TABLE 2.
Summary of motor cortical excitability studies using rTMS in traumatic brain injury
| Study | TBI type | Patient # (duration after trauma) |
Coil | TMS | Intensity | Tested measures | Results |
|---|---|---|---|---|---|---|---|
| Chistyakov 1998 | minor TBI | 39 P, 21 C (2 weeks, 3 months) |
R | single pulse rTMS (1 Hz, 50 pulses) |
130-135% MT (70-90% MO) 110-115% MT |
MT CMCT MEP amplitude MEP variability |
Higher MT in TBI group Abnormal variability of MEP amplitude with rTMS: (a) progressive decrease of amp, complete abolition (b) irregular amplitude and chaotic form 3 months later- MEP variability and MT return to normal values in relation to clinical recovery |
| Chistyakov 1999 | minor TBI moderate TBI (diffuse/focal) |
64 P, 16 C (N/A) |
R | single pulse rTMS (1 Hz, 50 pulses) |
130-135% MT (70-90% MO) 110-115% MT |
MT MEP amplitude MEP variability CMCT SEP |
Higher MT and abnormal MEP variability in TBI group Higher pathological MEP findings in the moderate TBI group MEP abnormalities were more prominent in patients with clinical complaints and with focal contusions SEP and CMCT abnormalities were more prominent in DAI group |
| Moosavi 1999 | severe TBI anoxic BI |
19 P (13 TBI), 13 C (>6 months) |
R DC |
single pulse | 100% MT | MT MEP amplitude MEP variability CMCT |
Higher MT in the group unresponsive to verbal commands or multimodal sensory stimulation |
| Chistyakov 2001 | minor TBI moderate TBI |
38 P, 20 C (2 weeks) |
R | single pulse | 130% MT | MT MEP amplitude CMCT SP |
Higher MT and reduced MEP amplitude in mild to moderate TBI SP duration longer at 130% MT but not at lower intensities The degree of MEP and SP changes depended on severity of TBI |
| Centonze 2005 | minor TBI, minor TBI+PTSD |
25 P (14PTSD), 12 C (1-6 months) |
8 | single pulse paired pulse |
Co: 90% MT T: 500 μV |
MT MEP ISI 1-6 ms |
No significant differences between TBI and controls Less inhibition at ISI 2, 3, 4 ms in TBI+PTSD |
| Jang 2005 | DAI | 8 P, 13 C (4 months) |
R | single pulse | 120% MT | MT MEP fMRI |
No significant differences for MT or MEP amplitude Greater MEP duration and turns in the patient group No significant differences in M1 activated by the hand movements |
| Crossley 2005 | severe TBI | Case (4 weeks, 1 year) |
R | single pulse | N/A | MEP PET EEG SEP |
Increase in MEP amplitude compared to 4 weeks Increase in metabolic rate and regression in reduction (27% to 21%) Slow background EEG activity (theta frequency) was replaced with normal background activity (alpha frequency) |
| Barba 2005 | severe TBI | Case (3 months) |
8 | single pulse | 110% MT | MT MEP FMRI TCD |
Higher MT Reduced cortical representation via motor mapping, Lower voxels of brain activations via quantitative fMRI Altered vasomotor reactivity via TCD |
| Fujiki 2006 | DAI | 16 P, 16 C | 8 | single pulse paired pulse |
Co: 95% MT T: 1000 μV |
MT ISI 3,4,5,10,12,14 |
No significant differences between DAI and controls |
| Takeuchi 2006 | DAI | 20 P, 20 C | 8 | single pulse | 120% MT 150% MT |
MT MEP TCI (iMEP) |
TCI was significantly lower in patients and correlated with GCS |
| Yasokawa 2007 | DAI | 52 P, 17 C | 8 | single pulse | 50-100% MO | MT MEP DTI |
FA was significantly reduced in MEP (-) group FA reversely correlated with the increase in MT in MEP(+) group |
| Beaumont 2007 | mild TBI (concussion) |
30 P, 15 C (>9 months) |
8 | single pulse paired pulse |
Co: 80% MT T: 120% MT SP: 120% MT |
MT ISI 1,2,3,6,9,12 I/O SP |
SP was prolonged in the group with multiple concussions SP correlated with concussion severity |
| Beaumont 2009 | mild TBI (concussion) |
19 P, 21 C (27-41 years) |
8 | single pulse paired pulse |
Co: 80% MT T: 120% MT SP: 110, 120, 130% MT |
MT ISI 2,3,9,12,15 I/O SP |
SP was significantly prolonged and correlated with bradykinesia |
| Bernabeu 2009 | severe TBI+ DAI | 17 P, 11 C (>6 months) |
8 | single pulse | 110% MT | MT MEP area MEP variability I/O SP |
Higher MT, smaller MEP areas, narrower I/O curves Changes were more pronounced with DAI severity and motor dysfunction SP not significantly different |
Abbreviations: TBI: traumatic brain injury, DAI: diffuse axonal injury, PTSD: post traumatic stress disorder, P; patients, C: controls, N/A: not applicable, R; round coil, DC: double-cone coil, 8: figure-of-eight coil, MO: maximum machine output, MT: motor threshold, Co: conditioning stimulus, T: test stimulus, SP: silent period, CMCT: central motor conduction time, MEP: motor evoked potential, SEP: somatosensory evoked potential, ISI: interstimulus interval, fMRI: functional magnetic resonance imaging, PET: positron emission tomography, TCD: transcranial Doppler, TCI: transcallosal inhibition, iMEP: ipsilateral MEP, DTI: diffusion tensor imaging, I/O: input output curves, M1: primary motor cortex, GCS: glaskow coma scale, FA: fractional anisotropy.