Clinical aspects of cortical deafness

Speech perception abilities for spectrally modified signals in individuals with auditory dys-synchrony

OBJECTIVE

The objective of the study was to determine the speech perception abilities for spectrally modified speech signals in individuals with auditory dys-synchrony.

STUDY SAMPLE

The speech identification scores of 30 normal hearing and 12 individuals diagnosed as having auditory dys-synchrony were studied.

DESIGN

Phonemically balanced words in Kannada developed by Yathiraj and Vijayalakshmi (2005) were presented unfiltered and filtered at 1700 Hz low-pass and 1700 Hz high-pass cut-off frequencies, and speech identification performance was assessed.

RESULTS

Results revealed that there is a highly significant difference in speech identification scores for unfiltered and low-pass filtered words. This difference could be attributed to the physiological coding deficits of low frequency information which are usually coded by phase locked responses in auditory nerve fibers ( Sek & Moore, 1995 ).

CONCLUSIONS

Thus, low-pass filtered words can be used as an effective tool to identify individuals with auditory dys-synchrony, especially those who have good speech identification scores in quiet.

Auditory processing assessment in older people with no report of hearing disability

In the elderly, the results of central auditory pathways behavioral assessments are considered to be difficult to read because of the possible interference of peripheral auditory pathway involvement. Aim: Assess the efficacy of the central auditory function in elderly patients who do not complain of hearing. Materials and Methods: Case study involving 40 individuals within the age range of 60 to 75 years. The patients underwent auditory processing evaluation based on anamnesis, otorhinolaryngological exam, threshold tonal audiometry, speech recognition threshold, speech recognition index, immittance measures, stapes reflex study, synthetic phrases identification test with ipsilateral competitive message, frequency pattern test and alternate twin-syllable test through dichotic task; age range and hearing loss influenced results from the phrases identification with ipsilateral competitive message. Percentages of right answers below normal standards were seen in the three tests that assessed the central auditory functions. Conclusion: Elderly individuals who did not complain of hearing presented relevant prevalence of signs of central auditory function inefficiencies.

Avaliação do processamento auditivo em idosos que relatam ouvir bem

Em idosos, os resultados da avaliação comportamental das vias auditivas centrais são considerados de difícil interpretação devido à possível interferência do comprometimento das vias auditivas periféricas. OBJETIVO: Avaliar a eficiência das funções auditivas centrais de idosos que relatam ouvir bem. MATERIAL E MÉTODO: Estudo de casos que incluiu 40 indivíduos na faixa etária de 60 a 75 anos. Os pacientes foram submetidos à avaliação do processamento auditivo que constou de anamnese, exame otorrinolaringológico, audiometria tonal liminar, limiar de reconhecimento de fala, índice de reconhecimento de fala, imitanciometria, pesquisa de reflexos estapedianos, teste de identificação de sentenças sintéticas com mensagem competitiva ipsilateral, teste de padrões de freqüência e teste de dissílabos alternados por meio de tarefa dicótica. RESULTADOS: Gênero, faixa etária e perda auditiva não influenciaram os resultados dos testes de padrões de freqüência e dissílabos alternados por meio de tarefa dicótica; faixa etária e perda auditiva influenciaram os resultados do teste de identificação de sentenças com mensagem competitiva ipsilateral. Porcentagens de acertos abaixo dos padrões da normalidade de adultos foram observadas nos três testes que acessam as funções auditivas centrais. CONCLUSÃO: Indivíduos idosos que relatam ouvir bem apresentam prevalência relevante de sinais de ineficiência das funções auditivas centrais.

Modality Specificity as a Criterion for Diagnosing Central Auditory Processing Disorders

A central "auditory" processing disorder (CAPD) is an auditory perceptual dysfunction that cannot be explained on the basis of peripheral hearing loss. As a concept, CAPD has not been completely validated, and many issues continue to be controversial. A primary issue of concern is whether currently used tests to evaluate CAPD are sensitive to factors that are not of an auditory perceptual nature. In this paper, we consider the case for modality specificity as a criterion for improving the specificity of diagnosing CAPD. Demonstrating the modality-specific nature of sensory processing deficits is one way to rule out nonperceptual factors as explanations for observed dysfunction.

Clinical application of distorted speech audiometry

The clinical validity of four different low-redundant speech tests was calculated using four groups of 83 patients with retrocochlear or central auditory lesions. The speech tests used were: interrupted speech (7 or 10 interruptions/s) time-compressed speech and filtered speech. A comparison between patients and age-matched normal-hearing controls showed that the patients had significantly lower speech recognition score. The best sensitivity ratings of the tests were between 47% and 80%, the highest in patients with cerebellopontine angle tumours and temporal lobe lesions, and the lowest in vascular brainstem lesions. The speech tests with the highest sensitivity were 7 interruptions/s and time-compressed speech.

Speech audiometric trial using synthetic vowels produced with DEC-talk

A speech audiometric trial is described for testing the degree of hearing loss and its pathogenesis. Test vowels and distorted speech sounds were synthesized with DECtalk for use in speech audiometric tests. Results showed that 100% articulation can be obtained with undistorted synthesized vowels, while reasonable articulation scores can be obtained with distorted synthetic speech signals. This method could solve some of the problems inherent in use of recorded natural Japanese speech sounds as acoustic stimuli during otological examinations.

Perception of time-altered monosyllables in a specific group of phonologically disordered children

Temporal auditory processing of open (e.g. pie) versus closed (e.g. pipe) syllables in a specific group of phonologically impaired children who deleted word-final consonants and normal phonologically developing children between the ages of 4 and 7 yr was investigated. The disordered group demonstrated significantly poorer discrimination at the faster but not slower rates of speech. Imitation of word-final consonants did not significantly increase in the disordered subjects when presented with time-expanded speech although certain individuals made noticeable improvements. Discussion of temporal auditory processing deficits from a neuropsychological perspective which suggests different etiologies is offered.