Decreased Vascular Pulsatility in Alzheimer’s Disease Dementia Measured by Transcranial Color-Coded Duplex Sonography

Figures & data

Table 1 Characteristics of HC and ADD Participants

Variable	Healthy Control (HC)	Dementia Due to Alzheimer’s Disease (ADD)	p-value
Numbers	14	12
Sex (male:female)	6:8 (42.9%:57.1%)	6:6 (50.0%:50.0%)	1.000
Arterial hypertension (present:absent)	6:8 (42.9%:57.1%)	7:5 (58.3%:41.7%)	0.695
Treatment for hypertension (yes:no)	6:8 (42.9%:57.1%)	7:5 (58.3%:41.7%)	0.695
AChEI treatment (yes:no)	1:13 (7.1%:92.9%)	8:4 (66.7%:33.3%)	<0.001
Caffeine (yes:no)	14:0 (100.0%:0.0%)	9:3 (75.0%:25.0%)	0.085
Nicotine (yes:no)	1:13 (7.1%:92.9%)	1:11 (8.3%:91.7%)	1.000
Variable mean ± SD (range)
Age at examination (in years)	65.4 ± 7.85 (54.0–78.0)	71.3 ± 9.49 (54.0–84.0)	0.076
Z-Score MMSE	−0.2 ± 1.09 (–2.4–1.2)	−9.9 ± 7.08 (–21.9- −1.6)	<0.001
CERAD-sum score	85.8 ± 8.60 (68.0–97.0)	47.8 ± 14.43 (25.0–79.0)	<0.001
CDR global	0.0 ± 0.00 (0.0–0.0)	1.3 ± 0.45 (1.0–2.0)	<0.001
CDR-SOB	0.0 ± 0.00 (0.0–0.0)	6.1 ± 2.84 (3.5–14.0)	<0.001
Awake for (in hours)	6.4 ± 1.05 (4.8–8.0	6.4 ± 1.06 (4.5–8.0)	0.940
Sleep duration last night (in hours)	7.9 ± 0.82 (6.8–10.0)	8.7 ± 1.11 (6.5–10.0)	0.041
Variable median; mean ± SD (range)
Mean RI MCA right	0.559 0.56 ± 0.059 (0.482–0.673)	0.614 0.61 ± 0.066 (0.496–0.703)	0.027
Mean RI MCA left	0.540 0.56 ± 0.064 (0.489–0.735)	0.589 0.61 ± 0.049 (0.551–0.700)	0.020
Mean PI MCA right	0.763 0.79 ± 0.135 (0.613–1.033)	0.880 0.90 ± 0.213 (0.629–1.320)	0.126
Mean PI MCA left	0.763 0.82 ± 0.192 (0.586–1.301)	0.870 0.93 ± 0.190 (0.735–1.353)	0.034

Notes: p-values calculated from Mann–Whitney U-test for continuous and Fisher’s exact test for nominal variables.

Abbreviations: SD, standard deviation; AChEI, treatment with acetylcholinesterase inhibitor; Caffeine/Nicotine (yes:no), consumption of caffeine/nicotine on day of examination; z-score MMSE, z-score of the Mini-Mental state examination subtest of CERAD Neuropsychological Assessment Battery; CERAD, Consortium to Establish a Registry for Alzheimer’s Disease; CDR-SOB, clinical dementia rating scale sum of boxes; RI, resistance index; PI, pulsatility index; MCA, middle cerebral artery.

Figure 1 (A–D) Resistance and pulsatility indices middle cerebral artery.

Abbreviations: RI, resistance index; PI, pulsatility index; MCA, middle cerebral artery; HC, healthy controls; ADD, Alzheimer’s disease dementia.

Table 2 ROC Analyses for RI and PI of the Right and Left MCA

	Cut Off	Sensitivity	Specificity	AUC
Mean RI right MCA	0.586	0.750	0.846	0.763
Mean RI left MCA	0.546	1.000	0.538	0.776
Mean PI right MCA	0.788	0.750	0.615	0.673
Mean PI left MCA	0.769	0.833	0.615	0.718

Abbreviations: RI, resistance index; PI, pulsatility index; MCA, middle cerebral artery; AUC, area under the curve.

Table 3 ROC Analyses for Clustered Data of RI and PI of the MCA

	AUC	95% CI	p-value
Mean RI MCA	0.723	0.534–0.912	0.021
Mean PI MCA	0.684	0.494–0.873	0.058

Abbreviations: RI, resistance index; PI, pulsatility index; MCA, middle cerebral artery; AUC, area under the curve; CI, confidence interval.

Figure 2 (A, B) ROC analyses for clustered data.

Abbreviations: ADD, Alzheimer’s disease dementia; HC, healthy controls; AUC, area under the curve; RI, resistance index; PI, pulsatility index; MCA, middle cerebral artery.

Table 4 Spearman Correlation Analyses Between the CDR SOB and the RI and PI for All Participants

	Whole Sample		AD Spectrum
	r	p-value	r	p-value
Mean RI right MCA	0.610	0.010	0.389	0.012
Mean RI left MCA	0.350	0.013	0.366	0.018
Mean PI right MCA	0.242	0.061	0.272	0.060
Mean PI left MCA	0.314	0.023	0.331	0.030

Abbreviations: CDR SOB, clinical dementia rating scale sum of boxes; RI, resistance index; PI, pulsatility index; MCA, middle cerebral artery; r, correlation coefficient.

Table 5 Minimal Sample Size Calculation

	MSS HC [n]	MSS ADD [n]
Mean RI MCA right	26	26
Mean RI MCA left	22	22
Mean PI MCA right	43	43
Mean PI MCA left	49	49

Abbreviations: RI, resistance index; PI, pulsatility index; MCA, middle cerebral artery; MSS, minimal sample size; HC, healthy control; ADD, dementia due to Alzheimer’s disease; n, number of participants.