Swallowing disorders in dementia

The enormous efforts devoted towards finding the cause and cure for dementia have so far failed, with clinical trials being unsuccessful in improving or reducing the progressive worsening of cognitive impairment. To counter these failures, greater emphasis has been placed on establishing an early diagnosis; recognising pre-symptomatic and pre-clinical phases, to ultimately allow for the earlier introduction of therapies aimed at preventing or delaying dementia.

Aims

1. Characterise the neural mechanisms underlying this swallowing disorder in Tau-P301L mice; and
2. Determine the severity of tauopathy and neurodegeneration in key areas critically involved in coordinating swallowing and breathing. These include:
- Nucleus of the solitary tract, which generates a phasic or rhythmic ‘command’ to produce sequential swallowing in response to sensory stimuli;
- Nucleus ambiguus, which contains the laryngeal motoneurons innervating the vocal folds; and
- Kölliker-Fuse nucleus, which provides tonic drive for the laryngeal adductors and completely seals the trachea during, and between, swallows.

Research in our laboratory focuses on identifying symptoms of dementia that precede the onset of cognitive deficits. In an animal model of frontotemporal dementia caused by a P301L mutation in protein tau, we have detected swallowing deficits and irregular coordination between swallowing and breathing, which are common complications that accompany dementia, but may also be an early symptom.