Deactivating electrodes improves consonant but worsens vowel perception in ACE users

Evidence

Garadat et al. ( 2013 ) deactivated electrodes based on modulation detection in a group of ACE users. Up to five electrodes were switched off and they were selected such that only individual non-adjacent contacts were deactivated to avoid large regions being switched off. Following deactivation they demonstrated significant benefit for consonant perception and CUNY sentences in speech-shaped noise (8 out of 12 showed benefit) but demonstrated a deterioration in performance for vowel perception (7 out of 12 showed degradation). Testing was acute so learning effects were not controlled for and listeners were not given time to adapt to the experimental maps; with further experience and acclimatisation users may have performed better on the vowel task, particularly because it is known that vowel perception is sensitive to filtering adjustments (Friesen et al. 1999 ). — Dijk, Pim van, Physiology, Psychoacoustics and…, 2058

Categorization

• QUESTION: Why would deactivation benefit consonants while degrading vowels? The vowel-degradation mechanism tied to filtering adjustments and acclimatization warrants chasing.
• corroborated: 3 independent passages support this claim — Dijk, Pim van, Physiology, Psychoacoustics and…, 2058
• XREF: connects to: Pitch-based electrode deactivation provides no speech benefit for ACE users — Dijk, Pim van, Physiology, Psychoacoustics and…, 2050; Deactivating CI electrodes worsens spectral resolution rather than improving speech perception; Deactivating electrodes can shift frequency-to-electrode mapping and worsen perception (+2 more)

Broader Connections

• Deactivating CI electrodes worsens spectral resolution rather than improving speech perception #contradicts (0.90)
• Deactivating electrodes can shift frequency-to-electrode mapping and worsen perception #expands (0.78)
• Cochlear device users benefit less from electrode deactivation than AB and MEDEL users #contradicts (0.75) — Dijk, Pim van, Physiology, Psychoacoustics and…, 2051
• Electrode deactivation outcomes depend on stimulation rate and filter allocation differences #qualifies (0.75)