Altered spontaneous brain activities in maintenance hemodialysis patients with cognitive impairment and the construction of cognitive function prediction models

Figures & data

Table 1. General information and laboratory tests for the three groups of subjects.

Variables	MHD-CI (n = 30)	MHD-NCI (n = 20)	HC (n = 28)	Statistical values	p value
Age (years))	49.53 ± 8.23	47.00 ± 10.87	47.57 ± 10.22	0.497	.610^C
Gender (male/female)	18/12	15/5	14/14	3.046	.218^χ^2
Educational level (years)	9.00 (5.75–9.00)	9.00 (8.25–9.00)	8.00 (6.00–9.00)	3.109	.211^D
MOCA (points)	23.00 (17.00–24.00)^a,^b	28.00 (27.00–29.00)	26.00 (26.00–27.00)	61.570	<.001^D
Duration of dialysis (years)	3.00 (1.00–4.75)	1.50 (1.00–3.00)	–	−1.287	.198^B
Red blood cells (×10^9/L)	3.44 ± 0.50^a	3.60 ± 0.45^a	4.46 ± 0.60	28.784	<.001^C
Leukocytes (×10^9/L)	5.91 ± 2.28	5.85 ± 1.66	5.73 ± 1.98	0.056	.946^C
Hemoglobin (g/L)	96.16 ± 15.73^a,^b	112.95 ± 9.25^a	116.07 ± 7.91	22.678	<.001^C
Hematocrit (%)	32.90 (29.85–36.37)	33.00 (28.92–35.00)	34.00 (32.50–36.70)	3.315	.191^D
Albumin (g/L)	37.85 (34.57–40.70)^a	39.15 (36.00–42.47)^a	42.20 (39.97–45.70)	16.585	<.001^D
Glucose (mmol/L)	4.84 (4.50–5.51)	4.74 (4.38–5.62)	5.05 (4.43–6.42)	1.271	.530^D
Blood urea nitrogen (mmol/L)	30.69 ± 6.17^a,^b	21.19 ± 7.39^a	5.67 ± 2.12	151.671	<.001^C
Creatinine (μmol/L)	787.21 ± 342.55^a	904.32 ± 481.21^a	61.28 ± 10.30	52.286	<.001^C
Uric acid (μmol/L	313.69 ± 154.20	351.03 ± 152.37	290.11 ± 91.21	1.199	.307^C
Triglycerides (mmol/L)	1.45 ± 0.62	1.64 ± 1.13	1.26 ± 0.51	1.463	.238^C
Cholesterol (mmol/L)	4.05 ± 1.25	3.79 ± 1.03	3.91 ± 0.69	0.388	.680^C
Blood sodium (mmol/L)	140.08 ± 2.73	139.81 ± 2.26	139.55 ± 2.96	0.273	.762^C
Blood potassium (mmol/L)	4.11 (3.80–4.74)	4.35 (3.86–4.68)	4.10 (3.5–4.56)	1.905	.386^D
Blood calcium (mmol/L)	2.19 (2.04–2.36)	2.16 (2.08–2.34)	2.42 (1.94–2.68)	0.535	.765^D
Blood phosphorus (mmol/L)	1.94 (1.44–2.37)^a	1.80 (1.61–2.04)^a	1.18 (0.85–1.80)	12.870	.002^D
Parathyroid hormone (ng/L)	295.45 (136.70–453.72)^a	288.50 (128.27–405.82)^a	22.15 (17.47–42.27)	48.780	<.001^D
HCO3^− (mmol/L)	19.38 ± 1.76^a	18.79 ± 1.83^a	23.39 ± 1.08	66.03	<.001^C
Kt/V (ml-s-1/1.73 m^2)	1.51 ± 0.06	1.54 ± 0.09	–	5.465	.259^A

MHD-CI: maintenance hemodialysis patients with cognitive impairment; MHD-NCI: maintenance hemodialysis patients without cognitive impairment; HC: healthy controls. MOCA: Montreal Cognitive Assessment scale, Kt/V: dialysis effectiveness index. A: Independent samples t-test; B: Mann–Whitney U-test; C: a test of variance (ANOVA); D: Kruskal–Wallis test t; χ²: chi-square test.^astatistically significant difference in the MHD-CI group/MHD-NCI group compared to HC (p < .05).

^bstatistically significant difference in the MHD-CI group compared to the MHD-NCI group (p < .05).

Table 2. Multiple comparison results of post-hoc tests of three groups of clinical variables.

Variables	Groups	Standard error	p value
Red blood cells	1–2	0.154	.666
	1–3	0.140	<.001
	2–3	0.156	<.001
Hemoglobin	1–2	3.416	<.001
	1–3	3.109	<.001
	2–3	3.464	.267
Blood urea nitrogen	1–2	1.586	<.001
	1–3	1.444	<.001
	2–3	1.609	<.001
Creatinine	1–2	93.128	.212
	1–3	84.770	<.001
	2–3	94.449	<.001
MOCA scores	1–2	6.448	<.001
	1–3	5.870	<.001
	2–3	6.540	.064
Albumin	1–2	6.539	.162
	1–3	5.952	<.001
	2–3	6.631	.024
Blood phosphorus	1–2	6.540	.872
	1–3	5.953	.001
	2–3	6.633	.005
HCO3^−(mmol/L)	1–2	0.454	.202
	1–3	0.414	<.001
	2–3	0.454	<.001
Parathyroid hormone	1–2	6.541	.977
	1–3	5.954	<.001
	2–3	6.634	<.001

Group 1 MHD-CI: maintenance hemodialysis patients with cognitive impairment; Group 2 MHD-NCI: maintenance hemodialysis patients without cognitive impairment; Group 3 HC: healthy controls.

Figure 1. Clusters with significantly altered mALFF values among groups. The blue-yellow areas denote lower mALFF values in the MHD-CI group than in the (A) MHD-NCI group or (B) HC group. mALFF: mean low-frequency amplitude; MHD-CI: maintenance hemodialysis patients with cognitive impairment; MHD-NCI: maintenance hemodialysis patients without cognitive impairment; HC: healthy controls.

Figure 2. Clusters with significantly altered mALFF values among groups. The red-yellow areas denote higher mALFF values in the MHD-CI group than in the (A) MHD-NCI group or (B) HC group; (C) MHD-NCI group compared to the HC group. mALFF: mean low-frequency amplitude; MHD-CI: maintenance hemodialysis patients with cognitive impairment; MHD-NCI: maintenance hemodialysis patients without cognitive impairment; HC: healthy controls.

Table 3. Significant differences in mALFF values among groups.

		MNI
Condition	Brain Regions	X	Y	Z	Voxel size	Z value	p value
MHD-CI > MHD-NCI	caudate nucleus R	18	18	42	11	3.441	<.001
MHD-CI > HC	fusiform gyrus L	−30	−9	−33	31	3.702	<.001
	parahippocampal L	−18	0	−21	27	4.137	<.001
	hippocampus R	21	−24	−12	34	4.634	<.001
	caudate nucleus L	−12	15	24	26	4.321	<.001
	caudate nucleus R	15	18	12	16	3.728	<.001
MHD-CI < MHD-NCI	postcentral L	−45	−27	51	11	−3.678	<.001
MHD-CI < HC	postcentral L	−51	−33	48	19	−3.821	<.001
MHD-NCI > HC	hippocampus R	30	−21	−18	11	3.534	<.001

mALFF: mean low-frequency amplitude; MHD-CI: maintenance hemodialysis patients with cognitive impairment; MHD-NCI: maintenance hemodialysis patients without cognitive impairment; HC: healthy controls; MNI: Montreal Neurological Institute.

Figure 3. Clusters with significantly altered mfALFF values among groups. The blue-yellow areas denote lower mfALFF values in the MHD-CI group than in the (A) MHD-NCI group or (B) HC group; (C) MHD-NCI group compared to the HC group. mfALFF: mean ratio low-frequency amplitude; MHD-CI: maintenance hemodialysis patients with cognitive impairment; MHD-NCI: maintenance hemodialysis patients without cognitive impairment; HC: healthy controls.

Table 4. Significant differences in mfALFF values among groups.

		MNI
Condition	Brain Regions	X	Y	Z	Voxel size	Z value	p value
MHD-CI < MHD-NCI	inferior temporal gyrus L	−45	−45	−30	14	−4.208	<.001
MHD-CI < HC	medial superior frontal gyrus L	0	54	18	17	−4.233	<.001
MHD-NCI < HC	medial superior frontal gyrus L	6	51	12	11	−3.534	<.001

MHD-CI: maintenance hemodialysis patients with cognitive impairment; MHD-NCI: maintenance hemodialysis patients without cognitive impairment; HC: healthy controls; mfALFF: mean ratio low-frequency amplitude; MNI: Montreal Neurological Institute.

Figure 4. Clusters with significantly altered mReHo values among groups. (A) The blue-yellow areas denote lower mReHo values in the MHD-CI group than in the HC group. (B) The red-yellow areas denote higher mfALFF values in the MHD-CI group than in the HC group. mReHo: mean regional concordance; MHD-CI: maintenance hemodialysis patients with cognitive impairment; MHD-NCI: maintenance hemodialysis patients without cognitive impairment; HC: healthy controls.

Table 5. Significant differences in mReHo values among groups.

		MNI
Condition	Brain Regions	X	Y	Z	Voxel size	Z value	p value
MHD-CI < HC	supraoccipital gyrus L	−18	−96	15	14	−3.801	<.001
MHD-CI > HC	rolandic operculum L	−48	0	12	19	3.815	<.001

MHD-CI: maintenance hemodialysis patients with cognitive impairment; HC: healthy controls; mReHo: mean regional concordance; MNI: Montreal Neurological Institute.

Figure 5. (A) Correlation analysis of the mALFF values in left postcentral gyrus and MOCA score; (B) Correlation analysis of the mfALFF values in left inferior temporal gyrus and MOCA score; (C) Correlation analysis of hemoglobin level and MOCA scores; (D) Correlation analysis of urea nitrogen level and MOCA scores; (E) Correlation analysis of the mALFF values in right caudate and MOCA score.

Figure 6. Back propagation neural network model. (A) Actual scores and predicted scores of BPNN based on Hb and BUN values. (B) actual scores and predicted scores of BPNN based on Hb, BUN, and mALFF values in the right caudate nucleus. (C) actual scores and predicted scores of BPNN based on Hb, BUN, and mALFF values in the left postcentral gyrus. (D) actual scores and predicted scores of BPNN based on Hb, BUN, and mALFF values in the left postcentral gyrus and right caudate nucleus. The dots in the figures indicate the subjects included in the test set of prediction models.

Figure 7. Validation cohort of BPNN model.

Table 6. The input layer data for the validation cohort.

Variables (n = 15)	Age (years)	Gender (male/female)	MOCA (points)	Hemoglobin (g/L)	Blood Urea Nitrogen (mmol/L)	mALFF (PoCG-L)
	52 (41–57)	7/8	20.87 ± 5.48	104.53 ± 11.47	26.93 ± 8.09	0.78 ± 0.11

mALFF(PoCG-L): the mALFF values of the left center postcentral gyrus.

Data availability statement

The datasets generated and analyzed during the current study are not publicly available because they constitute an excerpt of research in progress but are available from the corresponding author on reasonable request.