Segmental timing in amyotrophic lateral sclerosis

Area of Science:

• Speech Science
• Neurology
• Linguistics

Background:

• Amyotrophic Lateral Sclerosis (ALS) is a progressive neurodegenerative disease affecting motor neurons.
• Speech impairments, including altered timing, are common in ALS patients.
• Understanding segmental timing is crucial for assessing speech intelligibility deficits.

Purpose of the Study:

• To investigate segmental timing patterns in speakers with ALS.
• To compare ALS speakers' timing with neurologically healthy speakers at habitual and slow rates.
• To determine if segmental timing contributes to intelligibility deficits in ALS.

Main Methods:

• Comparison of segment durations between ALS speakers and matched controls.
• Analysis of temporal differences for specific sound classes (vowels, fricatives, stop gaps).
• Examination of prepausal lengthening in vowels.

Main Results:

• ALS speakers exhibited slowed articulatory rates affecting segmental timing.
• Segmental timing in ALS broadly aligned with voluntarily slowed speech in controls.
• Temporal differences for sound classes and prepausal lengthening were largely similar across groups.

Conclusions:

• The slowed rate in ALS influences segmental timing but may not be the primary cause of intelligibility issues.
• Segmental timing patterns in ALS resemble those of healthy individuals speaking slowly.
• Temporal cues like vowel duration may not be reliable for listeners to perceive speech deficits in ALS.