Table 3

Subgroup analysis of the percentage of bulbar disease onset in the included studies

Cognitive domainBulbar onsetHedges’ g95% CIKNQp (Q)I2 (%)
Visuoconstructive functions<32.3
>32.3		0.83
0.44		−0.04 to 1.70
−0.02 to 0.89		2
2		 85
 76		0.620.430
Psychomotor speed<32.3
>32.3		0.40
0.38		0.05 to 0.75
  0.11 to 0.65		7
5		244
187		0.010.930
Fluency<32.3
>32.3		0.65
0.69		0.49 to 0.82
  0.48 to 0.89		8
7		313
291		0.060.800
Language<32.3
>32.3		0.66
0.35		0.37 to 0.96
−0.07 to 0.77		7
4		290
176		1.450.2331.3
Social cognition<32.3
>32.3		0.36
NA		−0.02 to 0.74
  NA		2
0		 79
  0		NANANA
MMSE<32.3
>32.3		0.53
0.53		0.20 to 0.86
  0.32 to 0.74		7
5		230
563		0.000.990
Executive functions<32.3
>32.3		0.56
0.57		0.39 to 0.73
  0.19 to 0.95		10
9		447
429		0.000.970
Delayed verbal memory<32.3
>32.3		0.51
0.38		0.16 to 0.86
−0.03 to 0.78		6
6		222
268		0.230.630
Immediate verbal memory<32.3
>32.3		0.43
0.57		0.21 to 0.65
  0.31 to 0.82		6
5		222
224		0.650.420
Attention<32.3
>32.3		0.36
0.50		0.16 to 0.56
  0.38 to 0.63		4
9		160
531		1.400.2428.5
Verbal IQ<32.3
>32.3		0.21
0.33		−0.01 to 0.44
  0.05 to 0.62		3
6		161
290		0.420.520
Visual memory<32.3
>32.3		0.11
0.35		−0.12 to 0.34
  0.12 to 0.58		7
4		269
179		2.010.1650.3
Visuoperceptive functions<32.3
>32.3		0.36
0.07		−0.04 to 0.77
−0.39 to 0.25		3
2		101
 86		2.720.1063.2

  • Bulbar onset: percentage of patients with bulbar disease onset; Hedges’ g: effect size; 95% CI: 95% CI of effect size; K: number of studies; N: number of participants; Q: heterogeneity between studies within cognitive domain; p (Q): p value for heterogeneity; I2: percentage of heterogeneity caused by study differences (Q—degrees of freedom/Q×100%); NA: not applicable.

  • MMSE, mini mental state examination.