Table 1.

Clinical details of phFTD and bvFTD patients included in the analyses. Described are the behavioral and cognitive profiles of phFTD patient at the time of inclusion, and those of bvFTD patients at the time of diagnosis. Also listed are basis of diagnosis, number of visits and follow up, and (decline) of functional status as assessed by asking patients and/or their caregivers about the patient's ability to perform (instrumental) activities of daily living (as detailed in the Methods).

Behavioral and cognitive profile		Diagnosis based on	Follow up	Functional status
phFTD patients
1	Behavioral symptoms:  Behavioral disinhibition, loss of empathy	No progression for 4 years	Clinical  5 visits  5 year FU Neuropsychological  4 visits  4 year FU	Stable as reported by both patient and caregiver.
Neuropsychological evaluation per domain (3rd visit):  Orientation to person, time, place: unimpaired  Memory: average  Language: below average to average  Attention: average to poor  Executive functions: average to poor  Information processing speed: below average  Visuoconstructive ability: unimpaired  Social cognition: poor  Conclusion: although the impairments listed above are suspect for FTD, the absence of evident cognitive decline and the long disease course render this diagnosis less likely.
2	Behavioral symptoms:  Behavioral disinhibition, apathy, compulsive behavior, hyperorality	No progression for 9 years	Clinical  9 visits  9 years Neuropsychological  3 visits  8.8 years	Stable as reported by both patient and caregiver.
Neuropsychological evaluation per domain (3rd visit):  Orientation to person, time, place: unimpaired  Memory: unimpaired  Language: average to poor  Attention: average to poor  Executive functions: average to below average  Information processing speed: below average  Visuoconstructive ability: unimpaired  Social cognition: poor  Conclusion: although the impairments listed above and the clinical presentation are suspect for FTD, the patient's intact insight into his/her own functioning, the absence of any evident cognitive decline and the very long disease course render this diagnosis less likely.
3	Behavioral symptoms:  Behavioral disinhibition, loss of empathy, loss of insight	No progression for 1 year	Clinical  3 visits  1 year Neuropsychological  2 visits  1 year	Stable as reported by both patient and caregiver.
Neuropsychological evaluation per domain (2nd visit):  Orientation to person, time, place: unimpaired  Memory: highly variable (unimpaired to poor)  Language: average to poor  Attention: below average to poor  Executive functions: average to poor  Information processing speed: average  Visuoconstructive ability: unimpaired  Social cognition: poor  Conclusion: compared to the previous neuropsychological evaluation there is no evident cognitive decline.
4	Behavioral symptoms:  Behavioral disinhibition, loss of insight	No progression for 5 years	Clinical  5 visits  5 year Neuropsychological  3 visits  4.8 years	Patient reports minor difficulties at work, but performs activities of daily living independently and has no difficulties operating appliances according to caregiver.
Neuropsychological evaluation per domain (3rd visit):  Orientation to person and place: unimpaired; to time: sufficient  Memory: unimpaired to below average  Language: below to above average  Attention: average to poor  Executive functions: below average to poor  Information processing speed: average to below average  Visuoconstructive ability: unimpaired  Social cognition: average  Conclusion: although the impairments listed above and the clinical presentation as well as the cognitive decline reported by patient and caregiver are suspect for FTD, the absence of evident cognitive decline renders this diagnosis less likely.
5	Behavioral symptoms:  Behavioral disinhibition, apathy, loss of empathy	No progression for 6 years	Clinical  9 visits  6 years Neuropsychological  5 visits  5.9 years	Minor difficulties reported by patient at first and second visits which had stabilized or improved at later visits, e.g. disorientation while driving, but not anymore when driving using GPS navigation, confirmed by caregiver.
Neuropsychological evaluation per domain (5th visit):  Orientation to person, time, place: unimpaired  Memory: average  Language: average  Attention: average to above average  Executive functions: above average  Information processing speed: above average  Visuoconstructive ability: unimpaired  Social cognition: below average  Conclusion: the results are similar to previous neuropsychological examinations. There are no indications for cognitive impairment.
6	Behavioral symptoms:  Behavioral disinhibition, apathy, loss of empathy	No progression for 1.2 years (slight functional decline but no clinical or cognitive deterioration).	Clinical  5 visits  1.2 years Neuropsychological  2 visits  1.2 years	Very slow progression but performs activities of daily living independently according to caregiver.
Neuropsychological evaluation per domain (2nd visit):  Orientation to person, time, place: unimpaired  Memory: average to poor  Language: average  Attention: below to above average  Executive functions: average to poor  Information processing speed: average  Visuoconstructive ability: unimpaired  Social cognition: below average  Conclusion: although the impairments listed above and the clinical presentation are suspect for FTD, the patient's intact insight into his/her own functioning and the absence of any cognitive decline render this diagnosis less likely.
7	Behavioral symptoms:  Behavioral disinhibition, apathy, loss of empathy, hyperorality	No progression for 10 years	Clinical  9 visits  10.1 years Neuropsychological  4 visits  9.7 years	Activities of daily living are scarcely performed due to the patient's severe apathy according to caregiver.
Neuropsychological evaluation per domain (4th visit):  Orientation to person, time, place: unimpaired  Memory: average to poor  Language: average to poor  Attention: below average to poor  Executive functions: average to poor  Information processing speed: average  Visuoconstructive ability: unimpaired  Social cognition: poor  Conclusion: although the impairments listed above and the clinical presentation as well as the cognitive decline reported by the caregiver are suspect for FTD, the absence of evident cognitive decline renders this diagnosis less likely.
bvFTD patients
1	Behavioral symptoms:  Behavioral disinhibition, loss of empathy	Clinical presentation as well as functional and cognitive decline	Clinical  2 visits  1 year Neuropsychological evaluation  2 visits  1 years	Functional decline reported by caregiver of several (instrumental) activities of daily living.
Neuropsychological evaluation per domain (2nd visit):  Orientation to person and place: unimpaired; to time: impaired  Memory: average to poor  Language: below average  Attention: poor  Executive functions: average to poor  Information processing speed: average  Visuoconstructive ability: poor  Conclusion: although previous neuropsychological evaluation did not provide any indication for a neurodegenerative disorder, the newly reported information by patient and caregiver and the cognitive decline substantiated by the current evaluation support the diagnosis of FTD.
2	Behavioral symptoms:  Apathy, loss of empathy	Clinical presentation as well as functional and cognitive decline	Clinical  3 visits  1.8 years Neuropsychological evaluation  2 visits  1.3 years	Functional decline reported by patient and caregiver of several (instrumental) activities of daily living.
Neuropsychological evaluation per domain (2nd visit):  Orientation to person, time, place: unimpaired  Memory: above average to average  Language: unimpaired to below average  Attention: average to poor  Executive functions: average to below average  Information processing speed: below average  Visuoconstructive ability: below average  Conclusion: compared to the previous neuropsychological evaluation, memory remained intact, but there is cognitive decline specifically in the domains of attention and executive functioning, indicative of a dementia syndrome, most likely FTD.
3	Behavioral symptoms:  Behavioral disinhibition, apathy, loss of empathy, loss of insight, hyperorality	Clinical presentation, functional decline and cognitive impairment	Clinical  3 visits  2 months Neuropsychological evaluation  1 visit	Functional decline reported by caregiver of several (instrumental) activities of daily living.
Neuropsychological evaluation per domain (1st visit):  Orientation to person and time: unimpaired; to place: impaired  Memory: below average to poor  Language: poor  Attention: average to poor  Executive functions: poor  Visuoconstructive ability: average  Conclusion: the cognitive profile is indicative of dementia, clinically presenting as FTD.
4	Behavioral symptoms:  Apathy, loss of empathy, compulsive behavior	Clinical presentation as well as and functional and cognitive decline	Clinical  3 visits  1.3 years Neuropsychological evaluation  2 visits  1.3 years	Progressive functional decline as reported by caregiver.
Neuropsychological evaluation per domain (2nd visit):  Orientation to person, time, place: unimpaired  Memory: poor  Language: below average to poor  Attention: average to poor  Executive functions: unimpaired  Visuoconstructive ability: unimpaired  Information processing speed: below average  Conclusion: the decline in the cognitive domains of langue, attention and information processing speed compared to the previous neuropsychological evaluation, as well as the current overall cognitive profile and clinical presentation are indicative of FTD.
5	Behavioral symptoms:  Apathy, loss of insight, stereotyped and compulsive behavior, hyperorality	Clinical presentation as well as functional and cognitive decline	Clinical  4 visits  2 years Neuropsychological evaluation  2 visits  1.3 years	Progressive functional decline as reported by caregiver, eventual admission to nursing home.
Neuropsychological evaluation per domain (2nd visit):  Orientation to person,: unimpaired; to time and place: impaired  Memory: average to poor  Language: average to poor  Attention: below average to poor  Executive functions: poor Information processing speed: average  Visuoconstructive ability: poor (due to executive dysfunction)  Conclusion: the cognitive decline in domains of attention and executive functioning and impairment on other domains, combined with the clinical presentation fit the profile of bvFTD.
6	Behavioral symptoms:  Behavioral disinhibition, compulsive behavior, hyperorality	Clinical presentation as well as functional and cognitive impairment.	Clinical  6 visits  2.4 years Neuropsychological evaluation  1 visit	Minor difficulties with operating appliances, grocery shopping, and laundry, as reported by caregiver.
Neuropsychological evaluation per domain (1st visit):  Orientation to person, time, place: unimpaired  Memory: unimpaired  Language: below average to poor  Attention: below average  Executive functions: below average  Visuoconstructive ability: unimpaired  Conclusion: the mildly impaired attention and executive functions, combined with impaired language and intact memory and praxis, may be indicative of FTD
7	Behavioral symptoms:  Behavioral disinhibition, loss of empathy, compulsive behavior	Clinical presentation, functional decline and cognitive impairment. C9ORF72 mutation present.	Clinical  5 visits  1.5 years Neuropsychological evaluation  1 visit	Progressive functional decline as reported by caregiver, eventual admission to day care (5 days a week).
Neuropsychological evaluation per domain (1st visit):  Orientation to person, time, place: unimpaired  Memory: poor  Language: below average to poor  Attention: average to poor  Executive functions: average  Visuoconstructive ability: average  Conclusion: the focal impairment in the language domain could possibly be attributed to logopenic progressive aphasia (LPA) but the absence of memory impairment and the prominent behavioral symptoms are not typical for LPA.
8	Behavioral symptoms:  Behavioral disinhibition, loss of empathy, loss of insight, stereotyped and compulsive behavior	Screened for MAPT mutation before the onset of symptoms because of positive family history. Clinical conversion to FTD confirmed 1.3 years later (based on clinical presentation, cognitive and functional decline).	Clinical  5 visits  1.3 year Neuropsychological evaluation  2 visits  1.4 year	Functional decline reported initially by patient and later by caregiver of several (instrumental) activities of daily living.
Neuropsychological evaluation per domain (2nd visit):  Orientation to person, time, place: unimpaired  Memory: average to below average  Language: below average to poor  Attention: unimpaired  Executive functions: unimpaired to below average  Information processing speed: unimpaired  Visuoconstructive ability: unimpaired  Social cognition: poor  Conclusion: the cognitive profile of impairment in language, memory and social cognition, combined with the cognitive decline compared to the previous neuropsychological evaluation and clinical presentation, are compatible with (conversion to) bvFTD.
9	Behavioral symptoms:  Behavioral disinhibition, apathy, loss of empathy, compulsive behavior	Clinical presentation as well as functional and cognitive decline.	Clinical  2 visits  1 week Neuropsychological  1 visit.  Test results of neuropsychological evaluation conducted 6 months earlier elsewhere were also available.	Functional decline of several (instrumental) activities of daily living decline reported by caregiver.
Neuropsychological evaluation per domain (1st visit, compared to neuropsychological exam performed elsewhere):  Orientation to person and place: unimpaired; to time: sufficient  Memory: highly variable (unimpaired to poor) average  Language: highly variable (unimpaired to poor)  Attention: unimpaired  Executive functions: average to poor  Information processing speed: below average  Visuoconstructive ability: unimpaired  Social cognition: poor  Conclusion: the cognitive profile of impairment in language, memory and social cognition, combined with the cognitive decline compared to the previous neuropsychological evaluation [conducted elsewhere] and clinical presentation, are compatible with bvFTD.
10	Behavioral symptoms:  Loss of empathy, loss of insight	Clinical presentation, cognitive impairment and functional decline.	Clinical  4 visits  0.8 year Neuropsychological  Test results of neuropsychological evaluation conducted earlier elsewhere were available.	Performs activities of daily living independently but has progressive difficulties operating appliances and managing finances, as reported by caregiver.
Neuropsychological exam conducted elsewhere showed poor performance on multiple domains, particularly executive functioning and language
11	Behavioral symptoms:  Apathy, loss of empathy	Screened for MAPT mutation when symptoms first manifested because of positive family history. Diagnosis based on mutation, clinical presentation, cognitive and functional decline.	Clinical  2 visits  1 month Neuropsychological  Test results of two neuropsychological evaluations with 1.2 year interval conducted elsewhere were available.	Increasing interference with daily functioning, as reported by caregiver.
Neuropsychological evaluation per domain (2nd neuropsychological exam performed elsewhere):  Orientation to person and place: unimpaired; to time: impaired  Memory: poor  Language: highly variable (unimpaired to poor)  Attention: unimpaired  Executive functions: below average to poor  Information processing speed: below average  Visuoconstructive ability: unimpaired  Social cognition: poor  Conclusion: compared to the previous evaluation there is a decline in orientation and language