Study aims: The primary aim is to determine whether chewing efficiency, determined by a two-colour mixing ability test, and maximum bite and lip force decrease in ALS patients.

Study center: University Hospitals of Geneva Study type: Cohort study with matched controls Study population: 25 ALS patients included in the multidisciplinary cohort study of the University Hospital Geneva between October 2012 and October 2014 and followed for 3 years maximum and 25 controls, matched for age, sex and dental status.

Study duration: Inclusion from October 2012 to October 2016. Follow-up for 3 years.

Study hypothesis: Chewing efficiency, maximum bite and lip force decrease with time in ALS patients and may be a marker of texture adaptation and PEG necessity.

Study aims: The primary aim is to determine whether chewing efficiency, determined by a two-colour mixing ability test, and maximum bite and lip force decrease in ALS patients.

The secondary aims are to determine, in ALS patients, whether:

• Maximum bite and lip force decrease.
• Chewing efficiency, maximum bite and lip force decrease more in ALS patients with bulbar than with spinal onset.
• Chewing efficiency and bite force correlate with energy intakes, nasofibroscopic assessment, and a validated swallowing questionnaire.
• Saliva volume increases with time and progression of disease and influences masticatory efficiency.
• Saliva volume is associated with nasofibroscopy assessment.

Methods : Every three months, we will perform:

• As part of the ongoing cohort study (already accepted by the Ethical Committee) calculation of energy intakes through a 24h recall, nasofibroscopy, swallowing questionnaire and score of disease severity.
• As part of this study: assessment of dental status at first visit, chewing efficiency test by a with a colour mixing ability test, maximum voluntary bite and lip force, saliva volume and calculation of a 3-day dietary recall instead of a 24h recall.

Statistics: Evolutions with time and between groups, of chewing efficiency, bite and lip force will be assessed by repeated measures ANOVA. Correlations between two continuous variables will be examined by Spearman's correlation coefficients at the different time points. Correlations between a continuous variable and a binary variable (nasofibroscopic assessment) will be explored by logistic regression with mixed effect model.

Inclusion Criteria:

• ALS patients
• > 18 years
• Participation in the cohort study

Exclusion Criteria:

• Refusal of participating in the cohort study
• Presence of PEG

ALS patients participating in the cohort study of the University Hospital Geneva