BACKGROUND Myotonic dystrophy type 1 (MD1), or Steinert's disease, is a multisystemic disorder of autosomal dominant inheritance, whose adult variant usually presents with multidomain cognitive impairment and affects patients' functionality and quality of life. OBJECTIVE To study the four-year history of cognitive functioning in a sample of patients with the adult variant of MD1. METHODS The neurocognitive functions of a sample of 31 patients with MD1 are evaluated, of whom 24 repeat the test administered four years ago in the Neurology Service of the Complejo Hospitalario of Navarra. Data are collected from the cognitive domains that are most related to the deficits that usually present in MD1. RESULTS The follow-up evaluation found that the visuospatial and visuoconstructive functions and alternating attention of the patients who underwent the study were affected, as was their daily functioning reported by the family. These results are in line with those obtained four years earlier, with no significant deterioration observed between the two measurements. A higher incidence of cognitive impairment was also displayed in 2018, with some cases of progression to dementia in Steinert's disease. CONCLUSIONS Neurocognitive progression in MD1 seems to respond to a progressive pattern of degeneration, linked to the functions that are most affected from the beginning of the sequelae phase and which usually correspond to the domains of working memory, alternating attention, and visuospatial and visuoconstructive abilities.