake of alprazolam and exposure to noise. A significant increase of the latencies of the ABRs was found when subjects took alprazolam. This effect is consistent with the presence of gamma-aminobutyric acid (GABA), one of the neurotransmitters at terminals of cochlear efferent fibres A significant increase of the latencies was observed after noise alone. In subjects taking alprazolam when they are exposed to noise, the effect of noise on the ABR latencies is reduced, but not abolished. The effects of alprazolam on the ABR are consis…

Assessment of brainstem function in Chiari II malformation utilizing brainstem auditory evoked potentials (BAEP), blink reflex and masseter reflex

2000

Brainstem dysfunction was evaluated in 67 patients with myelomeningocele and Chiari II malformation using brainstem auditory evoked potentials (BAEP), blink reflex (BR) and masseter reflex (MR). Signs and symptoms related to Chiari II malformation were observed in 18 patients while 49 patients had normal brainstem findings. BAEP and BR showed a higher sensitivity of brainstem involvement than MR (BAEP=1.0, BR=0.83, MR=0.50). BR, and in particular, MR were of higher accuracy (BR=0.52, MR=0.72) than BAEP (0.39) in separating patients with brainstem signs and symptoms related to Chiari II malformation. We feel that this is due to anatomic and physiologic peculiarities of the brainstem structur…

Topodiagnostic implications of hemiataxia: An MRI-based brainstem mapping analysis

2007

The topodiagnostic implications of hemiataxia following lesions of the human brainstem are only incompletely understood. We performed a voxel-based statistical analysis of lesions documented on standardised MRI in 49 prospectively recruited patients with acute hemiataxia due to isolated unilateral brainstem infarction. For statistical analysis individual MRI lesions were normalised and imported in a three-dimensional voxel-based anatomical model of the human brainstem. Statistical analysis revealed hemiataxia to be associated with lesions of three distinct brainstem areas. The strongest correlation referred to ipsilateral rostral and dorsolateral medullary infarcts affecting the inferior ce…

Electrophysiological and MRI findings in 2 patients with Listeria rhombencephalitis.

1997

Brainstem evoked potentials and magnetic resonance imaging abnormalities in differential diagnosis of intracranial hypotension.

2019

Summary Objective To compare brainstem acoustic evoked potentials (BAEP) and magnetic resonance imaging (MRI) in the differential diagnosis of intracranial hypotension (IH), Chiari malformation (CM) and sensorineural hearing loss (SNHL). Methods BAEP were recorded in 18 IH, 18 CM, 20 SNHL patients and 52 controls. MRI were acquired in all IH and CM patients. Results Abnormal BAEP were observed in 94% of IH patients, in 33% of CM and 70% of SNHL patients. After recovery from IH, BAEP abnormalities disappeared. Internal auditory canal (IAC) MRI abnormalities were described in 88% of IH patients. MRI signs of IH were observed in 33–78% in IH patients, but the most frequent MRI sign was 8th ner…

Isolated cranial nerve palsies in multiple sclerosis

1997

During a 10 year period 24 patients with definite multiple sclerosis with isolated cranial nerve palsies were studied (third and fourth nerve: one patient each, sixth nerve: 12 patients, seventh nerve: three patients, eighth nerve: seven patients), in whom cranial nerve palsies were the presenting sign in 14 and the only clinical sign of an exacerbation in 10 patients. MRI was carried out in 20 patients and substantiated corresponding brainstem lesions in seven patients (third nerve: one patient, sixth nerve: four patients, eighth nerve: two patients). Additional abnormal findings of electro-oculography, or masseter reflex, or blink reflex, or combinations of these were found in 20 patients…