The clinical features of SCA2 in 111 patients from 32 families have recently been tabulated,21 with a reported frequency of "mental deterioration" of 14%, including 4% who displayed only "memory loss." This was in contrast to the findings in the original Cuban pedigree, where "dementia" occurred in only 1 of 263 affected pedigree members.26 Subsequent reports of other pedigrees between 1993 and 1995, comprising 98 patients in total, failed to mention cognitive impairment or dementia as a feature of SCA2.7,23- 25,28 Dürr et al27 reported 3 SCA2 pedigrees from Martinique, with dementia occurring in only 1 of these families. Geschwind et al22 noted dementia in 6 of their 16 American patients with SCA2, apparently all from the same early-onset African American pedigree. The nature of the dementia was not specified in the report but consisted of a history indicative of frontal-subcortical dementia, progressing rapidly to global dementia that had supervened in each case before assessment could be undertaken (Dan Geschwind, MD, PhD, written communication, March 1998). Schöls et al20 recently reported that "mild dementia was suspected clinically in 5 [of 21 SCA2] patients," with "poor memory, concentration problems, deficits in cognitive function, and emotional instability." Cancel et al21 related "memory loss or dementia" in patients with SCA2 to duration of illness; those without such impairment had a mean disease duration of 10.8±7.0 years, whereas those with these features had a mean disease duration of 17.3±9.0 years.21 There was no correlation with CAG repeat length, and no mention was made of a correlation with ataxia severity, which is likely to depend on both CAG repeat length and duration of illness. Kish et al35 had previously reported that the degree of cognitive impairment correlated with ataxia severity in a heterogeneous group of patients with SCA.35 Interestingly, this impairment involved executive control, with more generalized cognitive dysfunction appearing in addition in some of the most severely affected patients. This suggestion of frontal-executive dysfunction in the SCAs has been confirmed for SCA3 (Machado-Joseph disease) by means of a different battery of neuropsychological tests, in a detailed study of 6 patients from 1 pedigree.13 The authors concluded that specific cognitive deficits occur in SCA3, which may reflect disruption of frontosubcortical pathways, independent of motor dysfunction.