Peri et al. (2001)

USA

RCT

PEDro=6

N=10

Population: TBI; Mean Age=40 yr; Gender: Male=8, Female=2; Mean Time Post Injury=6 2hr; Mean GCS=5.

Intervention: Participants were randomized to receive right median nerve stimulation (RMNS, n=6), with 300 msec intermittent pulses at 40 Hz (20 sec on and 40 sec off), or sham stimulation (n=4) for 8 hr/ day up to 14 days. Outcomes were assessed at 3mo.

Outcome Measures: Glasgow Coma Scale (GCS), Glasgow Outcome Scale (GOS), Functional Independence/Assessment Measure (FIM/FAM), Coma Duration.

1.        Mean coma duration was shorter in the RMNS group than the sham group, but this difference was not significant (9.5 days versus 11.5 days, p=0.31).

2.        There was no significant difference between RMNS and sham groups in GOS (3 versus 3) or FIM/FAM scores (114.4 versus 64.5).

Cooper et al. (1999)

USA

RCT

PEDro=4

N=6

Population: TBI; Mean Age=28 yr; Time Post Injury<1 wk; Mean GCS=7.

Intervention: Patients were randomized to receive right median nerve stimulation (RMNS, n=3), with asymmetric biphasic pulses (20 mA, 300 µs,  40 Hz, 20 sec/min) or sham stimulation (control, n=3) for 8-12 hr/day for 2 wk. Outcomes were assessed at 1 wk, 2 wk, and 1 mo.

Outcome Measures: Glasgow Coma Scale (GCS), Glasgow Outcome Scale (GOS), Length of Stay (LOS).

1.        At 1 wk, the RMNS group improved by an average of 4.0 on the GCS compared with 0.7 in controls.

2.        By 2 wk, the RMNS group improved by an average of 6.4 on the GCS compared with 1.3 in controls.

3.        The RMNS group LOS in the ICU was an average of 7.7 days compared with 17.0 days for controls.

4.        Mean GOS for the RMNS group was 3 compared with 2 for controls.

5.        No statistical comparisons were reported.

Lei et al. (2015)

China

Cohort

N=437

Population: TBI; Treatment Group (TG, n=221): Mean Age=41.31 yr; Gender: Male=154, Female=67; Mean GCS=6.27. Control Group (CG, n=216): Mean Age=43.21 yr; Gender: Male=145, Female=71; Mean GCS=6.31.

Intervention: Participants in a Minimally Conscious State (MCS) or vegetative state (VERSUS) were assigned to receive right median electrical stimulation (RMNS, TG) or standard care (CG). RMNS was delivered for 8 hr/day over 2 wk (15-20 mA, 40 Hz, 20 sec/min). Outcomes were assessed before and after each treatment session, with follow-up at 6mo.

Outcome Measures: Glasgow Coma Scale (GCS), Functional Independence Measure (FIM).

1.        Over 2 wk, GCS increased in both groups. The increase was more rapid in the TG than the CG, but the difference was not significant (p=0.1472).

2.        At end of 2 wk, mean GCS was higher in the TG than the CG, but the difference was not significant (8.43 versus 7.47, p=0.0532).

3.        At 6 mo, significantly more of the TG regained consciousness than the CG (60% versus 46%, p=0.0073).

4.        At 6mo, significantly more of the CG remained in VERSUS than the TG (32% versus 18%, p=0.0012), but there was no significant difference in those remaining in MCS (22% versus 23%, p=0.8929).

5.        At 6 mo, mean FIM score was significantly in the TG than the CG (91.45 versus 76.23, p<0.0001).

Liu et al. (2003)

Taiwan

Pre-Post

N=6

Population: TBI=2, Hypoxia=2, Stroke=1, Aneurysm=1.

Intervention: Patients received right median nerve stimulation (RMNS):  asymmetric biphasic pulses (20 mA, 300 µs,35 Hz, 20 sec on and 50 sec off).  Stimulation was performed for 1 0 hr/ day (comatose) or 8 hr/ day (conscious) for 3 mo.

Outcome Measures: Cerebral Perfusion Pressure (CPP), Dopamine levels.

1.        Significant increases in CPP were seen bilaterally in all patients following RMNS (p<0.05).

2.        Four patients regained consciousness within 35 days of initial RMNS.

3.        Dopamine levels were elevated in the majority of patients following RMNS.

4.        Younger patients (<40 yr) had better improvement than older patients.