The importance of clinical normative data for conceptualizing neuropsychological deficits in people with schizophrenia spectrum disorders

Figures & data

Table 1. Descriptive statistics for patients with schizophrenia spectrum disorder on the RBANS.

	RBANS indices
Groups	Immediate memory	Visuospatial/ Constructional	Language	Attention	Delayed memory	Total scale
All patients (N = 335)
Mean (SD)	78.50 (20.70)	86.50 (17.34)	77.48 (17.94)	69.67 (19.47)	79.02 (20.97)	68.98 (19.09)
Median (IQR)	78.00 (66–92)	90.00 (77–102)	78.00 (66–89)	70.00 (55–83)	80.00 (70–91)	69.00 (54–82)
Skew/Kurtosis	0.08/−0.36 (Y)	−0.74/−0.24 (N)	−0.19/−0.34 (N)	0.04/−0.50 (N)	−0.23/−0.28 (N)	0.20/−0.68 (N)
Men (n = 208)
Mean (SD)	80.80 (19.83)	88.91 (15.96)	78.87 (17.65)	71.21 (18.80)	80.41 (20.14)	71.06 (18.25)
Median (IQR)	80.00 (68–95)	90.00 (77–102)	80.00 (66–93)	72.00 (62–84)	82.00 (73–93)	71.00 (59–83)
Skew/Kurtosis	0.06/−0.35 (N)	−0.79/−0.14 (N)	−0.19/−0.27 (N)	−0.11/−0.50 (N)	−0.31/−0.10 (N)	0.07/−0.62 (N)
Women (n = 127)
Mean (SD)	74.72 (21.61)	82.55 (18.80)	75.21 (18.25)	67.14 (20.36)	76.73 (22.16)	65.57 (19.99)
Median (IQR)	75.00 (60–92)	84.00 (70–102)	78.00 (60–85)	69.00 (47–81)	80.00 (63–91)	65.00 (49–80)
Skew/Kurtosis	0.20/−0.30 (Y)	−0.58/−0.57 (N)	−0.18/−0.45 (N)	0.29/−0.34 (N)	−0.09/−0.46 (N)	0.47/−0.55 (Y)
No substance abuse (n = 201)
Mean (SD)	78.75 (21.75)	87.33 (17.34)	76.62 (18.24)	70.04 (19.06)	79.15 (22.05)	69.53 (19.56)
Median (IQR)	78.00 (65–92)	90.00 (77–102)	78.00 (65–89)	72.00 (57–83)	80.00 (68–93)	69.00 (55–83)
Skew/Kurtosis	0.09/−0.42 (Y)	−0.81/−0.11 (N)	−0.23/−0.47 (N)	−0.01/−0.31 (N)	−0.13/−0.40 (N)	0.23/−0.64 (N)
Substance abuse (n = 134)
Mean (SD)	78.12 (19.10)	85.25 (17.33)	78.77 (17.47)	69.11 (20.14)	78.82 (19.33)	68.15 (18.41)
Median (IQR)	78.00 (66–92)	90.00 (77–102)	78.00 (66–91)	70.00 (55–83)	80.00 (73–91)	69.00 (54–81)
Skew/Kurtosis	0.05/−0.31 (Y)	−0.66/−0.36 (N)	−0.12/−0.14 (N)	0.10/−0.71 (N)	−0.47/−0.10 (N)	0.14/−0.80 (N)
<High school (n = 196)
Mean (SD)	74.21 (20.21)	83.64 (17.70)	75.57 (16.47)	64.99 (17.56)	75.12 (21.00)	64.11 (17.70)
Median (IQR)	73.00 (60–89)	84.00 (75–102)	78.00 (65–87)	68.00 (49–77)	77.00 (63–88)	64.00 (49–77)
Skew/Kurtosis	0.15/−0.43 (Y)	−0.56/−0.47 (N)	−0.25/−0.32 (N)	−0.06/−0.95 (N)	−0.26/−0.76 (N)	0.29/−0.74 (N)
High school (n = 68)
Mean (SD)	78.79 (19.39)	87.26 (17.82)	75.37 (19.07)	69.91 (21.36)	80.60 (19.67)	69.32 (17.64)
Median (IQR)	78.00 (67–92)	90.00 (77–102)	76.50 (59–89)	71.00 (51–84)	82.00 (73–91)	71.50 (55–82)
Skew/Kurtosis	−0.10/−0.12 (Y)	−0.93/0.09 (N)	−0.23/−0.72	0.26/−0.25 (N)	−0.34/0.27 (N)	−0.04/−0.63 (Y)
>High school (n = 71)
Mean (SD)	90.04 (18.99)	93.65 (13.53)	84.77 (19.06)	82.34 (17.02)	88.27 (19.19)	82.08 (18.08)
Median (IQR)	92.00 (75–102)	96.00 (84–102)	85.00 (75–97)	81.00 (72–94)	88.00 (74–100)	81.00 (68–96)
Skew/Kurtosis	0.15/−0.40 (Y)	−10.01/0.08 (N)	−0.38/−0.04 (Y)	−0.26/0.32 (Y)	0.10/0.17 (Y)	0.00/−0.82 (Y)

RBANS: The repeatable battery for assessment of neuropsychological status; SD: standard deviation; IQR: interquartile range. (Y) = yes and (N) = no for approximating a normal distribution based on the Kolmogorov–Smirnov test with Lilliefors Significance Correction.

Table 2. Clinical normative data for patients with schizophrenia spectrum disorder: RBANS index scores corresponding to classification ranges.

	Extremely low	Unusually low	Low average	Average	High average	Superior
All patients (N = 335)
Immediate memory	–	40–47	48–65	66–91	92–105	106+
Visuospatial/Constructional	40–47	48–59	60–76	77–101	102–107	–
Language	–	40–51	52–65	66–89	90–99	100+
Attention	–	–	40–54	55–82	83–94	95+
Delayed memory	–	40–42	43–69	70–91	92–105	106+
Total scale	–	–	40–53	54–82	83–95	96+
Men (n = 208)
Immediate memory	40	41–52	53–67	68–94	95–109	110+
Visuospatial/constructional	40–52	53–63	64–76	77–101	102–107	–
Language	–	40–52	53–65	66–92	93–98	99+
Attention	–	–	40–60	61–83	84–95	96+
Delayed memory	–	40–44	45–72	73–92	93–107	108+
Total scale	–	40–43	44–59	60–82	83–96	97+
Women (n = 127)
Immediate memory	–	40	41–57	58–92	93–99	100+
Visuospatial/constructional	–	40–53	54–69	70–102	103–107	–
Language	–	40–44	45–60	61–85	86–100	101+
Attention	–	–	40–45	46–81	82–93	94+
Delayed memory	–	–	40–62	63–91	92–104	105+
Total scale	–	–	40–48	49–79	80–93	94+
<High school (n = 196)
Immediate memory	–	40–43	44–58	59–88	89–99	100+
Visuospatial/constructional	40–44	45–56	57–70	71–101	102–107	–
Language	–	40–52	53–60	61–87	88–95	96+
Attention	–	–	40–47	48–77	78–88	89+
Delayed memory	–	–	40–58	59–88	89–101	102+
Total scale	–	–	40–48	49–77	78–90	91+
High school (n = 68)
Immediate memory	–	40–46	47–66	67–92	93–109	110+
Visuospatial/constructional	–	40–58	59–76	77–102	103–107	–
Language	–	40–42	43–58	59–89	90–101	102+
Attention	–	–	40–49	50–83	84–97	98+
Delayed memory	–	40–46	47–72	73–90	91–104	105+
Total scale	–	40–41	42–53	54–81	82–90	91+
>High school (n = 71)
Immediate memory	40–53	54–65	66–74	75–101	102–120	121+
Visuospatial/constructional	40–59	60–69	70–83	84–102	103–107	–
Language	–	40–57	58–72	73–97	98–109	110+
Attention	–	40–64	65–70	71–93	94–105	106+
Delayed memory	40–44	45–69	70–74	75–99	100–118	119+
Total scale	40–50	51–60	61–67	68–96	97–105	106+

RBANS: The repeatable battery for assessment of neuropsychological status.

Table 3. Base rates of low RBANS index scores in patients with schizophrenia spectrum disorder.

		Gender		Level of education			Intellectual abilities
Number of index scores below cutoff	All patients (N = 335)	Men (n = 208)	Women (n = 127)	<High school (n = 196)	High school (n = 68)	>High school (n = 71)	NART FSIQ <100 (n = 93)	NART FSIQ ≥100 (n = 115)	WAIS-IV FSIQ <80 (n = 34)	WAIS-IV FSIQ ≥80 (n = 50)
< 1 SD
1 or more	93.7	92.8	95.3	96.4	95.6	84.5	95.7	93.0	–	93.7
2 or more	79.1	76.4	83.5	86.7	79.4	57.7	91.4	73.9	–	79.1
3 or more	65.7	61.5	72.4	73.0	67.6	43.7	80.6	54.8	100.0	65.7
4 or more	45.4	40.4	53.5	53.6	42.6	25.4	60.2	35.7	82.4	45.4
5	21.5	16.8	29.1	29.6	14.7	5.6	32.3	11.3	44.1	44.1
< 10th percentile
1 or more	88.7	88.5	89.0	92.9	91.2	74.6	94.6	86.1	–	88.7
2 or more	73.7	71.6	77.2	82.1	73.5	50.7	87.1	67.8	–	73.7
3 or more	56.1	52.4	62.2	64.3	54.4	35.2	68.8	45.2	100.0	56.1
4 or more	37.0	32.7	44.1	45.9	33.8	15.5	48.4	27.8	76.5	37.0
5	14.6	11.5	19.7	19.9	10.3	4.2	21.5	7.0	32.4	14.6
≤ 5th percentile
1 or more	81.8	80.3	84.3	87.2	82.4	66.2	87.1	79.1	–	81.8
2 or more	63.3	60.6	67.7	71.4	64.7	39.4	75.3	48.7	100.0	63.3
3 or more	42.4	38.0	49.6	52.6	32.4	23.9	57.0	28.7	85.3	42.4
4 or more	24.2	21.2	29.1	31.1	23.5	5.6	30.1	16.5	50.0	24.2
5	9.0	7.2	11.8	11.7	8.8	1.4	15.1	3.5	23.5	9.0
< 2 SDs
1 or more	66.0	64.4	68.5	74.0	64.7	45.1	80.6	55.7	97.1	66.0
2 or more	40.0	35.6	47.2	50.5	30.9	19.7	58.1	27.8	85.3	40.0
3 or more	23.9	17.8	33.9	31.1	23.5	4.2	31.2	16.5	52.9	23.9
4 or more	13.4	8.2	22.0	16.8	14.7	2.8	18.3	9.6	29.4	13.4
5	3.0	1.0	6.3	3.1	5.9	0.0	5.4	0.0	14.7	3.0

Values represent cumulative percentages of people.

NART: National Adult Reading Test (Norwegian research version); WAIS-IV: Wechsler Adult Intelligence Scale-Fourth Edition; FSIQ: Full Scale Intelligence Quotient.