Correspondence: Lucio Tremolizzo, Neurology Unit, University of Milano-Bicocca, Via Cadore 48, 20900 Monza, Italy. Fax: 39 02 6448 8108. E-mail: lucio.tremolizzo@unimib.it (Received 4 October 2012; accepted 28 October 2012) Amyotrophic Lateral Sclerosis and Frontotemporal Degeneration, 2013; 14: 157–158 ISSN 2167-8421 print/ISSN 2167-9223 online © 2013 Informa Healthcare DOI: 10.3109/21678421.2012.746990 in Raaphorst’s one, we agree that motor impairment is a major determinant of this outcome, as did Raa- phorst (1). Interestingly, previous works have used the FAB without reporting problems; however, on closer inspection, ALS patients enrolled in these papers had milder disease, as documented by higher ALSFRS-R mean scores (e.g. Oskarsson et al., 2010, ALSFRS-R: 35.19  5.81, n  16 (2); Floris et al., 2012, ALS- FRS-R:  40 in 15 patients out of 20 (3); Ahn et al., 2011, ALSFRS-R: 38.4  3.5, n  61 (4); Morimoto et al., 2012, ALSFRS-R: 40.4  6.4 and 37.5  3.6, n  23 and 12 (5)). Most probably, the FAB is a fea- sible tool only during the first stages of ALS (3), and its value progressively diminishes with advancing motor impairment. This might be not the case of behavioural impairment that has been reported to be independent from motor impairment (6). In addition, also the sensitivity of the FAB as a screening tool seems not to be perfect, as suggested by the fact that in the Raphorst subgroup of eight ALS patients with a diagnosis of behavioural variant of frontal dementia, at least one had a FAB score of 18, i.e . at the top. In general, our data are, therefore, in agreement with those of Raaphorst et al. (1); raw FAB might return a low rate of completion and other tests less affected by motor performances might offer advan- tages. We decided to use WST just for further stress- ing this point, since this test can be administered with a minimum motor involvement, but the test alone may be hardly considered a suitable screening tool because it explores only a single executive function, i.e. sorting ability, as opposed to the FAB, which is a mini-battery. In conclusion, the need for dedicated tools for screening cognitive and behavioural dysfunctions in ALS patients is stronger than ever, especially when Dear Sir, We read with great interest the study by Raaphorst et al., reporting significant limitations of the frontal assessment battery (FAB) for cognitive impairment screening in amyotrophic lateral sclerosis (ALS) patients (1). The authors touch on an issue relevant to all ALS clinicians trying to assess frontal lobe impairment in their patients  the impossibility of achieving a full completion rate (lower than 80% in their series). The authors further explore this issue by proposing an item-adjusted FAB score seemingly demonstrating more reliability with respect to the raw score. However, the various items of the FAB tap different executive functions that may be vari- ably affected in each single ALS patient; thus, to pro-rate a FAB raw score due to missed items does not seem to be an optimal solution from a cognitive point of view. We performed a similar work in our ALS clinic assessing FAB and Weigl’s sorting test (WST) in 10 consecutive definite non-demented ALS patients (four bulbar/six spinal; mean ALSFRS-R: 25.8  6.7; age 67.4  10.9 years; median disease duration 25.5 months, first third quartiles 20.5 74, range 9 105). Incomplete testing was obtained at the FAB in 50% of our patients and the mean item completion rate was 85%. Bulbar patients could complete FAB in 75% of the cases, while spinal patients only in 33% (mostly due to the already reported relevant impact of the Luria item); by contrast, all patients could undergo the WST. Cohen’s kappa score between the item-adjusted FAB and WST was 0.44, which was not surprising since the two tests assess different functions within the frontal domain. Considering that the ALS- FRS-R score in our case series was even lower than LETTER TO THE EDITOR Exploring limits of neuropsychological screening in ALS: The FAB problem LUCIO TREMOLIZZO, CARLO FERRARESE & ILDEBRANDO APPOLLONIO ALS and Memory Clinics, Department of Neurology, San Gerardo Hospital and University of Milano-Bicocca, Italy