Non-invasive, bedside intra-cranial pressure and brain shift/herniation monitoring unit utilizing early on-set auditory evoked responses

Abstract

Systems and methods are taught for non-invasively monitoring brainstem function and intra-cranial pressure in a patient. Repeated auditory stimulation is applied to the patient in at least one ear to generate an auditory brainstem response. The response waveform is detected with an electrode at a location on the patient's head. The detected waveform data is compared with known waveform data and an alarm is initiated when a change in the auditory brainstem response is detected based on the comparison that is indicative of a corresponding change in intra-cranial pressure in the patient.

What is claimed is: 
     
         1 . A method of non-invasively monitoring brainstem function, comprising the steps of
 repeatedly auditorially stimulating a patient at a first location over a period of time to evoke brainstem-generated electrical waveform data,   detecting the brainstem-generated electrical waveform data electronically at a location separate from said first location,   comparing the detected brainstem-generated electrical waveform data with at least one selected from a group consisting of established patient baseline waveform data, established normative range and abnormal range waveform data, and earlier waveform data obtained from the patient, and   detecting a change in the brainstem function of the patient over the period of time based on the comparison.   
     
     
         2 . The method according to  claim 1 , in which repeatedly auditorially stimulating a patient at a first location includes repeatedly auditorially stimulating the patient in a first ear using one acoustic ear insert. 
     
     
         3 . The method according to  claim 2 , further comprising repeatedly auditorially stimulating the patient in a second ear using a second acoustic ear insert. 
     
     
         4 . The method according to  claim 1 , in which detecting the brainstem-generated electrical waveform data electronically includes detecting the brainstem generated electrical waveform data electronically using at least one selected from a group consisting of a cranial electrode and a neck electrode. 
     
     
         5 . The method according to  claim 1 , in which repeatedly auditorially stimulating the patient includes applying a pure tone burst stimulus. 
     
     
         6 . The method according to  claim 5 , in which detecting the brainstem-generated waveform data includes detecting waveform data comprising at least one selected from a group consisting of Wave V and Wave V n . 
     
     
         7 . The method according to  claim 5 , in which applying the pure tone stimulus includes applying the pure tone burst stimulus at a rate of from about 40 per second to about 70 per second. 
     
     
         8 . The method according to  claim 1 , in which detecting the brainstem-generated waveform data includes detecting an auditory brainstem response waveform, and in which repeatedly auditorially stimulating the patient includes auditorially stimulating using a click stimulus. 
     
     
         9 . The method according to  claim 8 , in which auditorially stimulating using the click stimulus is includes applying the click stimulus at a rate of from about 11 per second to about 22 per second. 
     
     
         10 . The method according to  claim 8 , in which detecting the brainstem-generated waveform data includes detecting brainstem-generated electrical waveform data comprising at least one selected from a group consisting of Wave V and Wave V. 
     
     
         11 . The method according to  claim 1 , in which detecting the brainstem-generated waveform data includes detecting brainstem-generated electrical waveform data comprising a modified auditory brainstem response waveform, and in which repeatedly auditorially stimulating the patient includes auditorially stimulating using a rapid click stimulus. 
     
     
         12 . The method according to  claim 11 , in which auditorially stimulating using the rapid click stimulus includes applying the click stimulus at a rate of from about 40 per second to about 70 per second. 
     
     
         13 . The method according to  claim 11 , in which detecting the brainstem-generated waveform data includes detecting brainstem-generated electrical waveform data comprising at least one selected from a group consisting of Wave V and Wave V n . 
     
     
         14 . The method according to  claim 11 , in which repeatedly auditorially stimulating the patient includes applying in at least one ear, at a plurality of moderate and diminishing loudness intensities, at least one selected from a group consisting of a pure tone burst stimulus and a click stimulus. 
     
     
         15 . A method of non-invasively monitoring cranial pressure in a patient, comprising the steps of
 repeatedly auditorially stimulating a patient in at least one ear to generate an auditory brainstem response waveform;   detecting the auditory brainstem response waveform with an electrode at a location on a head of the patient;   comparing the detected waveform with known waveform data; and   initiating an alarm when a change in the auditory brainstem response waveform is detected based on the comparison, wherein the detected change in the auditory brainstem response waveform is indicative of a corresponding change in cranial pressure.   
     
     
         16 . The method according to  claim 15 , in which repeatedly auditorially stimulating a patient includes repeatedly auditorially simulating the patient in a first ear using at least one acoustic ear insert. 
     
     
         17 . The method according to  claim 16 , further comprising repeatedly auditorially stimulating the patient in a second ear using a second acoustic ear insert. 
     
     
         18 . The method according to  claim 15 , in which detecting the auditory brainstem-response waveform data includes detecting an auditory brainstem-response waveform comprising at least one selected from a group consisting of Wave V and Wave V n . 
     
     
         19 . The method according to  claim 15 , in which repeatedly auditorially stimulating a patient includes applying an auditory stimulus at a plurality of moderate and diminishing loudness intensities. 
     
     
         20 . The method according to  claim 15 , in which repeatedly auditorially stimulating a patient in at least one ear includes applying a pure tone stimulus. 
     
     
         21 . The method according to  claim 15 , in which repeatedly auditorially stimulating a patient in at least one ear includes applying a rapid click stimulus. 
     
     
         22 . The method according to  claim 15 , further comprising:
 detecting a first auditory brainstem response waveform with the electrode at the location on the head of the patient; and   storing data indicative of the first auditory brainstem response waveform to a memory,   wherein detecting the auditory brainstem response waveform includes detecting a second auditory brainstem response waveform, the second auditory brainstem response waveform being detected subsequent to the first auditory brainstem response waveform, and   wherein comparing the detected waveform with known waveform data includes comparing the second auditory brainstem response waveform with the stored data indicative of the first auditory brainstem response waveform.   
     
     
         23 . The method according to  claim 15 , further comprising defining a normative range of waveform data,
 wherein comparing the detected waveform with the known waveform data includes comparing the detected waveform data with the defined normative range, and   wherein initiating the alarm when the change in the auditory brainstem response waveform is detected includes initiating the alarm when waveform data is detected that is outside of the defined normative range.