Date Published: April 24, 2019
Publisher: Public Library of Science
Author(s): Luisa Vinciguerra, Giuseppe Lanza, Valentina Puglisi, Manuela Pennisi, Mariagiovanna Cantone, Alessia Bramanti, Giovanni Pennisi, Rita Bella, Stephen D. Ginsberg.
Although cerebral white matter lesions (WMLs) are considered as a risk factor for vascular dementia, data on their impact on cerebral hemodynamics are scarce. We test and compare transcranial Doppler (TCD) features in WML patients with or without associated cognitive impairment.
A sample of non-demented elderly patients with WMLs was consecutively recruited. Mean blood flow velocity (MBFV), pulsatility index (PI), peak systolic blood flow velocity (PSV), end-diastolic blood flow velocity (EDV), and resistivity index (RI) were recorded from the middle cerebral artery bilaterally. Global cognitive functioning, frontal lobe abilities, functional status, and WML severity were also assessed.
161 patients satisfying the clinical criteria for vascular cognitive impairment-no dementia (VCI-ND) were age-matched with 97 presenting WMLs without any cognitive deficit. VCI-ND patients exhibited a decrease in MBFV and EDV, as well as an increase in PI, RI, and PSV. Moreover, a significant correlation between all TCD parameters and the severity of executive dysfunction was observed, whereas PI, RI, and EDV were significantly correlated with the WML load.
VCI-ND showed a hemodynamic pattern indicative of cerebral hypoperfusion and enhanced vascular resistance. These changes may be considered as the TCD correlate of VCI-ND due to microcirculation pathology. TCD provides useful indices of the occurrence and severity of small vessel disease and executive dysfunction in elderly patients at risk of future dementia.
Vascular cognitive impairment (VCI) defines the wide spectrum of cognitive disorders caused by different types of cerebrovascular disease. Within this frame, the term VCI-no dementia (VCI-ND) describes those subjects whose cognitive decline is not associated with substantial functional impairment. Although VCI-ND is not necessarily predictive of a progression into overt dementia , it represents a higher risk to develop more severe forms of cognitive impairment either as major VCI or mixed degenerative and vascular dementia (VaD), especially after recurrent strokes .
From a total sample of 413 participants that were originally screened, 103 were excluded due to an MMSE ≤ 24 or a loss of autonomy according to the ADL and/or IADL scores, 25 presented with insufficient/absent acoustic transtemporal windows bilaterally, MRI was contraindicated in 21 patients due to different reasons (metallic implants, pacemakers and implantable defibrillators, claustrophobia, etc.), and 6 refused to participate. Therefore, a total of 258 subjects satisfying the study criteria were finally enrolled and classified into two groups based on the results of the neuropsychological tests: 161 VCI-ND patients (Group A) and 97 patients with WMLs without any cognitive deficit (Group B). Demographic features, vascular risk factors, neuropsychological scores, neuroradiological findings, and TCD measures are reported in Table 1.
To the best of our knowledge, this is the first TCD study investigating cerebral hemodynamics in VCI-ND patients. While different studies investigating cerebral hemodynamics in Mild Cognitive Impairment (MCI) of degenerative cause have been published, no study evaluating TCD parameters in a large cohort of non-demented patients with cognitive decline of vascular origin (VCI-ND) has been available until now.
TCD provides useful indices of correlation between WMLs and executive dysfunction in VCI-ND. Since the cerebral hypoperfusion is regarded as both a risk factor and an aggravating component of cognitive decline in the elderly, TCD represents a valuable tool to screen subjects at risk of both vascular and mixed dementia. Future studies are needed to acquire a more comprehensive understanding of the complex relationships between hemodynamic changes, WMLs, and cognitive decline. The possibility to early detect any marker of transition into overt dementia will support clinicians towards a more careful diagnosis and management of this population at risk.