Study: a neuropsychological rehabilitation program using CogniFit improved daily functioning in a single case of mild neurocognitive disorder

Obstructive sleep apnea-hypopnea syndrome (OSAHS) is a chronic condition in which the upper airway repeatedly collapses during sleep, producing intermittent hypoxia, sleep fragmentation and, in a substantial minority, cognitive consequences. The authors cite the Wisconsin Sleep Cohort finding that 17% of men and 9% of women aged 50 to 70 have moderate-to-severe OSAHS, an estimated Colombian prevalence of 26.8%, and a literature estimate that around 26% of people with OSAHS can develop cognitive impairment, executive functions among the domains most affected.^[1]

Against that background, a 2023 case study in the Revista Iberoamericana de Psicología set out to establish the effect of a neuropsychological rehabilitation program, built around executive-function training delivered partly through the CogniFit platform, on the daily functioning of one such patient.

What the study tested

The study used a single-case (N = 1) quasi-experimental design with an A-B, non-reversal structure, in which the patient served as his own control. It was conducted at the Fundación Instituto Neurológico de Colombia in Medellín, approved by the institutional ethics committee with informed consent, and classified as "minimal-risk research" under Colombian regulations.^[1]

The patient was a 51-year-old, right-handed, high-school-educated man referred from neurology for suspected cognitive decline. Assessment found an average IQ (WAIS-IV total = 93) and a Mini-Mental State Examination score of 28, with no impairment of basic memory, gnosis, praxis or language, but severe compromise of executive functions in the orbitofrontal and dorsolateral regions on the BANFE battery. Polysomnography confirmed moderate obstructive sleep apnea; he was not yet using CPAP because of pandemic-related delays and took no cognition-affecting medication. He met DSM-5 criteria for mild neurocognitive disorder and an unspecified anxiety disorder.

Measurement followed a repeated-measures schedule: three baseline measurements every two weeks over six weeks to verify behavioral stability, then four treatment measurements across ten weeks. The primary functional instrument was the BRIEF-A (Behavior Rating Inventory of Executive Function, Adult, Spanish version), which yields a Global Executive Composite and was completed at each point by both the patient and a family informant. The Hamilton Anxiety Scale (14 items) was administered to the patient only.

The intervention followed the Sohlberg and Mateer executive-rehabilitation model, selection and execution of plans, time control, and behavioral self-regulation, delivered through 40 sessions on the CogniFit platform, 6 pencil-and-paper sessions, and a home therapeutic guide. CogniFit sessions ran four times per week at roughly 20-30 minutes each; the plan opened with 8 sessions on complex attention, then 32 sessions of executive-function work targeting cognitive flexibility, planning, working memory, monitoring and inhibition.

What it found

Because group statistics do not apply to a single case, the authors evaluated the change with three established single-case overlap metrics, the percentage of non-overlapping data (PND), the percentage of data exceeding the median (PEM), and the non-overlap of all pairs (NAP), on both raters' BRIEF-A Global Executive Composite scores.

Across both raters, PND and PEM reached 80%, which the authors classified as "quite effective" and "moderately effective" respectively, while NAP reached 86.6% for the patient's ratings and 90% for the informant's, both interpreted as a medium effect. The visual analysis showed stable baselines and, after the CogniFit software was introduced, a delayed level change and downward trend in BRIEF-A scores, lower scores indicate fewer everyday executive difficulties. The informant consistently perceived more dysfunction than the patient did.^[1]

The authors reported that both analyses indicated improvement in the patient's functioning, in planning, task self-monitoring, organization of daily environments, time control and information storage, alongside reductions in emotional difficulties, anger outbursts and cognitive rigidity on the BRIEF-A.

What did not change

The Hamilton Anxiety Scale told a different story. Across both the baseline and treatment phases, the authors observed a stable pattern with no change in level and no change in trend, so they did not analyze the anxiety data with the overlap methods. The program's measured benefit was confined to executive functioning and everyday behavior on the BRIEF-A; it was not accompanied by a measurable shift in the patient's anxiety symptoms.

Limitations, what this does NOT show

The authors are direct about the boundaries of a single-case design:

One patient, no generalization. The authors state that, "as a single case, its conclusions are not generalizable," even though the design can illuminate favorable results from rehabilitation using cognitive-training platforms. There is no control group beyond the patient's own baseline and no randomization, so practice effects and natural variation cannot be separated from the intervention.

Constraints set by the patient's situation. His circumstances limited the number of sessions, his access to psychological treatment and the ordering of CPAP, and the rehabilitation lacked the multidisciplinary approach the authors regard as essential in OSAHS, where airway and cognitive-emotional treatment should run together.

No long-term follow-up. The authors recommend future studies with larger samples, a longer treatment period, follow-up after the program ends and repeated cognitive assessment. Whether the BRIEF-A gains persist after training stops is untested.

Where this fits in the broader evidence

Sleep-disordered breathing has been linked to cognitive risk at scale: a 2017 systematic review and meta-analysis in JAMA Neurology (Leng et al.) associated it with higher odds of cognitive impairment. Earlier work cited by the authors used computerized cognitive training, including the CogniFit platform, in older adults with insomnia (Haimov & Shatil, 2013), and Cochrane reviewers have examined cognitive rehabilitation for executive dysfunction after acquired brain injury (Chung et al., 2013). This 2023 case extended that line into mild neurocognitive disorder due to OSAHS, focused on real-world functioning rather than test scores alone. For the full catalog of research on CogniFit's technology, see the research index; for a related overview, see CogniFit's page on cognitive rehabilitation after stroke.