Abstract
BackgroundWe tested the hypothesis that paradigms from the Addenbrooke’s Cognitive Examination (ACE-III), including those that had not been studied using TCD previously (novel) versus those which had been (established), would elicit changes in CBF velocity (CBFv). New methodHealthy subjects were studied with bilateral transcranial Doppler (TCD), beat-to-beat blood pressure (Finapres), continuous electrocardiogram (ECG), and end-tidal CO2 (nasal capnography). After a 5-min baseline recording, cognitive tests of the ACE-III were presented to subjects, covering attention (SUB7, subtracting 7 from 100 sequentially), language (REP, repeating words and phrases), fluency (N-P, naming words), visuospatial (DRAW, clock-drawing), and memory (MEM, recalling name and address). An event marker noted question timing. ResultsForty bilateral data sets were obtained (13 males, 37 right-hand dominant) with a median age of 31 years (IQR 22-52). Population normalized mean peak CBFv% in the dominant and non-dominant hemispheres, respectively, were: SUB7 (11.3±9.6%, 11.2±10.5%), N-P (12.7±11.7%, 11.5±12.0%), REP (12.9±11.7%, 11.6±11.6%), DRAW (13.3±11.7%, 13.2±15.4%) and MEM (13.2±10.3%, 12.0±10.1%). There was a significant difference between the dominant and non-dominant CBFv responses (p<0.008), but no difference between the amplitude of responses. Comparison with existing methodsFor established paradigms, our results are in excellent agreement to what has been found previously in the middle cerebral artery. ConclusionsCognitive paradigms derived from the ACE-III led to significant lateralised changes in CBFv that were not distinct for novel paradigms. Further work is needed to assess the potential of paradigms to improve the interpretation of cognitive assessments in patients at risk of mild cognitive impairment.
Highlights
By 2050, 135.5 million people are predicted to be living with dementia worldwide (Robinson et al 2015); cognitive impairment having a great impact on the patient, and on their relatives, carers and health care providers
Some of the tests representing each of the five domains of the Addenbrooke's Cognitive Examination-III (ACE-III) would be expected to elicit a significant cerebral blood flow (CBF) velocity (CBFv) response (SUB7, N-P), the other three tests (REP, DRAW, MEM) have not been previously assessed in their ability to reflect increases in metabolic demand associated with transient neural activation
The DRAW paradigm demonstrated the greatest peak CBFv bilaterally out of all five paradigms and lowest CBFv responses were observed for the SUB7 and MEM paradigms
Summary
By 2050, 135.5 million people are predicted to be living with dementia worldwide (Robinson et al 2015); cognitive impairment having a great impact on the patient, and on their relatives, carers and health care providers. Transcranial Doppler ultrasound (TCD) is a non-invasive tool used to continuously monitor CBF velocity (CBFv) in major vessels such as the middle cerebral artery. We tested the hypothesis that paradigms from the Addenbrooke’s Cognitive Examination (ACE-III), including those that had not been studied using TCD previously (novel) versus those which had been (established), would elicit changes in CBF velocity (CBFv). New Method: Healthy subjects were studied with bilateral transcranial Doppler (TCD), beat-to-beat blood pressure (Finapres), continuous electrocardiogram (ECG), and end-tidal CO2 (nasal capnography). Comparison with Existing Methods: For established paradigms, our results are in excellent agreement to what has been found previously in the middle cerebral artery. Conclusions: Cognitive paradigms derived from the ACE-III led to significant lateralised changes in CBFv that were not distinct for novel paradigms. Further work is needed to assess the potential of paradigms to improve the interpretation of cognitive assessments in patients at risk of mild cognitive impairment
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
