Neurocognitive functions and brain atrophy after proven neuroborreliosis: a case-control study

Background: Patients often report neurocognitive difficulties after neuroborreliosis (NB). The frequency and extent of cognitive problems in European patients have been studied incompletely. Methods: Sixty patients received a neurological and neuropsychological work-up 6 months or longer after treatment for proven NB. Quality of life, psychiatric symptom load, and brain atrophy were measured. All results were compared with a group of 30 healthy control persons adapted for age, gender and education being serologically negative for Borrelia burgdorferi senso latu. A cognitive sum score and a global sum score including cognitive, psychological results and quality of life data was calculated for both groups. Results: Patients after NB showed a lower (i.e. more impaired) score on the Scripps Neurological rating scale (SNRS), but the observed neurological deficits were generally mild (mean +/- SD: 97.1 +/- 4.7 vs. 99.1 +/- 2.4, p = 0.02). The mean neuropsychological domain results of the NB group were all within the normal range. However, a lower performance was found for the frontal executive function z-values (mean +/- SD-0.29 +/- 0.60 vs. 0.09 +/- 0.60; p = 0.0059) of NB patients. Comparing the global sum score (mean +/- SD 11.3 +/- 4.2(NB) vs. 14.3 +/- 2.9(control), p = 0.001) and the cognitive sum score of the NB group with those of the control group (mean +/- SD -0.15 +/- 0.42(NB) vs. 0.08 +/- 0.31(control), p = 0.0079), both differences were statistically different. The frequencies of impaired global sum scores and those of the pathological cognitive sum scores (p = 0.07) did not differ statistically. No significant differences were found for health-related quality of life (hrQoL), sleep, psychiatric symptom load, or brain atrophy. Conclusion: The mean cognitive functions of patients after proven NB were in the normal range. However, we were able to demonstrate a lower performance for the domain of frontal executive functions, for the mean cognitive sum score and the global sum score as a sign of subtle but measurable sequelae of neuroborreliosis. Brain atrophy is not a common consequence of neuroborreliosis.