Focal Increase in Cerebral Blood Flow After Treatment with Near-Infrared Light to the Forehead in a Patient in a Persistent Vegetative State

LED device

The transcranial LED treatments were performed beginning at 228 days post-severe head trauma, caused by a fall when fighting. This is an off-label use for the L-light (Fig. 1), which has a 78 mm wide and 72 mm long (23 diodes; peak wavelength,850 nm [830–870 nm, the full width half-maximum range]; 13 mW per diode; total power 299 mW; the spot size of each LED 0.95 cm²; SUN-MECHATRONICS, Tokyo, Japan) (Table 1). The half-value angle of LED is 6 degrees according to the manufacturer's specification. The device was applied at a distance of 5 mm away from the skin. The estimated beam area per diode on the skin was 1.14 cm²; the power density 11.4 mW/cm²; the energy density 20.5 J/cm² at the skin. The patient received transcranial LED treatments with placement of the L-light on the left and right forehead areas superior to the eyebrows for 30 min, 2 times daily, for 73 days. The dosage/treatment duration of 30 min twice a day was based on the results obtained in animal studies. ²

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Fig. 1.

A photograph of a model being treated, L-light (SUN-MECHATRONICS, Tokyo, Japan).

CBF measurement

Single-photon emission computed tomography with N-isopropyl-[123I]p-iodoamphetamine (IMP-SPECT) was performed twice. Prior to LED therapy, the IMP-SPECT scan was performed at 227 days post-head trauma. Post-LED therapy, the IMP-SPECT scan was performed at 300 days post-head trauma, and following 73 days of LED therapy, and 146 LED therapy treatments. It was performed within 30 min of the last LED treatment. At 10 min after the beginning of the IMP infusion, 3 mL of arterial blood was obtained from the radial artery. The whole-blood radioactivity of 1 mL of each blood sample obtained was measured by using a well counter that was cross-calibrated to the SPECT scanner. All reconstructed SPECT images were corrected for the radioactive decay of 123I back to the IMP injection start time, normalized by the data collection time, and cross-calibrated to the well counter system. The whole-blood radioactivity count of the single blood sample was referred to the standard input function. The absolute value of regional CBF (rCBF) was thus obtained.

Case presentation

A 40-year-old man underwent craniotomy over the left frontal areas and evacuation for traumatic acute subdural hematoma, secondary to a fall from fighting. Initial neurological examination showed a score of 5 on the Glasgow Coma Scale. He survived but was in a persistent vegetative state for 8 months after the trauma. He showed no spontaneous movement of limbs. A CT scan of the head 8 months after accident showed a focal low-density area in the right frontal lobe (Fig. 2A). He showed no symptoms and signs of increased intracranial pressure at 8 months. After approval by the institutional review board of National Defense Medical College, the appropriate informed consent was obtained, and the transcranial LED treatments were initiated. This is an off-label use for the L-light (SUN-MECHATRONICS, Tokyo, Japan) (Fig. 1 and Table 1). He received transcranial LED treatments with continuous-wave L-light on the left and right forehead areas superior to the eyebrows for 30 min twice daily for 73 days. The interval between the two treatments on the same day was 6 h. Five days after beginning the LED treatments (after 10 treatments), the patient began to move his left arm and hand to reach the site of tracheostomy when suctioning was performed. He had never shown any spontaneous movement prior to the LED treatments. After LED treatment for 2 months, which ended 300 days post-head trauma, he always showed spontaneous movement, but did not obey commands. We observed no further improvement in his neurological condition after LED treatments.

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Fig. 2.

(A) A CT scan of the head before any light-emitting diode (LED) treatments (performed at 220 days post-head trauma), showing a focal low-density area in the subcortical white matter, anterolateral to the right frontal horn; with a ventriculo-peritoneal shunt in place in the right frontal horn. (B) Single-photon emission CT with N-isopropyl-[123I]p-iodoamphetamine (IMP-SPECT) before LED treatment, performed at 227 days post-head trauma. IMP-SPECT scan at 30 min after the 146th LED treatment. The post-LED SPECT scan was performed 300 days post-head trauma. This post-LED SPECT scan showed a focal increase of 20%, compared with the pre-treatment value of regional cerebral blood flow in the left anterior frontal cortex (C, arrow).

IMP-SPECT showed focal increase (20% higher) of CBF in the viable left anterior frontal lobe 30 min after the 146th LED treatment, which was performed on the 73 days of the LED treatment series, and 300 days post-trauma (Fig. 2B and C).