Cognitive sequelae associated with parenchymal and extraparenchymal neurocysticercosis

While the incidence of neurocysticercosis (NC) with viable parasites has been declining in Mexico and some other countries, this trend is not observed globally, and the burden of patients who have previously suffered from NC remains considerable. Cognitive manifestations are often overlooked in the clinical management of NC. In routine practice, patients are generally considered cured once viable parasites are no longer detectable, despite the potential for persistent neurological sequelae.

To evaluate the frequency, characteristics, and severity of cognitive sequelae in patients with a history of NC.

We conducted a cross-sectional, descriptive study at the National Institute of Neurology and Neurosurgery in Mexico City, between 2022 and 2024, involving 105 patients with a history of neurocysticercosis who had no viable parasites at the time of inclusion. Patients were categorized into three groups: parenchymal NC with a single calcification, parenchymal NC with multiple calcifications, and healed extraparenchymal NC who, at the time of NC diagnosis, had intracranial hypertension requiring ventriculoperitoneal shunt placement. Cognitive function was assessed using the Mini-Mental State Examination (MMSE) and the Montreal Cognitive Assessment (MoCA). Results were compared to those from a healthy control group, matched with patients by age, sex and educational level.

The results highlight a significant cognitive impairment in patients with a history of NC compared to controls: MMSE: 22 (Boppré et al., 2001- (Tseng et al., 2024) vs. 26 (Tseng et al., 2024- (Helmstaedter and Witt, 2017), p < 0.0001; MoCA: 20 (Tombaugh and McIntyre, 1992; Aguilar-Navarro et al., 2018; Cervigni et al., 2022; Del Brutto et al., 2019; Boppré et al., 2001; Rodrigues et al., 2012; Rabearisoa et al., 2024) vs. 25 (Rabearisoa et al., 2024; Hamamoto Filho et al., 2019; Tseng et al., 2024; Koivisto et al., 2013; Xiao et al., 2022; Helmstaedter and Witt, 2017), p < 0.0001. When comparing the three groups of patients, MMSE results showed a higher frequency of dementia in the patients with history of extraparenchmal NC (18 %) compared to the patients with history of parenchymal NC (0 %), p=0.001, while frequency of mild cognitive impairment was higher in the parenchymal group (78 %) vs. extraparenchymal grup (47.3 %), p=0.003. Notably, cognitive function was not influenced by the presence of active epilepsy, its treatment, or prior pharmacological or surgical interventions specific to NC. The MMSE and MoCA scores showed a significant positive correlation when all individuals included in the study were taken into account (r = 0.65, p < 0.0001), and this correlation remained significant when each patient subgroup was analyzed separately.

The results of this work indicate that NC is associated with substantial cognitive sequelae, that should be recognized and addressed as part of comprehensive patient care.