Hand gestures and speech impairments in spoken and sung modalities in people with Alzheimer's disease

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In Alzheimer’s disease (AD), studies on language productiondo not treat aspects of speech and hand gestures in aconcomitant way. However, many studies describe eitherapraxia of speech, or orofacial apraxia, or upper limb apraxia,or aphasia. This paper reports an original protocol exploitingspeech, singing and hand gestures to evaluate the correlationbetween upper limb and speech apraxia in spoken and sungmodalities in 4 AD patients paired with 4 control participants.We did not evidence any speech apraxia in our AD patientpopulation, unlike upper limb apraxia. However significantdifferences were observed on productions of hand gestures andspeech between the patients and the control participants.Regarding patients, the movement, configuration andorientation of hand gestures were slightly altered. The handgestures alteration seemed to depend on their value but not onthe spoken vs. sung modality. The simultaneous repetition ofconnected hand gestures affected also both vocal and speechproductions. More specifically, hand gestures seemed to impactthe production of speech. The modality (spoken vs. sung) alsoseemed to influence speech productions at different degrees:patients made more errors in singing, and the more withconnected hand gestures showing a double task effect.