Pure-Tone Hearing Thresholds and Brainstem Auditory Evoked Potentials in Sporadic Ataxia

THIEME e86 Original Research Pure-Tone Hearing Thresholds and Brainstem Auditory Evoked Potentials in Sporadic Ataxia Bianca Simone Zeigelboim1 Anylize Wachholz Vom Scheidt2 Kairone Fernandes Kronbauer2 Paulo Breno Noronha Liberalesso3 Maria Renata José4 Vinicius Ribas Fonseca5 Hélio Afonso Ghizoni Teive5 1 Department of Otoneurology, Universidade Tuiuti do Paraná, Curitiba, PR, Brazil 2 Postgraduation Program in Communication Disorders, Universidade Tuiuti do Paraná, Curitiba, PR, Brazil 3 Department of Pediatric Neurology, Hospital Pequeno Príncipe, Curitiba, PR, Brazil 4 Department of Otorhinolaryngology, Universidade Tuiuti do Paraná, Curitiba, PR, Brazil 5 Department of Neurology, Universidade Federal do Paraná, Curitiba, PR, Brazil Address for correspondence Bianca Simone Zeigelboim, PhD, Postgraduation Program in Communication Disorders, Universidade Tuiuti do Paraná, Rua Sydnei Antônio Rangel, 245 - Santo Inácio, Curitiba, PR, 82010-330, Brazil (e-mail: ). Int Arch Otorhinolaryngol 2020;24(1):e86–e92. Abstract Keywords ► spinocerebellar degenerations ► hearing ► hearing disorders ► audiometry ► evoked response audiometry received January 3, 2019 accepted June 6, 2019 Introduction Spinocerebellar ataxia (SCA) is part of a genetic and clinical heterogeneous group of neurodegenerative diseases characterized by progressive cerebellar ataxia. Objective To describe the results of audiological and electrophysiological hearing evaluations in patients with sporadic ataxia (SA). Methods A retrospective cross-sectional study was carried out with 11 patients submitted to the following procedures: anamnesis, otorhinolaryngological evaluation, tonal and vocal audiometry, acoustic immittance and brainstem auditory evoked potential (BAEP) tests. Results The patients presented with a prevalence of gait imbalance, of dysarthria, and of dysphagia; in the audiometric and BAEPs, four patients presented with alterations; in the acoustic immittance test, five patients presented with alterations, predominantly bilateral. Conclusion The most evident alterations in the audiological evaluation were the prevalence of the descending audiometric configuration between the frequencies of 2 and 4 kHz and the absence of the acoustic reflex between the frequencies of 3 and 4 kHz bilaterally. In the electrophysiological evaluation, the patients presented changes with a prevalence of increased I, III and V wave latencies and the interval in the interpeak I-III, I-V and III-V. In the present study, it was observed that auditory complaints did not have a significant prevalence in this type of ataxia, which does not occur in some types of autosomal recessive and dominant ataxia. DOI https://doi.org/ 10.1055/s-0039-1693676. ISSN 1809-9777. Copyright © 2020 by Thieme Revinter Publicações Ltda, Rio de Janeiro, Brazil Pure-Tone Hearing Thresholds and Brainstem Auditory Introduction Ataxias are a group of neurodegenerative diseases featuring the presence of progressive cerebellar disorder, followed by several neurological signs and symptoms, such as balance and motor coordination disorders, besides the presence of eye dysfunctions.1,2 Ataxias can be divided in six large groups: a) autosomal recessive hereditary ataxias; b) autosomal dominant hereditary ataxias; c) congenital ataxias; d) X-associated ataxia syndrome; e) mitochondrial ataxias; and f) sporadic ataxias (SAs).3–5 The last type is the group of interest in the present study. Sporadic ataxia is classified as a rare neurological condition, of late onset, usually in individuals > 40 years old, with no family history, and with a wide range of potential causes. Among them, cerebellar degeneration, alcohol abuse, paraneoplastic syndrome, heavy metal poisoning (toxic reaction), dysfunction of the neuroimmune system, E, B1, B12 vitamin deficiency, infectious diseases (neurosyphilis, Whipple disease, Lyme disease, and human immunodeficiency virus [HIV]), and degenerative diseases can be pointed out.4,5 Drumond et al6 pointed out the complexity of the differential diagnosis of SA, as well as the difficulty in determining its etiology due to its heterogeneity. When its onset occurs after the age of 50 years old, a wide investigation cannot be enough to detect its etiology; therefore, it can be classified as lateonset idiopathic cerebellar ataxia. Sporadic adult-onset ataxia (SAOA) of unknown etiology is a nonhereditary disorder, distinct from multiple system atrophy. Despite its unknown cause, it is considered as a set of disorders comprising a common clinical syndrome. Epidemiological studies have found prevalence rates ranging from 2.2 to 8.4 per 100,000 individuals. About a third of the SAOA patients have polyneuropathy or affection of the pyramidal tract observed with cerebellar ataxia, although cognitive impairment is not common or present in a mild degree. Neuropathological and imaging studies have shown isolated cerebellar cortical degeneration and mild brainstem atrophy, although there is no established therapeutics for SAOA.4 The neurobiological hearing components involve a complexity of events, as well as broad interrelationships in the central nervous system (CNS).7 Assessment of the peripheral and central hearing systems is performed by means of behavioral, electroacoustic, and electrophysiological tests. Peripheral hearing involves the amplification and conduction of sound waves, as well as the perception of sound vibrations that are changed into nervous impulses. Central hearing involves the conduction of nervous impulses by means of the ear pathway to the hearing cortex, where they will be coded and recoded, thus gaining linguistic meaning. Brainstem auditory responses will be assessed by means of the electrical activities in the auditory nerve. The effects caused by degenerative processes may involve the central auditory nervous system (CANS).8 In some types of cerebellar ataxia, Ikeda et al, Mahmoud, and Zeigelboim et al9–11 had a large percentage of subjects with hearing loss verified through the audiological evaluation. Zeigelboim et al. Some studies,11–13 using electrophysiological tests in patients with cerebellar ataxia, already verified abnormalities in brainstem auditory evoked potentials (BAEPs) in > 50% of the evaluated subjects, while other studies14,15 evidenced abnormality in 71 and 46.5%, respectively, in the BAEP assessment of autosomal recessive and dominant spinocerebellar ataxias. In the acoustic immittance measurement, Zeigelboim et al11 reported disorders in 46.6% of the sample of patients with neurodegenerative diseases, and 44.1% of abnormality in patients with autosomal dominant spinocerebellar ataxia,15 mainly related to acoustic reflexes. Due to the audiological findings found in the literature on the alterations observed in ataxia patients, the present study aimed to describe the results of audiological and electrophysiological screening in patients with SA, which is classified as a rare neurological condition. (...truncated)