## 1 Introduction
[24] successfully designed a smartphone-guided errorless learning intervention for a patient with acquired topographic disorientation disorder. As far as we know, errorless route learning in patients with KS has only been tested yet by [PERSON] et al. [18]. The researchers did not find a difference between errorless and trial-and-error learning, but the results were suggestive for some residual learning potential in KS. Possible limitations in [PERSON] et al. 's study were that the route length was relatively short, and the learning took place in a rather familiar environment. This may have caused relatively fast learning with low error rates from the start. It thus could have obscured any learning differences between the two conditions. Errorless skill learning has been shown to form a very effective memory rehabilitation method for patients with KS. Route learning may be viewed as a type of skill learning that could increase autonomy and quality of life in trainees. However, there is hardly any literature yet on errorless route learning. In light of the foregoing, the aim of the present paper was to further study route learning potential in patients with KS, in particular comparing errorless route learning to trial-and-error learning and passive learning (i.e., following a guide). In the present study, we used a longer route with more turns and a less well-known route environment together with a larger patient group than in the study by [PERSON] et al. [18]. Moreover, we employed new errorless instructions that emphasized active exploration of the environment during the training. As such, the creation of what is called a cognitive map could also be stimulated. We will return to this in the Discussionsection. Three groups of patients diagnosed with KS, following one out of three learning methods (passive, trial-and-error, and errorless learning) were trained on a specific route over several weeks. It has already been pointed out a number of times that patients might gain satisfaction, stronger feelings of independence, and a higher subjective quality of life by learning new skills and new routes [9; 10; 21]. Therefore, a second question of interest was whether any gain in route knowledge also enhanced quality of life in the patient groups. Accordingly, we also collected measures of subjective and proxy-estimated quality of life during the training. The present setup allowed us to address two further questions of secondary interest. The first question concerned changes in physical fitness in the participants over the course of the training. Patients with KS are not only cognitively affected; they also typically suffer poor physical fitness. This can already be seen in the early stages of the disease. [PERSON] et al. [25] reported a case of Wernicke encephalopathy with severe physical and mobility deficits. [PERSON] et al. [26] found 98% of 64 hospitalized patients with KS to be lower than the control norm on the six-minute walking test (6 MWT), indicative of diminished physical fitness. We therefore examined whether the route training caused any physical fitness gains as measured by the 6 min walking test. The possibility of fitness gains in our training triggered a second question of secondary interest. In the last decades, several neuropsychological lines of research have looked at how physical exercise can affect brain functioning both in terms of neural organization and density and of cognitive functioning. Meta-analyses have demonstrated positive effects of physical activity on cognition in persons with MCI [27], Alzheimer's disease [28], and diverse types of dementia [29]. Other studies and reviews, however, reported no or mixed effects of physical exercise in older people with cognitive decline [30; 31; 32]. In the present study, we explored cognitive functioning across a range of domains before and after the route training.