Table 2.
Comparison of baseline characteristics between subtypes in all individuals with ALS–FTD spectrum disorder
| S1 n = 116 |
S2 n = 47 |
S0 n = 44 |
Missing data | PS1vsS2 | PS0vS1 | PS0vsS2 | |
|---|---|---|---|---|---|---|---|
| Age at MRI, years | 59.9 (9.7) | 63.0 (9.5) | 60.9 (9.2) | 0.0% | 0.07 | 0.59 | 0.27 |
| Sex, male% | 69 (59.5%) | 28 (59.6%) | 25 (56.8%) | 0.0% | 0.99 | 0.76 | 0.79 |
| Education, years | 16.8 (11.3) | 15.4 (2.7) | 15.1 (2.7) | 0.0% | 0.80 | 0.45 | 0.57 |
| Disease duration, monthsa | 29.0 (200.5) | 36.7 (200.8) | 28.4 (126.9) | 0.0% | 0.19 | 0.35 | 0.08 |
| Diagnostic delay, months | 29.1 (24.7) | 42.5 (41.8) | 19.1 (20.8) | 0.0% | 0.12 | 0.002 | 0.0004 |
| Clinical phenotypes | n = 116 | n = 47 | n = 44 | 0.0% | 0.06 | < 0.0001 | < 0.0001 |
| ALS | 48 (41.4%) | 14 (29.8%) | 41 (93.1%) | – | – | – | – |
| ALS–FTD | 26 (22.4%) | 19 (40.4%) | 2 (4.5%) | – | – | – | – |
| bvFTD | 42 (36.2%) | 14 (29.8%) | 1 (2.3%) | – | – | – | – |
| Symptom onset site | n = 110 | n = 45 | n = 44 | 3.9% | 0.17 | < 0.0001 | < 0.0001 |
| LMN | 45 (40.9%) | 16 (35.6%) | 31 (70.5%) | – | – | – | – |
| UMN | 14 (12.7%) | 2 (4.4%) | 11 (25.0%) | – | – | – | – |
| Cognitive | 51 (46.4%) | 27 (60.0%) | 2 (4.5%) | – | – | – | – |
| MMSE | 25.7 (4.5) | 24.3 (5.6) | 28.2 (2.2) | 6.3% | 0.40 | 0.0001 | 0.0008 |
| ECAS total | 91.0 (28.0) | 87.0 (30.2) | 113.9 (9.7) | 64.3% | 0.75 | 0.002 | 0.006 |
| ALS specific score | 66.8 (22.2) | 85.5 (8.3) | 85.5 (8.3) | – | 0.89 | 0.001 | 0.009 |
| ALS non-specific score | 24.2 (7.1) | 21.8 (7.8) | 28.4 (2.5) | – | 0.28 | < 0.05 | 0.005 |
| PBAC total | 67.3 (14.9) | 62.8 (19.1) | 81.5 (4.2) | 48.8% | 0.31 | < 0.0001 | 0.0002 |
| Executive scale | 8.0 (4.0) | 8.8 (3.5) | 12.7 (2.5) | – | 0.40 | < 0.0001 | 0.0001 |
| Language scale | 16.1 (3.3) | 14.2 (4.9) | 18.6 (0.6) | – | 0.10 | < 0.0001 | < 0.0001 |
| Visual scale | 15.3 (3.7) | 15.9 (3.9) | 17.6 (0.7) | – | 0.21 | 0.0002 | 0.05 |
| Memory scale | 13.0 (4.7) | 10.4 (6.2) | 14.6 (3.3) | – | 0.13 | 0.15 | 0.02 |
| Behavioral scale | 14.8 (4.0) | 13.5 (4.5) | 18.0 (0.0) | – | 0.15 | < 0.0001 | < 0.0001 |
| BNT | 24.8 (4.7) | 17.3 (8.0) | 27.6 (1.9) | 37.2% | < 0.0001 | 0.007 | < 0.0001 |
| Animal fluency task | 13.1 (6.6) | 10.4 (7.1) | 19.9 (5.6) | 27.5% | 0.06 | < 0.0001 | < 0.0001 |
| Letter fluency task | 8.9 (5.3) | 8.0 (5.0) | 13.1 (4.5) | 6.8% | 0.42 | < 0.0001 | < 0.0001 |
| Digit forward span | 6.1 (1.4) | 6.1 (1.2) | 7.1 (1.2) | 14.0% | 0.77 | 0.0002 | 0.0003 |
| Digit backward span | 3.9 (1.7) | 3.9 (1.6) | 4.8 (1.2) | 14.5% | 0.86 | 0.001 | 0.009 |
| Genetic pathogenic variantsb | n = 112 | n = 45 | n = 23 | 27.1% | – | – | – |
| C9orf72 | 37 (33.0%) | 10 (22.2%) | 1 (4.4%) | – | 0.18 | 0.004 | 0.06 |
| GRN | 11 (9.8%) | 0 (0.0%) | 0 (0.0%) | – | 0.03 | 0.21 | 1.00 |
| MME | 0 (0.0%) | 0 (0.0%) | 1 (4.4%) | – | 1.00 | 0.17 | 0.34 |
| TBK1 | 0 (0.0%) | 2 (4.4%) | 0 (0.0%) | – | 0.08 | 1.00 | 0.55 |
| TARDBP | 0 (0.0%) | 2 (4.4%) | 0 (0.0%) | – | 0.08 | 1.00 | 0.55 |
| FTLD/ALS-TDPc | n = 29 | n = 15 | n = 11 | 73.4% | 0.002 | 0.0009 | < 0.0001 |
| Type A | 13 (44.8%) | 3 (20.0%) | 0 (0.0%) | – | – | – | – |
| Type B/E | 8 (27.6%) | 9 (60.0%) | 1 (9.1%) | – | – | – | – |
| Type C | 0 (0.0%) | 3 (20.0%) | 0 (0.0%) | – | – | – | – |
| Non-specific | 8 (27.6%) | 0 (0.0%) | 10 (90.9%) | – | – | – | – |
| SuStaIn stage | 9.8 (8.1) | 12.2 (7.8) | 0 (0.0) | 0.0% | < 0.05 | – | – |
Bold values indicate statistically significant results
Data are presented as mean (standard deviation) for the continuous variables, and as number (frequency) for the categorical variables. Missing data indicate the percentage of individuals with missing data
S0 Normal-appearing group, S1 Prefrontal/Somatomotor-predominant subtype, S2 Limbic-predominant subtype, ALS amyotrophic lateral sclerosis, ALS–FTD amyotrophic lateral sclerosis-frontotemporal degeneration, bvFTD behavioral variant frontotemporal degeneration, LMN lower motor neuron, UMN upper motor neuron, MMSE Mini-Mental Status Examination, ECAS Edinburgh Cognitive Assessment Scale, PBAC Philadelphia Brief Assessment of Cognition, BNT Boston naming test, FTLD/ALS-TDP frontotemporal lobar degeneration or amyotrophic lateral sclerosis with TDP-43 inclusions, SuStaIn Subtype and Stage Inference
aData presented as median (range)
bNumber of individuals for genetic screening
cNumber of individuals receiving neuropathological examination