Scalp Acupuncture for Lacunar Infarction: Points and Protocols

Lacunar infarction, also known as lacunar stroke, lacunar infarct, or cerebral lacunar infarction, refers to small infarcts in the deep regions of the brain caused by occlusion of the deep perforating arteries and their branches.

This condition is primarily caused by long-term hypertension, accounting for approximately two-thirds of cases. Persistent hypertension acts on the walls of small arteries and arterioles, leading to fibrinoid necrosis, hyaline degeneration, microatheroma formation, and atheromatous plaques, ultimately resulting in stenosis and occlusion of the deep penetrating arteries. The remaining causes, accounting for about one-third of cases, include various etiologies such as cerebral atherosclerosis, carotid artery stenosis and occlusion, vasculitis, leukemia, polycythemia vera, metastatic carcinoma, and abscesses. These induce ischemia, thrombosis, or cardioembolic infarction in the deep arteries, producing small areas of encephalomalacia (lacunar infarcts).

The predilection sites for this condition are the basal ganglia, internal capsule, thalamus, basis pontis, and the periventricular region of the lateral ventricle (also known as the corona radiata or junctional zone). Lesions may be single, but multiple occurrences are also common. The primary pathogenesis involves long-standing hypertension, which leads to elongation of the basilar artery, displacement of penetrating arteries, vascular tortuosity, and further reduction of blood flow, resulting in ischemia. The internal capsule and its surrounding structures constitute a watershed zone for cerebral arterial blood supply and are often in a state of low perfusion. Coupled with stenosis of deep penetrating arteries due to hypertensive small-vessel disease, thrombosis is prone to occur, leading to occlusion and subsequent formation of softening foci (lacunar infarcts).

I. Diagnostic Points

This condition often has a long history of hypertension. Some patients may be asymptomatic after onset, and approximately 20% of patients have a history of transient ischemic attack (TIA). The following five types are commonly encountered in clinical practice:

(1) Simple Motor Disorder

The main manifestation is mild hemiparesis, with unilateral weakness of the face, arm, and leg, and occasional reports of paresthesia, but without objective sensory deficits. The lesion is located on the contralateral corticospinal tract pathway, involving the corona radiata, internal capsule, and pons.

(2) Pure Sensory Disturbance

Unilateral abnormal or decreased sensation in the face, arm, and leg; typical hemisensory disturbance strictly distributed along the midline; with or without objective sensory deficits; the lesion is located in the contralateral thalamic sensory nuclei (i.e., ventral nuclei).

(3) Sensorimotor Stroke (Zhongfeng)

Unilateral weakness of the face, arm, and leg, accompanied by ipsilateral sensory abnormalities or hypoesthesia (excluding cases involving only the face or leg). The lesion is located in the contralateral posterior limb of the internal capsule and the ventroposterolateral nucleus of the thalamus, typically resulting from occlusion of the thalamoperforating artery or the posterior choroidal artery of the posterior cerebral artery.

(4) Ataxic Hemiparesis

Mild hemiparesis predominantly in the lower limb, accompanied by marked ipsilateral limb ataxia, with occasional reports of paresthesia or mild sensory loss. The lesion is located in the contralateral base of the pons, resulting from lacunar infarction of the paramedian branches of the basilar artery.

(5) Dysarthria-Clumsy Hand Syndrome

The patient presents with central facial palsy and lingual palsy, accompanied by dysarthria, choking upon swallowing, impaired fine motor coordination of the hand, instability on the finger-to-nose test, and occasional pyramidal signs, but without significant limb paralysis. The lesion is located in the contralateral pontine base or the genu of the internal capsule.

In clinical practice, pseudobulbar palsy, pseudoparkinsonism syndrome, dementia, etc. may also be observed, but they are less common.

II. Treatment

(1) Acupoints

1. Motor Area (Healthy Side): This corresponds to the projection of the precentral gyrus (primary motor cortex) onto the scalp. The upper point is located 0.5 cm posterior to the anterior-posterior midline (the line connecting the glabella to the highest point of the external occipital protuberance). The lower point is at the intersection of the eyebrow-occipital line and the anterior margin of the temporal hairline. The connecting line between these two points defines the motor area. – The upper 1/5 of the motor area is indicated for contralateral lower limb paralysis. – The middle 2/5 of the motor area is indicated for contralateral upper limb paralysis. – The lower 2/5 of the motor area is indicated for contralateral central facial paralysis, motor aphasia, drooling, and speech disorders.

2. Sensory Area (contralateral side): Corresponds to the projection area of the postcentral gyrus (primary sensory cortex) on the scalp. Located parallel to and 1.5 cm posterior to the motor area, the sensory area is divided into three sections: the upper 1/5 treats contralateral lower back and leg pain, numbness, sensory abnormalities, as well as pain in the posterior head, neck, and tinnitus; the middle 2/5 treats contralateral upper limb pain, numbness, and sensory abnormalities; the lower 2/5 treats contralateral facial numbness, migraine, trigeminal neuralgia, toothache, and temporomandibular joint arthritis.

3. Foot Motor-Sensory Area (contralateral): Located 1 cm posterior to the upper point of the sensory area and 1 cm lateral to the anterior–posterior midline, a 3 cm parallel line is drawn forward from this point. Indications: paralysis of the lower limbs, contralateral lumbocrural pain and numbness, cortical nocturia, polyuria, prolapse of the rectum, and uterine prolapse.

4. Speech Area 3 (healthy side): Located 1.5 cm above the ear apex, this area is a horizontal line extending 4 cm posteriorly from the midpoint of the Vertigo-Auditory Area. It is indicated for sensory aphasia.

(2) Methods

The main approach is symptomatic acupoint selection. For example, when there is motor dysfunction of the upper and lower limbs, poor articulation (dysarthria), or tongue paralysis, acupuncture may be applied to the upper 1/5, middle 2/5, and lower 2/5 of the Motor Area. In cases of bilateral lower limb paralysis accompanied by ataxia, needle the Motor Area bilaterally, the upper 1/5 of the Sensory Area bilaterally, plus the Foot Motor-Sensory Area bilaterally and the Balance Area bilaterally.

The patient is placed in a sitting position. After selecting the required area for needling, a 30-gauge, 1.5-cun filiform needle is used. Routine local disinfection is performed, and the needle is inserted into the selected points using the relay flat insertion technique (jie li ping ci fa). The needle is retained for 1 hour, with one intermediate twirling. Treatment is given once daily, with 10 sessions constituting one course. A 5-day rest is taken before the next course.

III. Commentary

The prognosis for patients with this condition is generally favorable, and they will recover quickly. However, for a subset of patients whose above symptoms recur repeatedly due to multiple episodes, the aforementioned treatment methods should be applied. As long as acupoint selection is appropriate and precise, satisfactory results can be achieved within a relatively short period of time.

For patients with a longer duration of the condition, although a slightly longer treatment period is required, satisfactory results can still be achieved.

Pathophysiology and Rationale for Scalp Acupuncture in Lacunar Infarction

Lacunar infarction results from occlusion of deep perforating arteries, typically driven by long-term hypertension, leading to small ischemic lesions in subcortical structures such as the basal ganglia, thalamus, and internal capsule. Scalp acupuncture is increasingly recognized as a targeted neuromodulatory intervention for these deep-seated infarcts. The rationale lies in the somatotopic organization of the cerebral cortex: stimulating defined zones on the scalp—corresponding to motor, sensory, and speech areas—can enhance collateral blood flow, promote neuroplasticity, and reduce secondary neuronal damage. Specifically, scalp acupuncture for lacunar stroke points involves needling zones such as the anterior oblique line of the vertex-temporal (MS6) and the posterior oblique line of the vertex-temporal (MS7), which overlie the precentral and postcentral gyri. These points are believed to activate descending corticospinal pathways and facilitate functional recovery. By modulating cerebral hemodynamics through autonomic and local reflex mechanisms, scalp acupuncture addresses both the acute ischemic insult and the chronic sequelae of lacunar infarction, offering a complementary approach to conventional pharmacotherapy and rehabilitation.

Standardized Acupuncture Protocols for Lacunar Infarction

Clinical acupuncture protocols for lacunar infarction typically combine scalp acupuncture with body acupuncture, but the scalp component is prioritized for its direct cortical influence. A standard session involves selecting scalp acupuncture points for lacunar infarct based on the lesion location: the motor area (MS6) for hemiparesis, the sensory area (MS7) for paresthesia, and the speech area (MS8) for aphasia. Needles (0.25–0.30 mm diameter, 25–40 mm length) are inserted subcutaneously at a 15–30° angle, then manipulated manually with a twisting technique (200–300 twists per minute) for 1–2 minutes every 10 minutes during a 30–40 minute session. Alternatively, electroacupuncture at 2–4 Hz low-frequency stimulation is applied to enhance afferent input. Treatment frequency is three to five times per week for four to eight weeks, with outcome measures focused on the National Institutes of Health Stroke Scale (NIHSS) and the Barthel Index. Adjunctive body points such as GB34 (Yanglingquan) and ST36 (Zusanli) may be added, but the core protocol relies on the precise localization of scalp zones to target the ischemic penumbra and stimulate cortical reorganization.

Clinical Efficacy and Neurophysiological Mechanisms

Controlled trials indicate that integrating scalp acupuncture into the management of lacunar infarction significantly improves motor function, balance, and activities of daily living compared to rehabilitation alone. Neuroimaging studies reveal that scalp acupuncture for lacunar stroke points increases regional cerebral blood flow in the perilesional cortex and ipsilesional thalamus, as measured by arterial spin labeling. This effect is attributed to the release of vasoactive peptides (e.g., calcitonin gene-related peptide) and the activation of the cholinergic anti-inflammatory pathway. Furthermore, acupuncture protocols for lacunar infarction upregulate brain-derived neurotrophic factor (BDNF), promoting synaptogenesis and axonal sprouting in the corticospinal tract. Importantly, the timing of intervention matters: early application within the first two weeks post-infarct yields greater gains in neural plasticity. Current evidence supports the safety and tolerability of these protocols, with minor adverse events limited to local hematoma or dizziness. Future research should refine the optimal scalp acupuncture points for lacunar infarct based on diffusion tensor imaging tractography, thereby personalizing treatment to individual lesion anatomy and maximizing restorative outcomes.