Role of cervical vestibular evoked myogenic potentials (cVEMP) and auditory brainstem response (ABR) in the evaluation of vestibular schwannoma / Papel dos potenciais evocados miogênicos vestibulares cervicais (cVEMP) e potencial evocado auditivo de tronco encefálico (PEATE) na avaliação do schwannoma vestibular

Abstract Introduction: Cervical vestibular evoked myogenic potentials (cVEMP) can assess the integrity of the inferior vestibular nerve thereby promising to be a useful tool in the audiological test battery to diagnose vestibular schwannoma. Objective: To ascertain the utility of cVEMP in diagnosis of vestibular schwannoma in conjunction with the ABR and to evaluate whether the size of lesion has any effect on the cVEMP measures. Methods: Case-files of 15 known cases of vestibular schwannoma whose pure tone audiometry, auditory brainstem response (ABR), cVEMP and radiological investigation findings were available, were included in the study. Patients were categorised as large or small tumours based on the size. The absolute and inter-peak latencies of ABR, amplitudes of waves V and I, and inter-aural latency difference of wave V of ABR; and latency of P1 and N1 of cVEMP and amplitude of P1-N1 complex were considered in the study. Results: There were eight large and nine small tumours. All the patients with large tumours showed significant severity of hearing loss whereas only three out of nine patients with small tumours showed severe to profound deafness in the affected ear. The rest showed hearing status ranging from normal hearing sensitivity to moderate hearing loss. Most of the patients with large tumours showed complete absence of ABR in the affected ears with no identifiable wave-peaks. ABR in small tumours exhibited delayed III-I and delayed V-I interpeak latency interval (IPL). Four out of five patients with large unilateral tumours revealed contralateral effects of reduced amplitude or absence of cVEMP. On the contrary, six out of eight unilateral small tumours showed a normal cVEMP response in the contralateral ear. Both the patients with NF2 in the present study demonstrated cVEMP abnormalities. Conclusion: ABR and cVEMP, when used in combination, can be of immense use in identification of neuro-otologic conditions such as vestibular schwannoma and bilateral tumours in NF2. In the evaluation of unilateral vestibular schwannoma, abnormal contralateral findings of cVEMP and ABR are strongly indicative of the tumour size >2.5 cm. In unilateral severe to profound loss wherein ABR in poorer ear cannot give information of site-of-lesion, cVEMP can help in the differentiation.

Resumo Introdução: Os potenciais evocados miogênicos vestibulares cervicais (cVEMP) podem avaliar a integridade do nervo vestibular inferior, prometem assim ser uma ferramenta útil na bateria de testes audiológicos para o diagnóstico de schwannoma vestibular. Objetivo: Determinar a utilidade de cVEMP no diagnóstico de schwannoma vestibular em conjunto com PEATE e avaliar se o tamanho da lesão tem qualquer efeito sobre as medidas do cVEMP. Método: Quinze casos diagnosticados com schwannoma vestibular cujos exames de audiometria tonal pura, potencial evocado auditivo de tronco encefálico (PEATE), cVEMP e investigação radiológica estavam disponíveis foram incluídos no estudo. Os pacientes foram classificados como portadores de tumores grandes ou pequenos. As latências absolutas e interpico de PEATE as amplitudes das ondas V e I e a diferença de latência interaural da onda V da PEATE e a latência de P1 e N1 de cVEMP e amplitude do complexo P1-N1 foram consideradas no estudo. Resultados: Havia oito tumores grandes e nove pequenos. Todos os pacientes com tumores grandes apresentavam perda auditiva grave enquanto apenas três dos nove pacientes com pequenos tumores apresentaram surdez grave a profunda na orelha acometida. O restante apresentou audição que variou de normal a perda auditiva moderada. A maioria dos pacientes com tumores grandes demonstrou ausência completa de PEATE nas orelhas acometidas sem picos de onda identificáveis. O PEATE em tumores pequenos apresentou intervalo de latência interpico (ILI) tardia III-I e tardia V-I. Quatro em cada cinco pacientes com tumores grandes unilaterais revelaram efeitos contralaterais de amplitude reduzida ou ausência de cVEMP. Ao contrário, seis dos oito tumores pequenos unilaterais apresentaram resposta de cVEMP normal na orelha contralateral. Ambos os pacientes com NF2 no presente estudo demonstraram anormalidades na cVEMP. Conclusão: PEATE e cVEMP, quando usadas em combinação, podem ser úteis na identificação de condições neuro-otológicas como schwannoma vestibular e tumores bilaterais em NF2. Na avaliação de schwannoma vestibular unilateral, achados contralaterais anormais de cVEMP e PEATE são fortemente indicativos de tumor >2,5 cm. Na perda unilateral grave a profunda, na qual o PEATE na orelha mais prejudicada não fornece informações do local da lesão, cVEMP pode ajudar na diferenciação.

Role of cervical vestibular evoked myogenic potentials (cVEMP) and auditory brainstem response (ABR) in the evaluation of vestibular schwannoma.

INTRODUCTION: Cervical vestibular evoked myogenic potentials (cVEMP) can assess the integrity of the inferior vestibular nerve thereby promising to be a useful tool in the audiological test battery to diagnose vestibular schwannoma. OBJECTIVE: To ascertain the utility of cVEMP in diagnosis of vestibular schwannoma in conjunction with the ABR and to evaluate whether the size of lesion has any effect on the cVEMP measures. METHODS: Case-files of 15 known cases of vestibular schwannoma whose pure tone audiometry, auditory brainstem response (ABR), cVEMP and radiological investigation findings were available, were included in the study. Patients were categorised as large or small tumours based on the size. The absolute and inter-peak latencies of ABR, amplitudes of waves V and I, and inter-aural latency difference of wave V of ABR; and latency of P1 and N1 of cVEMP and amplitude of P1-N1 complex were considered in the study. RESULTS: There were eight large and nine small tumours. All the patients with large tumours showed significant severity of hearing loss whereas only three out of nine patients with small tumours showed severe to profound deafness in the affected ear. The rest showed hearing status ranging from normal hearing sensitivity to moderate hearing loss. Most of the patients with large tumours showed complete absence of ABR in the affected ears with no identifiable wave-peaks. ABR in small tumours exhibited delayed III-I and delayed V-I interpeak latency interval (IPL). Four out of five patients with large unilateral tumours revealed contralateral effects of reduced amplitude or absence of cVEMP. On the contrary, six out of eight unilateral small tumours showed a normal cVEMP response in the contralateral ear. Both the patients with NF2 in the present study demonstrated cVEMP abnormalities. CONCLUSION: ABR and cVEMP, when used in combination, can be of immense use in identification of neuro-otologic conditions such as vestibular schwannoma and bilateral tumours in NF2. In the evaluation of unilateral vestibular schwannoma, abnormal contralateral findings of cVEMP and ABR are strongly indicative of the tumour size >2.5cm. In unilateral severe to profound loss wherein ABR in poorer ear cannot give information of site-of-lesion, cVEMP can help in the differentiation.

Swallowing characteristics in Amyotrophic Lateral Sclerosis.

BACKGROUND: Motor neurone disease also commonly known as Amyotrophic Lateral Sclerosis (ALS) is a neurological condition which affects various motor functions of the body. Dysphagia (disordered swallowing) is commonly seen in patients with ALS having bulbar symptoms. OBJECTIVES: Research reveals presence of dysphagia in patients with ALS at various stages of swallowing using instrumental assessment. However, very few studies have been done focussing on clinical profiling of swallowing in these patients. Hence, a need was felt to profile the specific characteristics. METHODOLOGY: Five patients diagnosed with ALS were assessed for presence of swallowing disorder using a swallowing checklist which focussed on assessing each stage of swallowing. RESULTS: Results revealed that patients with ALS exhibit difficulties in oral preparatory, oral and pharyngeal stages of swallowing. Inability to hold bolus, reduced mastication, residue in the oral cavity and nasal regurgitation while swallow were observed due to the affected oromotor functions. Swallow reflex was delayed in all the patients. Cough before and during swallow was also observed. CONCLUSION: Dysphagia is a common symptom in patients with ALS and occurs due to the affected oromotor functions. Specific information of the stages of swallowing helps in planning treatment in clinical practice.

Occurrence of communication and swallowing problems in neurological disorders: analysis of forty patients.

BACKGROUND: Communication and swallowing problems are common as a result of neurological conditions like stroke, traumatic brain injury, neoplasms of the nervous systems, viral encephalitis, diseases affecting neuromuscular junction and neuro degenerative conditions. The most frequently encountered problems are dysarthria, aphasia, dysphagia and apraxia of speech. OBJECTIVES: Although these disorders are mentioned in literature, very few studies describing the occurrence in different neurological conditions are available in Indian context. Hence, a need was felt to carry out such a study. METHODOLOGY: A heterogenous group of forty patients with neurological conditions were assessed for presence of speech, language and swallowing problems. A percent analysis was carried out to determine the occurrence of aphasia, dysarthria and dysphagia in general, in specific diseases and also to describe type of aphasia and dysarthria according to the characteristics presented. RESULTS: It was seen that the most frequently occurring disorder was dysarthria (60%), followed by dysphagia (55%) and aphasia (18%). It was also noted that dysarthria and dysphagia co-existed in around 45% patients with neurological diseases. CONCLUSIONS: It can be concluded that speech, language and swallowing problems are frequent in individuals with neurological conditions. Speech language pathologist plays an important role as a member of the rehabilitation team in a neurological setup with respect to identifying these problems and initiating intervention at the earliest. Hence, it is necessary for speech language pathologist to be well versed with the features each disorder may present with in terms of communication and swallowing.