Cerebral Hemodynamics With rTMS in Alcohol Dependence
Condition: Alcohol Dependence
MeSH terms: Alcoholism
Study type: Interventional

Summary: 
      The present study measures the cerebral hemodynamic indices of alcohol dependent patients and
      observe the relative changes in these parameters with rTMS application.
    

Detailed description: 
      Alcohol abuse is a worldwide problem causing serious physical, psychological, social and
      economic consequences. Chronic alcohol intake has been found to increased blood viscosity,
      erythrocyte deformability or dehydration resulting in alterations of cerebral blood flow
      measures. Transcranial Doppler (TCD) sonography is a non-invasive radiological tool used for
      assessing the hemodynamics of the basal cerebral arteries, which can thus indirectly reflect
      the relative changes in regional cerebral blood flow velocity (CBFV) and vascular wall
      resistance. It has been used to evaluate the relative cerebral blood flow velocity changes in
      various psychiatric disorders like depression, schizophrenia, panic disorder, and substance
      use disorders including alcohol and marijuana. TCD also gives a real time assessment of the
      abrupt or short and long lasting effects of any external mechanical manipulation or
      functional stimulation of the intracranial circulation.

      The Mean flow velocity (MV) is the average of the edge frequency over a cardiac cycle; the
      edge frequency being the envelope of instantaneous peak velocities throughout the course of a
      cardiac cycle. Pulsatility index (PI) represents an estimate of downstream vascular
      resistance; low resistance vascular beds have higher diastolic flow velocities than high
      resistance vascular beds, hence they have low PI, and vice versa. Similarly, Resistance index
      (RI) is another presumptive measure of downstream vascular resistance.

      TCD sonography studies in alcoholism have revealed reduced mean blood flow velocities in
      basal cerebral arteries in chronic alcohol dependence, [1] as well as in acute stage of
      intoxication, but an increase after resolution of withdrawal state. [12] However, ethanol in
      low concentration has been found to increase the systolic, diastolic and mean blood flow
      velocity in middle cerebral arteries (MCA), anterior cerebral arteries (ACA) and decrease the
      resistance indices by reducing the cerebrovascular resistance in healthy individuals. Studies
      have reported that alcohol related hepatic dysfunction results in increased blood viscosity
      and reduced velocity in the cerebral arteries, which can be a risk factor for ischemic brain
      diseases. So, normalization of hemodynamic parameters is important in the prevention of
      possible ischemic brain diseases due to alcohol dependence.

      Studies evaluating cerebral hemodynamic response to rTMS application have been limited to
      healthy individuals, with high frequency rTMS application found to increase the cerebral
      blood flow velocities in both anterior and posterior basal cerebral arteries, and low
      frequency rTMS to temporarily decrease the blood flow velocity in ipsilateral MCA followed by
      an increase in the contralateral MCA. With this background, the present study was conducted
      to measure the cerebral hemodynamic indices of alcohol dependent patients and observe the
      relative changes in these parameters with rTMS application.
    

Intervention name(s): Repetitive Transcranial Magnetic Stimulation (rTMS)
Intervention type(s): Device
Intervention description(s): The motor threshold for the left abductor pollicis brevis was determined using a figure-of-eight-shaped coil at 1 Hz frequency. Ten (over 2 weeks) rTMS sessions were administered over the right dorsolateral prefrontal cortex with an air-cooled figure-of-eight coil, angled tangentially to the head. At right DLPFC, active high-frequency (10 Hz) stimulation was administered for 4.9 seconds per train, with inter-train interval of 30 seconds, and a total of 20 trains per session. Each patient received 1000 pulses per day. The sham group was administered rTMS with the same parameters, but using a figure-of-eight sham coil.
Allocation: Randomized
Intervention model: Parallel Assignment
Masking: Single (Participant)
Primary purpose: Treatment
Keywords: Transcranial Doppler (TCD) sonography; rTMS; Cerebral hemodynamics