Behavioral Site of Lesion Tests and Auditory System Redundancies

Flashcards covering behavioral site of lesion tests, intrinsic and extrinsic redundancies, definitions of central and peripheral auditory systems, and relevant historical sources from lecture slides.

Rollover Effect

A phenomenon caused by a lesion on the VIIIth nerve creating a bottleneck, where complex signals like speech presented at suprathreshold levels encounter neural congestion, disrupting speech discrimination and perception of continuous pure tones.

Intrinsic Redundancy

Internal redundancy of the central auditory nervous system arising from multiple neural pathways, auditory centres, decussations (contralateral crossovers), extensive interconnectivity, and bilateral representation (parallel processing) carrying sound signals from the cochlea to the auditory cortex.

Extrinsic Redundancy

External redundancy arising from features of the speech signal itself, including frequency cues, durational cues, contextual cues, rhythm, and familiarity with semantic, syntactic, and phonological rules of language.

Subtle Central Auditory Dysfunction Rule

The principle stating that the higher up the auditory pathway a disruption occurs, the more subtle the resulting central auditory dysfunction appears.

Cochlear / Retrocochlear (Peripheral Sensorineural) System

The portion of the auditory pathway bounded by the synapse of the VIIIth nerve at the cochlear nucleus (Kaplan et.al., 1984), encompassing any problem from the external auditory canal up to the synapse of the 8th nerve at the cochlea or nucleus.

Central Auditory System (Kaplan et.al., 1984)

The anatomical structures consisting of nuclei and transmission pathways in the lower and upper brainstem and the temporal lobe.

Four Parts of the Central Auditory System (Noffsinger & Kurdzeil, 1979)

The four structural divisions comprising: 1. Peripheral or extra-axial brainstem, 2. Central or intra-axial brainstem, 3. Ascending Auditory Pathways, and 4. Auditory Cortex of the temporal lobe and associated intrahemispheric associations.

Behavioral Site of Lesion Tests

Screening tools—not diagnostic tests—that possess poor sensitivity and specificity, including Loudness Balance, Short Increment Sensitivity Index (SISI), Tone Decay Tests, and Bekesy Audiometry, which have largely been supplanted by objective tests.

Monosyllabic PB Word Lists (Cerebral Lesions Response)

Speech testing materials that, along with pure tone thresholds, yield essentially normal results in patients with surgical lesions of the two cerebral hemispheres.

Short Increment Sensitivity Index (SISI)

A behavioral site of lesion test used as a screening tool characterized by poor sensitivity and specificity.

Tone Decay Tests

A category of behavioral site of lesion screening tests that have poor sensitivity and specificity and are largely supplanted by objective tests.

Bekesy Audiometry

A behavioral site of lesion screening test with poor sensitivity and specificity.

Loudness Balance

A behavioral site of lesion test used as a non-diagnostic screening tool in auditory system evaluation.