Table 4.
Types of putative biomarkers for disease progression investigated in the 183 included articles
| All studies (n=183) | Longitudinal studies (n=20) | Cross-sectional studies (n=163) | ||||
|---|---|---|---|---|---|---|
|
Biomarker modality |
Number of studies examining biomarker |
% |
Number of studies examining biomarker |
% |
Number of studies examining biomarker |
% |
| Serum/plasma/blood |
51 |
27.9 |
0 |
0.0 |
51 |
31.3 |
| Brain SPECT |
41 |
22.4 |
9 |
45.0 |
32 |
19.6 |
| Brain PET |
31 |
16.9 |
8 |
40.0 |
23 |
14.1 |
| CSF |
29 |
15.8 |
0 |
0.0 |
29 |
17.8 |
| Brain MRI |
15 |
8.2 |
1 |
5.0 |
14 |
8.6 |
| Cardiac 123I-MIBG scintigraphy |
9 |
4.9 |
0 |
0.0 |
9 |
5.5 |
| Electrophysiology |
9 |
4.9 |
1 |
5.0 |
8 |
4.9 |
| Ultrasound |
7 |
3.8 |
0 |
0.0 |
7 |
4.3 |
| Urine |
5 |
2.7 |
0 |
0.0 |
5 |
3.1 |
| Brain MRS |
2 |
1.1 |
0 |
0.0 |
2 |
1.2 |
| Other | 3 | 1.6 | 1 | 5.0 | 2 | 1.2 |
19 cross-sectional studies examined for a relationship between two different biomarker modalities and a clinical measure of disease progression. (SPECT, single-photon emission computed tomography; PET, positron emission tomography; CSF, cerebrospinal fluid; MRI, magnetic resonance imaging; 123I-MIBG, 123I-metaiodobenzylguanidine; MRS, magnetic resonance spectroscopy).