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Impaired Cerebral Autoregulation in Alzheimer's Disease: A Transcranial Doppler Study
Guoyu Zhou1, Xinjing Zhao1, Zhiyin Lou2
1Department of Geriatric Neurology, Qilu Hospital of Shandong University, Jinan, China.
Insights
Alzheimer's disease (AD) patients show impaired cerebral autoregulation (CA). A supine-to-standing transcranial Doppler (TCD) test revealed significant differences in cerebral blood flow velocity curves, indicating reduced CA efficiency in AD.
Area of Science:
- Neurology
- Vascular Biology
- Medical Imaging
Background:
- Alzheimer's disease (AD) is associated with vascular changes.
- These vascular pathologies may compromise cerebral autoregulation (CA).
Purpose of the Study:
- To evaluate cerebral autoregulation (CA) in Alzheimer's disease (AD) patients.
- To utilize transcranial Doppler (TCD) for assessing CA during postural changes.
Main Methods:
- Employed transcranial Doppler (TCD) in 61 participants (31 AD patients, 30 controls).
- Measured cerebral blood flow velocities (CBFV) during supine-to-standing transitions.
- Analyzed CBFV curve parameters, including spike slopes and angles, to assess CA.
Main Results:
- Significant differences observed in CBFV curve parameters (X spike slope, W spike slope, α angle) between AD patients and controls.
- Receiver operating characteristic (ROC) analysis indicated diagnostic value for these parameters (AUC values ranging from 0.664 to 0.775).
- AD patients exhibited decreased efficiency in CBFV curve changes upon standing.
Conclusions:
- The supine-to-standing TCD test is a valuable tool for evaluating CA in AD.
- Impaired CA in AD is characterized by less efficient CBFV curve adjustments.
- Findings suggest neurovascular unit involvement in AD pathogenesis.
Background:
Vasculature changes have been observed in Alzheimer's disease (AD). AD-related vascular pathology might impair cerebral autoregulation (CA).
Objective:
This study was designed to evaluate CA of AD patients by using transcranial doppler (TCD).
Methods:
A total of 61 participants were included in the study, including 31 AD patients and 30 controls. The trend curves of cerebral blood flow velocities (CBFV), pulsatility index, and resistance index were obtained using TCD during supine-to-standing posture changes. CA was measured by the changes of CBFV curves during supine-to-standing test.
Results:
There were two spikes named X spike and W spike that appeared in the CBFV curve when the subjects stood abruptly. The slope of the X spike descending branch, the slope of the W spike ascending branch, and the angle between X and W spikes (α angle), showed significant differences between the experimental and control groups (2.34±0.99 versus 3.15±1.61 cm/s2, p = 0.021; 2.31±0.81 versus 3.38±1.18 cm/s2, p < 0.001; and 52.71±20.26 versus 41.4±12.87 degrees, p = 0.012, respectively). ROC analysis showed that AUCαangle is 0.664 (p = 0.028) and that AUCSAB and AUCadjustedSAB are 0.775 and 0.738, respectively (both p < 0.001).
Conclusions:
Our study demonstrated that supine-to-standing TCD test is a valuable tool for the evaluation of CA in AD patients. Impaired CA in AD patients manifested as decreased efficiency of changes in the CBFV curve. Neurovascular units were involved in the pathogenesis of AD.
