Alteraciones cognitivas en pacientes con hidrocefalia crónica del adulto (“normotensiva”). Propuesta de un protocolo para su evaluación clínica

Serial Tap Test of patients with idiopathic normal pressure hydrocephalus: impact on cognitive function and its meaning

Background

Idiopathic normal pressure hydrocephalus (INPH) is characterized by gait disturbance, urinary incontinence and cognitive decline. Symptoms are potentially reversible and treatment is based on cerebrospinal fluid shunting. The tap test (TT) is used to identify patients that will benefit from surgery. This procedure consists of the withdrawal of 20 to 50 mL of cerebrospinal fluid (CSF) through a lumbar puncture (LP) after which the symptoms of the triad are tested. Improvement in the quality and speed of gait are already recognized but cognitive improvement depends on several factors such as tests used, the time elapsed after LP for re-testing, and the number of punctures. Serial punctures may trigger similar conditions as external lumbar drainage (ELD) to the organism.

Objective

This study aimed to identify how serial punctures affect cognition to increase the sensitivity of the test and consequently the accuracy of surgical indication.

Methods

Sixty-one patients with INPH underwent baseline memory and executive tests repeatedly following the 2-Step Tap Test protocol (2-STT – two procedures of 30 mL lumbar CSF drainage separated by a 24-h interval). The baseline scores of INPH patients were compared with those of 55 healthy controls, and with intragroup post-puncture scores of the 2-STT.

Results

The group with INPH had lower performance than the control group in all cognitive tests (RAVLT, Stroop, CFT, FAR-COWA, FAB, MMSE, orientation, mental control), except for the forward digit span test (p = 0.707). After conducting LP procedures, the Stroop test (words, colors and errors), RAVLT (stage A1, A6 and B1), and CFT (immediate and delayed R) scores were equal to those of the control group (p > 0.05). The INPH group presented significant improvement after the first puncture in MMSE (p = 0.031) and in the Stroop Test (points) (p < 0.001). After the second puncture, subjects improved in orientation, MMSE, RAVLT (B1), Stroop (points, words, errors) and CFT (IR).

Conclusion

Progressive cognitive improvement occurred over the 2-STT and changes were more significant after the second LP in all cognitive domains except for RAVLT (A7). Encephalic alert system ‘arousal’ seems to participate in early improvements observed during 2-STT. The second LP increased the sensitivity of the drainage test to detect changes in cognitive variables, and consequently improved the quality of the method.

Development of the Brazilian Portuguese version of the "Grading scale for idiopathic normal pressure hydrocephalus": cross-cultural adaptation, reliability and validity

OBJECTIVE

The current study translated to Portuguese and validated the normal pressure hydrocephalus (NPH) scale originally developed in English as the Grading Scale for Idiopathic Normal Pressure Hydrocephalus.

METHODS

Following Guillemin's validation protocol, the last version of the Portuguese NPH scale was applied to 121 consecutive patients with a diagnosis of normal pressure hydrocephalus (73 men and 48 women) from the Group of Cerebral Hydrodynamics from July 2010 to March 2012.

RESULTS

The mean age was 71.09 years old, ranging from 35 to 92 years. The rate of agreement and reproducibility was high, as confirmed by Cohen's Kappa coefficient, with excellent intraobserver correlation for the NPH scale items individually evaluated: gait (0.80), dementia (0.90) and incontinence (0.87).

CONCLUSIONS

The Portuguese version of the Grading Scale for Idiopathic Normal Pressure Hydrocephalus was successfully translated and validated for use in Brazilian patients.

[Long-term prognosis of idiopathic chronic adult hydrocephalus: I. The University Hospital Marqués de Valdecilla diagnostic and therapeutic protocol]

INTRODUCTION

Despite the existence of published guidelines for more than a decade, there is still a substantial variation in the management of idiopathic normal pressure hydrocephalus due to its diagnostic and therapeutic complexity.

DEVELOPMENT

The diagnostic and therapeutic protocol for the management of idiopathic normal pressure hydrocephalus in use at the Department of Neurosurgery of the University Hospital Marqués de Valdecilla is presented. The diagnostic process includes neuropsychological testing, phase contrast cine MRI, urodynamic evaluation, continuous intracranial pressure monitoring, cerebrospinal fluid hydrodynamics by means of lumbar infusion testing, and intra-abdominal pressure measurement. A patient is considered a surgical candidate if any of the following criteria is met: mean intracranial pressure >15mmHg, or B-waves present in >10% of overnight recording; pressure-volume index <15ml, or resistance to cerebrospinal fluid outflow (R_OUT) >4.5mmHg/ml/min in bolus infusion test; R_OUT >12mmHg/ml/min, intracranial pressure >22mmHg, or high amplitude B-waves in the steady-state of the continuous rate infusion test; or a clinical response to high-volume cerebrospinal fluid withdrawal.

CONCLUSIONS

The implementation of a diagnostic and therapeutic protocol for idiopathic normal pressure hydrocephalus management could improve various aspects of patient care. It could reduce variability in clinical practice, optimise the use of health resources, and help in identifying scientific uncertainty areas, in order to direct research efforts in a more appropriate way.