Motor symptoms in genetic frontotemporal dementia: developing a new module for clinical rating scales
Authors: Samra Kiran , MacDougall Amy M. , Peakman Georgia , Bouzigues Arabella , Bocchetta Martina , Cash David M. , Greaves Caroline V. , Convery Rhian S. , van Swieten John C. , Jiskoot Lize , Seelaar Harro , Moreno Fermin , Sanchez-Valle Raquel , Laforce Robert , Graff Caroline , Masellis Mario , Tartaglia Carmela , Rowe James B. , Borroni Barbara , Finger Elizabeth , Synofzik Matthis , Galimberti Daniela , Vandenberghe Rik , de Mendonça Alexandre , Butler Chris R. , Gerhard Alexander , Ducharme Simon , Le Ber Isabelle , Tiraboschi Pietro , Santana Isabel , Pasquier Florence , Levin Johannes , Otto Markus , Sorbi Sandro , Rohrer Jonathan D. , Russell Lucy L. ,   the Genetic FTD Initiative (GENFI), Nelson Annabel , Bocchetta Martina , Cash David , Thomas David L. , Todd Emily , Benotmane Hanya , Nicholas Jennifer , Samra Kiran , Shafei Rachelle , Timberlake Carolyn , Cope Thomas , Rittman Timothy , Benussi Alberto , Premi Enrico , Gasparotti Roberto , Archetti Silvana , Gazzina Stefano , Cantoni Valentina , Arighi Andrea , Fenoglio Chiara , Fumagalli Giorgio , Borracci Vittoria , Rossi Giacomina , Giaccone Giorgio , Di Fede Giuseppe , Caroppo Paola , Tiraboschi Pietro , Prioni Sara , Redaelli Veronica , Tang-Wai David , Rogaeva Ekaterina , Castelo-Branco Miguel , Freedman Morris , Keren Ron , Black Sandra , Mitchell Sara , Shoesmith Christen , Bartha Robart , Rademakers Rosa , Poos Jackie , Papma Janne M. , Giannini Lucia , van Minkelen Rick , Pijnenburg Yolande , Nacmias Benedetta , Ferrari Camilla , Polito Cristina , Lombardi Gemma , Bessi Valentina , Veldsman Michele , Andersson Christin , Thonberg Hakan , Öijerstedt Linn , Jelic Vesna , Thompson Paul , Langheinrich Tobias , Lladó Albert , Antonell Anna , Olives Jaume , Balasa Mircea , Bargalló Nuria , Borrego-Ecija Sergi , Verdelho Ana , Maruta Carolina , Ferreira Catarina B. , Miltenberger Gabriel , do Couto Frederico Simões , Gabilondo Alazne , Gorostidi Ana , Villanua Jorge , Cañada Marta , Tainta Mikel , Zulaica Miren , Barandiaran Myriam , Alves Patricia , Bender Benjamin , Wilke Carlo , Graf Lisa , Vogels Annick , Vandenbulcke Mathieu , Van Damme Philip , Bruffaerts Rose , Poesen Koen , Rosa-Neto Pedro , Gauthier Serge , Camuzat Agnès , Brice Alexis , Bertrand Anne , Funkiewiez Aurélie , Rinaldi Daisy , Saracino Dario , Colliot Olivier , Sayah Sabrina , Prix Catharina , Wlasich Elisabeth , Wagemann Olivia , Loosli Sandra , Schönecker Sonja , Hoegen Tobias , Lombardi Jolina , Anderl-Straub Sarah , Rollin Adeline , Kuchcinski Gregory , Bertoux Maxime , Lebouvier Thibaud , Deramecourt Vincent , Santiago Beatriz , Duro Diana , Leitão Maria João , Almeida Maria Rosario , Tábuas-Pereira Miguel , Afonso Sónia 
Published: November 2022

Abstract
Objective
To investigate the optimal method of adding motor features to a clinical rating scale for frontotemporal dementia (FTD).

Methods
Eight hundred and thirty-two participants from the international multicentre Genetic FTD Initiative (GENFI) study were recruited: 522 mutation carriers (with C9orf72, GRN and MAPT mutations) and 310 mutation-negative controls. A standardised clinical questionnaire was used to assess eight motor symptoms (dysarthria, dysphagia, tremor, slowness, weakness, gait disorder, falls and functional difficulties using hands). Frequency and severity of each motor symptom was assessed, and a principal component analysis (PCA) was performed to identify how the different motor symptoms loaded together. Finally, addition of a motor component to the CDR® plus NACC FTLD was investigated (CDR® plus NACC FTLD-M).

Results
24.3% of mutation carriers had motor symptoms (31.7% C9orf72, 18.8% GRN, 19.3% MAPT) compared to 6.8% of controls. Slowness and gait disorder were the commonest in all genetic groups while tremor and falls were the least frequent. Symptom severity scores were similar to equivalent physical motor examination scores. PCA revealed that all motor symptoms loaded together so a single additional motor component was added to the CDR® plus NACC FTLD to form the CDR® plus NACC FTLD-M. Individual global scores were more severe with the CDR® plus NACC FTLD-M, and no patients with a clinically diagnosed motor disorder (ALS/FTD-ALS or parkinsonism) were classified anymore as asymptomatic (unlike the CDR® plus NACC FTLD alone).

Conclusions
Motor features are present in mutation carriers at all disease stages across all three genetic groups. Inclusion of motor symptoms in a rating scale that can be used in future clinical trials will not only ensure a more accurate severity measure is recorded but that a wider spectrum of FTD phenotypes can be included in the same trial.